The starter turns but the engine does not start. How to increase compression in a diesel engine, diesel does not start, diesel engine does not start, diesel starts poorly, increase in diesel engine power, why diesel does not start, diesel smokes

Because even the most modern cars are, after all, just technical devices, you always need to be prepared for the fact that at any moment one or even several units that ensure their operation may fail, as a result of which the machine will cease to function normally.

Any breakdown is always unpleasant for the driver. But experienced motorists will say that it is especially unpleasant when on the road engine suddenly stalls and cannot be started. Than it can be caused? Let's figure it out together and try to find suitable solutions.

The most common causes of diesel engine failure

One of the most common reasons why a diesel engine stops working is the failure of the injection pump. Another alternative could be the lack of fuel in the tank, but this is already a situation, rather, from a joke. The normal operation of the high pressure fuel pump (TNVD) is impossible without such a component as the high pressure fuel pump solenoid valve.

He is responsible for turning off the engine. If you have problems starting diesel engine, the cause may be the failure of the high pressure fuel pump solenoid valve. To eliminate them, you will need to repair or replace it.

Another reason why a diesel engine does not start is the failure to follow the rules for car care. So that the car runs normally, oil should be changed after a mileage of 7500 km is reached. This is due to the fact that the fuel that is sold at domestic gas stations contains a lot of sulfur. This affects performance, which is significantly reduced.

Diesel engine breakdown prevention

You should also not forget to drain the sediment from the fuel filter and tank. At the same time, if you flush the tank at least twice a year, you can prevent premature clogging of the filters.

Problems with starting a diesel engine can also occur due to improper operation of the fuel system and air filter. Often the banal clogging of these elements leads to the fact that the engine does not receive enough air and fuel. This affects the problems with its launch.

There are many other reasons why there may be problems starting the engine. We have tried to consider only the main ones. We can say with confidence that careful care of their own car will help owners minimize the number of various breakdowns, often caused by their banal inattention.

Any person who owns a car with a diesel engine, sooner or later, may face the problem of starting the engine in cold weather. There can be many reasons for a bad start of a diesel car. Finding a problem and fixing it is sometimes very difficult and impossible without the help of specialists. This review will allow you to get acquainted with the most common cold start problems.

The operation of diesel engines

Before you begin to consider the causes of an engine that does not start well, you should know how it works. After all, a diesel car is different from gasoline versions. Fuel in both gasoline and diesel engines enters through the injectors in its pure form, and air is supplied from the intake manifold, where it mixes with fuel in the combustion chamber. Accordingly, air enters separately, and diesel separately. When fuel enters the cylinders, the diesel begins to ignite as a result of high pressure. It is high pressure that allows such fuel to ignite.

The diesel itself enters the cylinders through nozzles that spray fuel into small particles. Because of this, the fuel burns evenly. In addition, the fuel that enters the cylinders is preheated by means of glow plugs. It is these candles that are used on such cars.

Owners need to understand that even with faulty candles or an inoperative relay that heats the candles, the car can still be started. Spark plugs are just a relief to start the car. Therefore, there are a lot of reasons why it starts poorly in the cold season. Below are all the common causes of car malfunctions.

Compression

The most common starting problem is low cylinder compression. In this case, the car is very difficult to start or not start at all. This is due to the inability of the system to warm up the fuel, which means that the mixture does not ignite.

It should be noted that the reason may lie in the wear of the cylinders, as well as the sealing rings. This problem can only be solved by costly repairs, namely overhaul motor.

Sometimes the engine cannot start normally due to only one cylinder. After starting, the engine will be very cowardly, and strong knocks in the motor can be heard. All these signs indicate a breakdown or failure of one cylinder.

Candles

Glow plugs are another reason why the car does not start well. It is worth noting that in warm weather or a warm car, the owner may not feel problems with candles. With faulty candles, the mixture inside the cylinders will not heat up, respectively, it will be difficult for the car to start.

When the engine is started with faulty spark plugs, problems may appear further. The machine may be unstable and intermittent. If 2-3 candles do not work, then it will be very difficult to start the car on a cold one.

Another problematic start may be associated with a relay that heats up the candles. If the relay is OK, a click will be heard when the key is turned in the ignition. If there is no click, then the problem is in it. When the engine is warm, the car will still start, even if the relay does not work.

Fuel system

In case of malfunctions, starting the car can cause difficulties.

For example, the most common problem is nozzle contamination. In the case when the engine does not start, but goes out of exhaust pipe blue smoke, as well as the starter scrolls through all the nodes, the problem lies precisely in the candles or cylinders.

In order to check the injectors, you need to remove them all from the car. Then, on a special stand, each one is checked separately. It happens that the pollution is partial, which means that the spraying of the mixture is not complete. Then the car starts with characteristic sounds. It starts to “sneeze”, and black smoke will come out of the pipe.

If the nozzles are completely clogged, the starter will scroll through the parts, but nothing will fly out of the pipe. This means that there is no mixture supply to the cylinders.

Problems in the winter

1. Often in winter due to a weak battery. Replacing it will help make it easier to start a cold car.
2. In winter, diesel is waxed. Thus, the fuel turns into a jelly-like substance and clogs the fuel filter. As a result, the car cannot start. To solve the problem, you can use special additives in diesel.
3. Often the reasons for a difficult start are caused by damage to the line through which the diesel engine passes. In winter, such lines may freeze, leak, or cracks may appear in them.

Engine smokes: Diesel | Petrol | VAZ | Blue smoke | Black smoke | White smoke| gray smoke

Compression dropped:A bit| Strongly| completely gone

Smoke: From engine| From the exhaust pipe

BREATHER

At startup

Mechanic's consultation

1. Diesel and benzy new engine bad start

Answer the following questions: Does the engine start poorly "hot" or "cold"? In what state does it start up worse? Does it hold up after running idling? Does it shake or not? Can you hear the glow plug relay clicking when the ignition is turned on? What is the duration between the first, second and third clicks?

A common cause of poor diesel engine starting is poor compression. In this case, the engine does not start well "cold" and a little better "hot", and it does not start abruptly, with an explosion, but "after". Bad compression, in addition to poor engine starting, also causes

several unpleasant phenomena: the engine eats oil, the engine smokes from the breather and exhaust pipe and starts to run unevenly.

The engine is shaking, runs unevenly due to the fact that the reduction in compression caused by engine wear is always uneven across the cylinders.

The engine smokes a bluish smoke of unburned diesel fuel, which, moreover, was poorly atomized. The engine is full of oil drips, since the reduction in compression due to wear causes an intense breakthrough of burnt gases into the crankcase. As a result, pressure begins to rise in the crankcase, since the ventilation system is not designed for too much crankcase gases, and this pressure will squeeze the oil through any gaskets and seals. That's why the engine is in oil. There is also a reduction in power, and high flow fuel, and increased noise, etc. You can somehow put up with all this, but increased consumption of engine oil ... Not only is it expensive to constantly buy and add oil, with a large consumption, it also increases the likelihood that the engine may be left without oil. The main reason for low compression is wear. piston group eliminated by boosters in the cylinders.

Wears out the most the mirror of the cylinder, and the piston rings, as a rule, are fully functional, but they cannot seal the cylinder-piston gap due to heavy wear of the cylinder. Sometimes engines get repaired, in which the step on the cylinder mirror reaches 1 mm. But for many years, repairing Japanese gasoline engines, we have never seen a step on the cylinder mirror in the place where the upper piston ring stops when the piston moves. And you will open a diesel engine - this step is sure to be there. You will say that diesel engines have a higher compression ratio, the load on all parts is higher, and that's the result. Maybe so, but the compression pressure in the combustion chamber is nothing compared to the pressure in the same combustion chamber after a fuel flash.

How to eliminate smoke from an engine

• Why does the engine smoke
• Replacing rings, engine caps
• How to sell a smoking engine
• oil gets into the air filter
• Engine Smoke Additives

• Does not pull the engine
• Troit engine
• Engine stalls
• shakes the engine
• Does not start
• Engine additives

We believe that the relatively rapid wear of the cylinder head in diesel engines is caused by the sulfur content in the solarium. This sulfur, together with water, which is always present in the intake air, forms sulfuric acid, under the influence of which the mirror of the cast-iron cylinder begins to corrode. Fragile corrosion products are removed by piston rings - that's wear. Usually, engines with a mileage of about 100 thousand km, which have just arrived from Japan, have a very small step, and a car will run about 50 thousand km in our country - the wear is already almost limiting.

Based on this, we concluded that this is directly related to poor fuel, or rather, with a high sulfur content in it. When partially dismantling the engine, for example, when removing the cylinder head, wear on the liner can be seen and felt. And then the question arises, is it possible to ride with such wear? We answer it by doing the following. We take the piston ring of this engine and place it in the sleeve in its uppermost part, where there is almost no wear. Just the top piston ring did not reach this place. We measure the width of the gap in the ring, after which we lower the ring so that it is in the place of the greatest wear of the cylinder. Again we measure the gap in the ring. It is known that in a working diesel engine, the gap in the ring lock should be 0.15-1.00 mm. In some models, even 1.50 mm is allowed. But this is the limit. What do we have? Let's say the gap at the top was normal - 0.40 mm. And in the place of development, it became 2 mm, which exceeds the permissible values, and this cylinder must be bored.


Don't have the required compression ring? It is possible to restore cylinders with boosters into cylinders that develop an oxide-resistant nanostructured coating, or you can measure the diameters at the top and bottom. Then calculate the length of the corresponding circles L=3.14 d) and consider the cylinder normal if the difference between the obtained values ​​is less than 1 mm. In addition, you can measure the entire cylinder along its entire length in two directions and compare the obtained data with the specifications for your engine. If you do not have these data, then proceed from the fact that the physical processes in all diesel engines are the same, which means that the limit clearances should be approximately the same. If the engine does not start well, it is necessary to measure the compression, which for a fully serviceable engine is about 30 kg / sq. see. It is easiest to measure compression through the spark plug holes, although you can also turn out the nozzles, and if the diesel engine is in good condition, the compression is above 30 kg / sq. cm, a flash occurs (provided that the nozzle sprays well). For example, we measured the compression of a relatively new 2L-T engine. The first cylinder, the first stroke - 16 kg / sq. cm, the second - 24 kg / sq. cm, the third - a flash, the compression gauge discards, and the pressure gauge with a limit of 35 kg / sq. see rolls over. The second cylinder is the same. And the third and fourth behave differently. On the pressure gauge of the third cycle, 32 kg / sq. see, but no flash. We remove the nozzles, we see that on the first and second cylinders they are "live", and on the third and fourth they frankly "pour". The diesel engine starts quite tolerably when the compression is reduced to 24 kg / sq. see. Boosters can raise the compression even lower: we raised it from 20, but after 18 the diesel stops starting at all.

Pick up boosters You can either by compression known to you, or by mileage or oil consumption.

What happens when compression is reduced? The temperature of the compressed air is reduced, and, in the end, the fuel flash does not occur. If the engine is hot, it is hot outside, the glow plugs are working, the engine can start even at 22 kg / sq. see. When you pull it in tow, trying to start it from a pusher, you simply increase the crankshaft speed, the air from under the pistons does not have time to flow through a poor piston-cylinder seal, as a result, the temperature of the compressed air rises. The same effect can be achieved, however, with the risk of burning the starter, if you apply not 12 volts to this starter, as expected, but 24, i.e. connecting two batteries in series.

1 cylinder in oil

Smoke comes out of the dipstick

A known method of increasing compression by pouring oil into the cylinders of a diesel engine. This is done like this: glow plugs are turned out, and one tablespoon of oil is poured into each hole (if a little more, it’s not scary). Then a rag is thrown on the engine, and the starter is turned on (then make sure that the wire suitable for the glow plugs is not closed to the housing). In two or three revolutions of the engine, all excess oil will be thrown out, and after you put the candles in place and start the engine, there will be no hydrocline, that is, there will be no “sticking” of the pistons. So, if your compression is less than 24 kg/sq. see, the engine needs to be repaired. Only replacing the piston rings will not work, it is necessary to restore the liners. Specialists in factories usually take up their work. The block is bored, a new sleeve is pressed in and the cylinder is bored to fit the size of the existing piston. new sleeve you can take it from some domestic engine, or you can make an iron casting.

After such a repair, if you also fulfill the break-in conditions for at least 10,000 km, you will not have problems starting the car for a long time. Practically, you will have a new engine. The piston (with a connecting rod) into the bored cylinder should fall either under its own weight or from a light push by hand - this must be checked when assembling the engine. Otherwise, it will be necessary to break in the car even longer. With a compression of 24 and even 20, you can easily restore compression to 27 with boosters in the cylinders.

The second reason for low compression- destruction of the piston. The most curious thing is that the prehistory of this breakdown was the same for everyone. The driver fills the car bad diesel fuel, then gets behind the wheel and starts to overtake everyone. Yes, the diesel Crown can move on the highway at a speed of 180 km / h, but its high pressure fuel pump (TNFP) in this case works at the limit of what is possible.

pressure valves

Bodies, springs and pressure valves can be interchanged as you like during assembly. Only copper washers must be used each time new ones or old ones should be annealed: the washer is heated red-hot by a gas burner and, in order to fly off the scale, is lowered into the water. After that, it can be used. The valve itself and its seat make up a plunger pair and cannot be separated.

Poor fuel quality further increases the likelihood of engine failure. Most often, pressure valves start to work fuzzy first. As a result, a too lean fuel mixture is supplied to the combustion chambers, because. part of the fuel is not cut off by the pressure valve, but flies back under the plunger. In addition, the conditions of mixture formation in the combustion chambers at high speed the engines are very bad, and this makes the situation even worse. If we add to all this a limited supply of fuel due to clogged fuel filters, fuzzy operation of injectors and a low cetane number of our diesel fuel, then it becomes incomprehensible how diesels endure all this. The plunger in the leakage ring inclined at about 20 degrees, as well as the cast-iron part of the injection pump, should descend smoothly. Seizures in these nodes were not encountered. If the plunger "thumps" even at an inclination of 30 degrees or more, then most likely it is badly worn. The engine after assembling the pump with such a plunger will not develop full power and it won't start well when hot. If the pressure valve does not work well on Idling, then this is immediately evident, firstly, by shaking the engine, secondly, by detonation knocks in the engine, and thirdly. along the foam that crawls out from under the given union nut of the nozzle (but fuel should squirt).

At working speeds, all these signs of impending trouble are invisible. You continue to move at a high engine speed, a cylinder begins to flow a lean mixture, its piston begins to overheat, and detonation worsens the situation even more. Everything ends the same way: the piston collapses. Compression drops sharply, the cylinder stops working, and the engine begins to smoke with unburned diesel fuel. Then the car comes in for repair. When measuring compression, compression is usually good in all cylinders (and if not very good, then the same), and in one cylinder it is 10 or more kilograms less. The engine, of course, starts, but one cylinder, as a rule, does not work. You start asking how it all happened, and the same thing turns out: poor refueling, driving at high speeds and - a sharp decrease in traction with a white exhaust.

Pressure valve and plunger check

The defects of these nodes are different, but the check is the same. The check valve needle should sink under its own weight into the seat, which is inclined by about 20 degrees. Do this several times, rotating the seat each time you check. There shouldn't be the slightest bite. Otherwise, if the valve cannot be flushed, it must be replaced. We do not do all other checks of valves, since in practice it has been found out that if the valve does not stick, then its cylinder always works without failures, without detonation knocks, and foam does not climb from under the given union nut of the nozzle.

The third reason for low compression consists in the sinking of the rings.

This occurred in two cases: the first - bad engine oil and long parking of the car (more than six months); the second is very bad engine oil. There was such a case. Comes to repair Nissan Largo LD-20-11, "only from the ship." Starts up badly. We measure the compression, it turns out 22-24 kg / sq. see We inform the owner that the engine is on its last legs, and the car leaves. Two days later, the owner calls and says that the car won't start at all. They drag it in, measure the compression, and there it is 14-16 kg / sq. see. This is such a decrease in compression in two days. We are filming valve cover, and the following story of a poor engine is found out. They sold a car in Japan with a good engine condition, and so that the buyer would not have any questions at all, the seller, without hesitation, added engine oil to the top mark of the dipstick. It just so happened that "synthetics" was filled in, and mineral motor oil was added to it and, apparently, a little. The mixture of different oils curled up, and a lot of slag formed, which jammed the piston rings in their grooves. All this happened within three weeks of not very intensive operation, besides, the engine was very good, and the liners of its crankshaft withstood, or rather, did not have time to collapse, and the engine did not rattle, but during the repair they were replaced with new ones, because the wear on the they were more than allowed. Again, the piston ring grooves were not yet broken, which contributed to the occurrence of rings with very bad oil. The following should also be said about the sinking of oil rings. For the winter, the owner fills the engine of his car with all-weather oil SAE 7.5W-30. For winter Yekaterinburg, in general, quite a good choice. But severe colds come (-20 degrees C), and it turns out that the car starts up very badly in the morning. Although it will stand for a day under the window and in the wind, it starts up well, but during the night, at the same temperature, the engine becomes inoperative. We took and measured the compression of this diesel engine in the morning, right in the parking lot. It turned out to be 10 kg / sq. see that is clearly not enough to run. When the engine was still started and warmed up, its compression was more than 24 kg / sq. see, and it started confidently. The cranking speed of the starter when measuring compression in both cases was the same by ear. Apparently, the reason for this phenomenon was in the old engine oil or its poor quality. In any case, the 7.5W declared on the packaging was not provided. All engine oils wear out their additives, including additives that provide low viscosity in the cold state. And when you have, for example, SAE5W-30 oil filled in, this does not mean at all that after 5000 km it will remain the same. Due to wear and bad conditions, it may have gradually turned into SAE 10W-30. By bad conditions, we mean this. All users of industrial diesel engines, for example in the navy, choose their engine oil based on the chemical analysis of the fuel used. In other words, oil is selected for fuel. What fuel is used in our diesel cars? The one you fill up at the gas station. And no one knows how the engine oil you bought fits this fuel. This is the first.

Secondly, we ourselves add various dehydrators to the fuel to remove water. How these dehydrators affect additives is unknown. You can name another third, fourth - all this will be "bad conditions." And as a result, even good oil ceases to meet the standards indicated on the packaging, but this happens gradually. Therefore, it may turn out that, after pouring SAE7.5W-30, after 2000 km you will have SAE 15W-30 in the engine, and the piston rings during a cold start will not be able to constantly "play" in their grooves, eliminating the piston-cylinder gap, especially if there is already wear. Thus, we have, as it were, the sinking of the rings, which goes away with the engine warming up. And until the engine warms up, there will be no good compression. A cold engine is easy to start after applying boosters to the cylinders.

These are the three most common causes of low compression. Of course, there were other reasons for the reduction in compression, such as a bent connecting rod as a result of a hydrocline (the car drove over a puddle), a burst gasket (the guys drove for a month with a broken gasket, adding water), valve depressurization (valve seat fell out), and for some reason all three times this happened with the Toyota 2L-T. But in these cases, they usually do not say that the engine does not start well. Yes, because of the low compression, it does not start well, but the reason for the visit to the auto repair shop is usually indicated, however, is different: the Tosol kicks out, there were knocks in the engine, etc.

Second common cause of startup failure- malfunctions in the glow plug control system. Everything is easier here. It is necessary to take out all the candles, tie everything with wire and fix it to the ground. Pay attention to the fact that when the ignition is turned on, all candles heat up exactly the same. If any spark plug heats up differently than the others, it must be replaced.

The fact is that during the heating process, the internal resistance of the candle changes, and its value is taken into account in the control unit and affects the warm-up time. If your engine is equipped with double plugs (the Nissan LD20-II engine has regular glow plugs on the first and second cylinders, and plugs with two positive leads are installed on the third and fourth cylinders), then check their identity by first applying voltage to one bus, and then to another.

Candles, or rather, a garland of candles, can be checked on the table from a separate battery. So, you have learned that your glow plugs heat up to the same color, which means they are all working. There is no such thing that all four (or six) glow plugs are equally bad, always one or two will be worse than the rest. But they can be just as good. Now, to find out if your glow plug system is working, you need to do the same check, but on the engine. It's a little more difficult, but possible.

Connect all glow plugs to a common tire (or tires if there are two), but so that they stick up. With a thick wire, make a mass for each (!) Candle and connect the power wire (or wires). After that, with the help of rags, exclude the possibility of touching the positive terminals of the candles and the tire with the engine housing. Then one person gets behind the wheel, and the second looks at the candles and listens to what the first one will shout to him from the car. The first one turns on the ignition and shouts: "Turned it on!" - then monitor the spark plug control lamp on the instrument panel. When it goes out, he shouts: "Got out!" - this is where his work ends, while the second person, more experienced (we hope that it will be you), watches the candles and listens. If the system is OK, the following will happen. After shouting "Turned on!" under the hood, several relays will click loudly and simultaneously, a light smoke will come from the tips of the candles (if you had clean hands when installing the candles, there would be no smoke), and the candles will start to warm up. By the time the cry "Got out!" is heard, the candles should be cherry, while continuing to warm up. And now, when they turn red, the relay will click, and the 12 Volt power will be removed from the candles, i.e. the accelerated heating of the candles will stop. But they will remain red, because they are still given a reduced voltage of about 5 volts.

However, for cars of some companies, such as Mitsubishi, the second stage of heating is turned on only when the engine rotates from the starter or by itself, that is, it works. It may take about a minute or more until the low voltage from the candles is removed. This will always happen if the candles and their control system are working. And what can be, or rather, what happens most often when there are problems? And the following happens. Joyful "turned on!" - and immediately overlapping: "Got out!" - and under the hood: click-click. This is a glow plug control unit (or a timer, or a controller, or an ECU, etc. (turned on the candles, turned on the control lamp and immediately decided that enough was enough and turned everything off.

The reasons are as follows: 1. Glow plugs do not meet the requirements. 2. Faulty engine temperature sensor (or engine hot). 3. The timer is faulty.

Most often, of course, there are problems with candles. The market is flooded with glow plugs for all engines, but these plugs, made in third countries, are often of extremely poor quality. Not only do they initially do not quite meet the requirements for the magnitude of internal resistance, they also fail for a period that is obscenely short. But such candles cost only about $ 10, while double candles made in Japan cost about $ 60 or even more. When controlling candles, the timer, among other things, takes into account the temperature of the candles by their resistance, and does not allow them to heat up above 1000 degrees C.

When heated, the resistance of the candles increases, and the current consumption decreases. But when one glow plug burns out, the total resistance of all glow plugs (in terms of the timer) also increases. And two cold candles create the same load for the timer as four red-hot candles, and he decides that they should be turned off immediately. Naturally, the timer also takes into account the temperature of the engine. Diesel engines contain several temperature sensors, so finding a sensor for a timer is quite difficult. The sensors are as follows: a temperature sensor for the instrument panel, a temperature sensor for the automation of the "climate control" unit, a temperature sensor for turning on the radiator cooling fans, a temperature sensor for the automatic gearbox control unit, a temperature sensor for the engine control unit (EFI diesel) and a temperature sensor for the spark plug control unit. Here's what you can suggest. The temperature sensor for the instrument panel always has one output, and when the wire is removed from it, the readings of the device change, the arrow falls. The climate control sensor also has one output. The rest of the sensors, as a rule, have two outputs. By removing the sensor connectors one by one and shorting them through a control light to the case or to each other (if there are two outputs), but also through a light or a resistance of about 200 Ohms, you can find out how certain blocks behave and find out where which sensor.

Very often, the temperature sensor of the timer for Mitsubishi diesel engines fails. It is located on the block head in the front left part of it. This sensor has two flat leads at an angle of 90 degrees. Usually, when it breaks down, after starting the engine, the relay for controlling the secondary glow of the candles starts to click loudly. The clicking stops when the engine is fully warmed up. If you remove the connector from the sensor, the clicking will stop. In conclusion, I would like to draw your attention to the fact that, no matter what state the engine is in (hot or cold), it will not start (at least as expected) until the glow plugs are red. Therefore, when the engine does not start well when hot, it is also worth checking whether the candles are heating up. In any case, if the glow plugs turn off before they heat up, and there is no way to replace them or replace the timer (if it is to blame), this is what you can advise. Disconnect the control wires from the candle switch relay and connect your wires, through which, using a separate button, it is powerful to send a signal to turn on the relay, and therefore turn on the heating of the candles. You can connect one wire to the car body, and on the other, use the button to apply only "plus". But if you are "friends" with electricity, then you can do it even more tricky. First, find out how the relay is controlled: by the supply from the "minus" timer (then the "plus" is supplied after the ignition is turned on) or vice versa.

After that, leaving all the regular wires in place, connect another wire with a button in the cabin. Now the timer regularly heats the candles (turns on the relay), but if, under some temperature conditions, it does not warm them up enough (and you will determine this when, by removing the candles and "tying" them together, check how they heat up during the exposure time from the timer) by pressing the button, you can slightly increase the warm-up time. Just do not forget to install a decoupling diode just in case, otherwise you never know what the voltage from the button, forcibly applied to the timer output, can do. You can, of course, apply the plus button directly to the candle power bus, but in order to provide high current for the glow plugs, you will need thick wires and a powerful button. And in all cases, you run the risk of overheating the glow plugs, after which they will burn out.

Another problem with engines is:

In a cold state, it starts up more or less decently, and when it warms up - that's it. Either it does not start until it cools down, or it starts, but with great difficulty. Sometimes the reason lies simply in a dirty starter. The starter must be sorted out, cleaned, replaced, if necessary, bearings, lubricated and reassembled. Then he will be able to make a powerful breakthrough to start the diesel. Many car owners, when asked how the starter of their car turns the engine, answer: "Yes, it's fine." And in the morning, in a cold state, and in a hot state. But "normal" is both 150 rpm and 200 rpm. In the first case, the engine is unlikely to start, and in the second, it will start. By ear, 130 rpm are quite normal, but will the engine start at the same time? In addition, the starter turns the engine not evenly, but in jerks, but is it possible to estimate the rotation speed by ear at the moment of a jerk? Therefore, the starter system should always be carefully checked, not trusting the assessment by ear. But there are more complex reasons.

When the plunger pair in the injection pump is worn out, cold fuel is still somehow pumped by the plunger, but when it warms up a little, it becomes more liquid and is no longer supplied in the required volume. The point, or rather, wear, comes to the point that 10-15 minutes after the owner started the car in the morning and drove off, it begins to reduce its power. After 30 minutes, if you do not press the gas pedal, it will stall and will not start until it cools down. The duration of the process depends on how soon the engine warms up, how hot it is outside, what load the engine will be given, and how worn out the plunger pair is. Take a look at the table. This data is for Toyota 2L and 3L engines. If you have a different engine size, for example, 20% lower, respectively, and the values ​​of all fuel volumes will be lower.

The largest volume of injected fuel occurs at the injection pump speed of 100 rpm. The engine at the same time has 200 rpm. The fact is that at these speeds the centrifugal speed controller does not yet work, and the high-pressure fuel pump gives out everything it is capable of. So, a car comes with a Nissan LD-28 engine. Cold starts, hot doesn't. It will stand for about 3 hours, cool down - it starts up again. But if, during the “hot” start-up, something is sprinkled into the intake manifold from an aerosol can, just to burn, it immediately starts up. It doesn't matter what the can is filled with: WD-40 grease, Unisma, carburetor cleaner, as long as it says "Flammable" on it. We connected the tachometer, found out that the cranking speed of both the cold and hot engines are the same. This was audible as well. Remove all glow plugs and one injector. We check on the stand - it works. The cut-off, however, is bad, it pours a little, but in general it works for three plus. We bend the fuel supply pipe of the removed nozzle, screw on the nozzle and substitute any container. Then one person starts to turn the engine with a starter, and the second one counts the "zilch" of the turned off nozzle. We do not install the overflow line during this check, so the cut-off fuel simply pours out, but there is very little of it. After 50 cycles, we stop turning the engine and, using a disposable 2 ml syringe, measure the amount of fuel pumped through the nozzle. We got about 0.8 ml. They gave the engine an hour to cool, they all repeated - it turned out 1 ml. After that, they waited another hour, and even poured cold water on top of the high-pressure fuel pump, it turned out 1.2 ml. Judging by the table, this is not enough, but after assembly, the engine started up (while it was being assembled, it had cooled down a little). However, in the table, the data is only for the pump, without the nozzle. With a nozzle, the figures would be slightly lower (part of the fuel will go to the overflow line, but this is not more than 20%). Conclusion - it is necessary to change the injection pump. Rather, it is necessary to change the plunger pair, but no one sells it separately. So, we need to look for any high-pressure fuel pump from a six-cylinder VE type engine, albeit slightly broken, but with a working plunger pair.

Another case from practice, this time with a Toyota 2L-TE engine in a Toyota-Crown. As the name suggests, this is an EFI diesel. It started up in a hot state, but “after”: for about five seconds the starter rotates the engine, there are no flashes, then the engine gradually increases, increases speed, more and more, and you continue to hold the starter, and, finally, the engine picks up and starts. On a cold engine, everything is the same, only much longer. The owner turns the engine for a whole minute, it seems to be working, but as soon as the ignition key is released, it “dies” immediately, although it had almost started up before that. The reason, as it turned out, was also insufficient injection volume, but the control valve was to blame. Of course, you remember how a conventional injection pump works: the plunger compresses the fuel, and it is forced through two channels. One channel eventually comes to the nozzle, and the second dumps fuel back into the injection pump. But it dumps through the hole, which is blocked by a leakage ring. By pressing the gas pedal, you move this leakage ring, while adjusting the amount of fuel injected into the cylinders. In addition, the movement of the leakage ring depends on the position of the weights of the centrifugal speed controller, on the pressure inside the high-pressure fuel pump, on the position of the diaphragm of the compensation mechanism (in the mountains, this mechanism crushes fuel, on the plain - no, when turbocharging it increases fuel supply).

In the electronic injection pump, all this is not there, the fuel discharge channel is blocked by a powerful plunger solenoid valve. This valve receives an electrical signal from the control unit (EFI unit, computer). This signal is a complex sequence of pulses (preparatory, starting, equalizing), the frequency of which depends on the engine speed and operating mode. Even the temperature of the fuel in the injection pump housing is taken into account. A little wedging due to wear in this valve created all the problems. Quite quickly (in two days) we managed to find a defect, due to the fact that another car came for repair, a Toyota Surf with a faulty automatic transmission, which has the same 2L-TE diesel engine, but it works fine. Subsequently, the problem of low power in such machines was solved by us simply: they replaced the valve, and the engine worked normally. The owner of the first car noted that after the repair (replacement of the injection pump), the car began not only to start well, but also its power increased. During the repair, it turned out that there are several modifications of electronic injection pumps, and the valves on them have different threads. When we encountered this, we dismantled two injection pumps and assembled one serviceable one from them. A few more words about the electronic injection pump. From the bottom it has a valve that bypasses the fuel pressure under the injection advance control piston, from the top on the cover there is a speed counter (there is another one, in front, near the high-pressure fuel pump shaft), on the side there are two sensors that count temperature and pressure. Moreover, removing the connectors from these two sensors (they different color and fixed outside the injection pump housing) does not cause any noticeable changes in the operation of the engine. On older injection pumps, there may be a cut-off valve (silencer), in the same place as on mechanical injection pumps, but only on the side face.

There is a knock sensor on the engine block, when the connector is removed from it, the injection moment immediately changes, as can be seen from the increase in speed and clanging during diesel operation.

There is also a flash sensor on part of the engines in the head of the block, but we did not have to experiment with it. To summarize the above: what are the causes of poor starting diesel engines? The engine will not start because it does not have a fuel flash. This can happen either due to insufficient temperature in the combustion chamber, or due to the fact that there is simply nothing to burn. And there is nothing to burn because the injection volume is small or the fuel is supplied at the wrong time, although in the required volume, so that at the moment the piston passes the top dead center in the combustion chamber it is not. For example, if the injection is too late (there is enough fuel), it is carried out when the piston is already lowering and the temperature in the combustion chamber has dropped.

Such a malfunction as a hard start of the engine is also widespread, we call it "starting after". The engine rotates at first without flashes, then rare flashes begin to appear, which become more and more frequent, and finally, the engine picks up and starts working. The root cause of this is that only one or two cylinders are involved in starting the engine. In the remaining cylinders, when the engine is rotated by the starter, there are simply no conditions for a fuel flash.

Why is it in one cylinder and not in the other? Fuel will ignite only when it is heated. Suppose the compression of the "seizing" and "dead" cylinders is the same, which means that the temperature in the combustion chamber at the end of the compression stroke will also be the same, of course, provided that the glow plugs are heated to the same temperature. But whatever the temperature in this combustion chamber, there will be no flash until the fuel is heated. When it is in the form of a mist, it will heat up instantly, but if it is in the form of drops? So the nozzle tried (even ideal nozzles, working on our fuel, remain ideal only for a few hours). Probably, you have observed clouds of gray smoke in the mornings after starting a diesel car. This is the unburned droplets of diesel fuel. No matter how new and branded the nozzle may be, it will not succeed in turning the entire volume of fuel supplied into a homogeneous fog. The engine warms up, the temperature in the combustion chambers "slightly" rises (by a hundred degrees), the fuel droplets have time to burn out, the car stops smoking. If the engine is not worn out, i.e. its compression is high, then the temperature in the combustion chamber will be high, much higher than the flash point of the fuel; in this case, the droplets will have time to warm up and burn out immediately after starting the engine. If the compression is insufficient, but still within the normal range, the engine may also not smoke, but only when it is fully warmed up, i.e. when the lack of temperature from compression is slightly compensated by an increase in the overall temperature. In addition, even solar oil drops can flare up if there is enough time for this, i.e. if there is an early injection with all the "charms" of the hard work of a diesel engine. Many owners of diesel cars, tired of watching clouds of smoke around their pet in the morning, slightly turn the injection pump towards rotation and thus slightly increase the injection advance and reduce engine smoke. Most often, from this operation, the engine only gets worse, but there are cases when, by turning the pump, the owner gets to the point.

The fact is that in the process of wear of the high-pressure fuel pump drive mechanism and the pump itself, a gradual misalignment of the fuel injection timing occurs. And always this misalignment goes in the direction of injection delay. By turning the injection pump to an earlier injection, you compensate for the existing wear and the engine runs normally. But turning the injection pump to optimize injection timing makes as much sense as turning the distributor to optimize ignition timing. And if the ignition timing vacuum servomotor does not work in the distributor or the centrifugal machine is jammed? By turning the distributor you will improve engine performance, but the malfunction will remain and in some engine operating modes it may not appear. in the best way.

The same can be said about the rotation of the injection pump: if you turn the pump, because the injection advance system does not work as it should at certain speeds, and if the advance system works at high speeds, and the rotation of the injection pump is superimposed, then as a result, at these speeds, the engine there will be an early injection. You may not notice this because of the noise of the engine, and your engine pistons will be left "one on one" with detonation. Whether they will survive it and how long they will survive is unknown. Diesel engines may also have such a disadvantage. The engine runs smoothly at idle, you press the gas pedal - it continues to work smoothly, and suddenly shaking appears at some speed. Clubs of blue or gray smoke fly out of the pipe, and then they added speed - everything is fine, there is no smoke and shaking. Possible shaking at idle.

The reason for this has so far been the same: sticking of the injection advance mechanism. During the operation of the engine, the roller ring in the high-pressure fuel pump constantly fidgets in the same place, adjusting the fuel injection advance, while there is a development on the pump housing, which contributes to wedging. The second option is the development of the piston cylinder of the timer-distributor. Here, the loads are smaller, but the entire mechanism is located below, where debris and water constantly accumulate, which contribute to the wedging of the piston. We recommend loosening the fastening of the high-pressure fuel pump and turning it a little to an earlier injection, literally by 2-3 degrees, and the defect will disappear.

The next widespread reason for repairs is a black exhaust. Most likely, nozzles are poured, and poorly mixed fuel does not completely burn out. Pour - this is when, after closing the shut-off needle, fuel is still pouring from the atomizer, completely relieving pressure in the nozzle. Every second auto mechanic will tell you that the nozzles need to be compressed, but he will only be partially right. Compressing means removing the nozzle, installing it on a stand and using a hand pump to pump fuel through it several dozen times. Since the fuel is pumped in very large portions, much more than when the nozzle is running on the engine, all possible debris is washed out. At the same time, the atomizer needle rises very high (compared to regular operation) and sits down with great force, slamming the seat.

This operation, as well as complete disassembly and cleaning of the entire nozzle, does not always help. No cleaning will help a heavily worn atomizer. True, sometimes it is possible to grind the plunger pair, or rather, the locking belt, with the help of grinding paste. But it takes a lot of time, and it is not always possible to achieve a 100% positive result even with very careful work. Unfortunately, even new sprayers do not work well in 50% of cases. A working nozzle should be clearly cut off. This means that when you gently but intensively press the fuel pump lever, the nozzle should spray a cloud of diesel fuel not continuously, but in frequent portions. At the same time, a sound is heard similar to firing from a machine gun with a silencer, only even sharper. This is one of the main indicators of a good nozzle. If there is a cutoff, then the nozzle will not pour, and its cloud, as a rule, is symmetrical.

Diesel injection pressure

The volume of injected fuel also depends on the injection pressure. For each nozzle of any engine, this value is determined by the thickness of the metal shim located above the spring. If it is ground off by about 0.08 mm, the injection pressure will decrease by 10 kg. The injection pressure of new injectors is about 5-10 kg higher than that of used ones, which is due to the aging of the spring. When replacing nozzles with new ones, the pressure of the nozzles either does not change if it was normal, or rises to normal if it was underestimated. Of course, there are exceptions, which are associated with deviations in the technological process in the manufacture of nozzle parts. Some injection pressure values ​​for Japanese diesel engines are shown in the table. But we have seen diesel cars with low injector opening pressure, the owners of which were quite satisfied with them: the Mark II with a 2L-T engine had an injection pressure of barely 90 kg/sq. cm, and, although the engine smoked slightly, the owner was delighted with him: "... give it gas - and immediately 160 km / h." Of course, black exhaust can be caused not only by the fact that the nozzles are "pouring", although, as already mentioned, this is what happens most often. Not completely burned fuel in the form of black smoke flies out even with a lack of air. For example, you have a clogged air filter (not an uncommon cause of black exhaust) or a bad turbine. Yes, after all, you may have fed so much fuel into the cylinders that it simply does not have enough air to burn out. For example, they pressed the gas, but the engine has not yet spun up and it still does not have enough air. The air has some inertia, and the high-pressure fuel pump immediately delivers fuel "to its fullest", so even new diesel engines have blackness in the exhaust when accelerating. In other words, in order to change the speed of diesel engines, first of all, they increase or decrease the fuel supply, and how much air is sucked in, how much is sucked in. In gasoline engines, which do not smoke during acceleration, air is first sucked in, and then, under this air, fuel is supplied by a carburetor or injector.

When the diesel engine is overloaded, when its speed is low, the fuel goes with the maximum supply (after all, you put pressure on the gas), and the centrifugal regulator does not limit this supply yet (the engine speed is low), the fuel mixture is also re-enriched and, as a result, black exhaust. The ability of diesel engines to smoke under certain operating conditions and the need for protection environment led to the appearance of diesel engines with throttle valves, their position sensors, various exhaust gas return systems (ERG) and, ultimately, to the appearance of electronic injection pumps (EFI diesels, for example, 2L-TE). On the other hand, the appearance of smoke in some operating modes for serviceable engines (this does not apply to EFI diesel engines) makes it possible to determine whether the fuel system has sufficient capacity. For example, a clogged fuel filter prevents the injection pump from delivering large amounts of fuel in the first place during overload or acceleration, and there will be no black smoke. But there will be no power from the engine. There is a direct relationship: there is no black smoke when starting off sharply - there is no power either. And most likely, due to the fact that the filters that clean the fuel are clogged. However, it should be noted that the effect of a clogged fuel filter: the absence of black exhaust in some modes; a decrease in engine power, and with cold fuel, in the morning, a decrease in power is more significant than with warm fuel, in the afternoon, also causes air to leak into the fuel system. In any place before the high-pressure fuel pump, air leakage can occur through various leaks. And a noticeable fuel leak will not be visible, since there is permission everywhere and all the time. The engine is running - permission from the supply pump, standing - permission because the fuel tank is below any element of the fuel system and everything flows into it. Most often, air leakage occurs through leaks in the fastening of the fine filter, through the rolling of the manual fuel priming pump and, less often, through corrosion holes in the metal fuel line. The place of air leakage can be seen from the fact that it "sweats" a little, but no more. When air enters the injection pump in small quantities, nothing bad happens, it is immediately expelled in the form of foam through the "return". When it is a little more, part of the foam falls under the plunger, and the fuel supply is limited. If the strainer is clogged in the bolt that secures the "return" pipe, even a small amount of foam can disrupt the operation of the high-pressure fuel pump, because she does not have time to go all into the overflow line ("return"). It is very easy to determine if there is an air leak, it is enough to replace an ordinary rubber tube in the fuel line with a transparent PVC one and start the engine. You will immediately see the existing air leakage by the bubbles moving along with the fuel in a transparent tube.

If in December you received a car delivered from the hot south of Japan, the next problem lies in wait for you. Summer fuel poured somewhere there freezes during our frosts, and the formed ice crystals and pieces of paraffin clog all filters in the fuel system, after which diesel fuel is not supplied to the nozzles. In winter, when such machines are unloaded from the steamer, they can be saved by spending the night in a warm garage, refueling with winter fuel and adding some kind of dehydrator-fuel system cleaner to the tank. If you're lucky, there won't be any more problems, and if not... They drag two handsome Nissan Safaris with TD-42 from the customs warehouse on a rope. Both dead and batteries too. In the yard - minus 15. We charge the batteries, unscrew the glow plugs, start cranking the engine - no reaction: there is no solar column from the candle holes. We pump with a hand pump - it does not swing. It's not that it fails hard, as it happens when the high-pressure fuel pump is full, but in general, the button "is worth a stake." We unscrew the bolt on the injection pump housing, which secures the inlet pipe, the pump pumps perfectly. We recall that Nissan always has a filter mesh at the inlet, we take out the spring fixing it and the mesh itself (the bolt was unscrewed earlier) and we see that it is all clogged with paraffin and ice. They blew it, put everything back in place, checked that the hand pump pumped the injection pump (it was tight, but it pumped), and began to crank the engine. Jets of solar fog immediately began to fly out of the candle holes - everything is fine. We put the spark plugs in place and pumped some fuel through the injection pump again before starting. It should be noted that both Safaris were repaired in parallel, by two mechanics who approached the last upgrade at the same time. And then it turned out that when pressure was created with a hand pump from the lower plastic plug of the fuel filter in one of the cars, fuel flows through the crack. This crack, apparently, appeared when the water sludge in the filter plug body was frozen, and while all this fuss lasted, about an hour passed, the sludge melted and the filter dripped. Both cars started up easily, the first one famously turned around and left, and the second one somehow (the engine does not keep speed, strives to stall) drove out into the yard to suck, to wait until a new bottom plug was brought for it (and at the same time a new filter). After replacing the plug, the TD-42 worked confidently. If you constantly operate your car with an incomplete fuel tank during the winter, the following may occur. Due to temperature fluctuations, frost will form on the inner walls of the fuel tank. If it thaws, and a few drops of water get into the fuel, nothing bad will happen. Water will fall to the bottom, and if there is already a lot of it (about a liter), it will partially enter the fuel line and linger only in the fuel filter sump. When the sump is full, a float will pop up in it and turn on the water control light in the filter on the instrument panel, so that you know that you need to drain the sludge immediately, since if water gets into the high-pressure fuel pump, then there is a high probability of its failure (the plunger will break, For example). If the frost falls into the tank in the form of ice crystals, then these crystals will not sink to the bottom and can easily get into the fuel line and through it to the fuel filter. Bandwidth as a result, the filter will decrease up to its complete blockage. From the foregoing, it follows that water, especially in winter, in the form of ice floes that do not sink, is serious enemy diesel fuel system. It is necessary to fight it by regularly draining the sludge from the filter and periodically adding dehydrators to the fuel, i.e. additives that remove water.

2. Low power. Low power is another "headache" for owners of Japanese diesel cars. Power reduction by any driver is defined by the term "not driving". But this can be the result of various reasons: from flat tires to malfunctions in the automatic gearbox, when, for example, the gearbox does not turn on the first speed, but starts off from the second, which is also perceived as "the car does not drive." When to our company, which is mainly engaged in repairs automatic boxes gears, a car arrives, the owner of which complains about the operation of the automatic transmission, the first thing we do is conduct a "parking test". On a warm car, the brake is clamped with the left foot, and the gas pedal is depressed to the stop with the right foot (when the "D" or "R" position is on). After that, the readings of the tachometer are read. Tachometer readings less than 1800 rpm indicate insufficient engine power or a defect in the fluid coupling. But the latter is very rare on Toyota vehicles with diesel engines and 3S and 4S engines. Usually in these cases, the car starts off badly and does not go uphill, and when it reaches a high speed (about 100 km / h), everything is fine, i.e. the engine is powerful enough and easily accelerates further when you press the gas. It is very difficult to determine on your own why the car does not drive, because of the engine (low power) or because of the machine (the splines of the guide vane in the fluid coupling were cut off).

Often there are disputes between teams of "machine gunners" and minders, who will repair the car. If the engine speed is from 1800 to 2200 rpm, then everything is fine. If more, then the automatic transmission, most likely, is already in need of repair, although not everything is clear here either. This test leads to a large heating of the oil in the fluid coupling, so it must be carried out quickly, no more than five seconds, then let the engine run for 1-2 minutes and carry out the test further or turn off the engine. In auto repair shops, quite a lot of parameters are checked using the "parking test", and it can be carried out 2-3 times in a row. For vehicles with mechanical box There is no "parking test" gear, and the only way to determine if it has enough power is to compare it on the highway with another car of the same class and displacement. For example, a Toyota Town Ace with a 2C-T engine on the rise should not noticeably lag behind the Nissan Largo LD20-IIT. If one of the cars is noticeably "dumberer" than the other, then you should roll one slightly on even asphalt with your hands, and then the other. If the cars have different rolling, for example, due to different type rubber or tire pressure, you will immediately feel it. At the same time, check whether the wheels of these cars are equally heated, maybe there is some kind of problem in the hubs, or the brakes are wedged. If all checks indicate that the poor dynamics of the car is caused by a decrease in engine power, then you should start diagnosing it. Very often, cars come in for repairs, the owners of which complain about the low power of the engines, and the reason for this is surprisingly simple. You will ask the owner to sit behind the wheel and, without starting the engine, fully press the gas pedal and hold it in this position. After that, you take the lever of the fuel pump with your hand and turn it even more. And it turns out that the gas pedal is fully depressed, the gas cable is fully taut, and you can still add gas by hand, that is, it turns out that the gas cable is not adjusted correctly. And the whole repair is to adjust the cable. The main reason for the reduction in power in diesel engines is the restriction of fuel supply. There is an air leak, and a frozen fuel pipe, but most often some kind of fuel filter is clogged. The maximum number of fuel filters in a diesel engine that we have seen is six. Most drivers are probably unaware of this. Whether all filters are in good condition is easy to determine by doing a "parking test" for the car, but only for "automatic machines". As already mentioned, you cannot do this test with a manual transmission.

All this can be done without removing the pump, directly on the engine, by dismantling only some pipes, hoses and harnesses. Before unscrewing the shut-off valve (we call it a "silencer"), remove the rubber cap from it and, unscrewing the nut, remove the control wire. It is necessary to take out the jammer carefully, since a spring and a core with a locking rubber band at the end can fall out of it. The sealing rubber ring (toric) should not be lost either. If all this remains in place, then by removing the jammer solenoid itself, you can remove everything else with tweezers. Solenoid valves for fuel cut-off (silencer) on all high-pressure fuel pumps, regardless of which engine model and brand they are installed on, have the same design and the same dimensions (at least it was so far). In relatively new high-pressure fuel pumps, under the muffler, at the bottom, a multilayer filter mesh is installed, but it is better not to touch it yet. You should blow compressed air into the side hole through which fuel enters the shut-off valve. Fuel through a multilayer mesh (if any) then flows through the central hole at the bottom of the "hole" (from where the cut-off valve was turned out) further into the plunger pair. When you blow into the side hole, the air must go out somewhere, and in order for this air to flow powerfully, it must be provided with a free exit. To do this, we unscrew the bolt that secures the fuel inlet pipe, and the bolt that secures the overflow pipe. As already noted, the head of the latter has the inscription "OUT", and in its body there is a strainer. Before reinstalling this filter, without removing it from the bolt, it should be washed again with an aerosol cleaner for carburetors, and then blown with compressed air. When both bolts are removed, you will make 10-15 powerful strokes with a hand pump (if you do not have a compressor and you will use a hand pump to blow out) into the side hole. Most likely, you will be blowing into the side and center holes at the same time, because. it is quite difficult to make a special adapter in order to blow only into the side hole. But at the same time, nothing terrible will happen, since the central hole leads under the plunger space, and everything there is designed for such pressure that you can’t blow through anything. But along with the air, you can bring garbage there, so you should not remove the multilayer mesh before blowing. When blowing, you will see that compressed air with diesel fuel flies out through the "return" hole, so after 6-8 strokes, cover the overflow line hole with your finger and squeeze the air-fuel mixture through the inlet with the rest of the strokes. Now you can remove and clean (with a cleaner and compressed air) the multilayer filter mesh and then put everything back in place. The main goal of this entire simple operation is to discard, and perhaps partially remove with air all the debris from all available fuel filters in the injection pump housing. After such a purge, three scenarios are possible: 1. The power increases and no longer decreases, the conclusion is: there was dirt in the pump, and you were lucky, you blew it out. 2. The power increases, but after a few weeks it drops again, which means that there was dirt in the injection pump, but you were unlucky, it remained, you could not blow it out, the pump must be removed and everything in it cleaned. You can, of course, try to repeat the purge, in the hope that this time you will be lucky. 3. Engine power has not increased. Conclusion: it's not about clogged fuel pump filters, the reason for the restriction of fuel supply must be sought elsewhere.

But still, most often it fails, i.e. clogged, fuel fine fuel filter. Replacing it with a new, "branded" one will not necessarily solve all problems. Example. A Nissan Safari car with a TD-42 comes to repair the automatic transmission (the owner himself made the diagnosis) - they say, it does not go. Our boss gets behind the wheel, on the spot, conducts a "parking test" for three seconds and immediately assigns the car to a team of minders: the tachometer was 1600 rpm. They offered the owner to replace the filter, he claims that he only changed it yesterday. Changed, so changed. We approach the car, and it has an idle speed of about 700 rpm. They began to pump up fuel to it with a hand pump, the idle speed rose by about a hundred. Continuing to pump fuel, we carry out a "parking test", the result is 1800 rpm. There is an obvious lack of fuel. Since the car is expensive, and we don’t need returns, we removed and dismantled the high-pressure fuel pump for it in order to clean everything there. We knew the TD-42 had a strainer at the inlet, and apparently it was clogged. But the same defect can also occur when one or two blades of the booster pump in the high-pressure fuel pump are jammed, and when the mesh at the silencer inlet is clogged, therefore, for reliability, the entire pump was sorted out and cleaned. They did everything, they did not find any special defects in the injection pump.

The only serious defect is a clogged mesh at the entrance. The car left with a happy owner. It takes three days - appears again. The problems are the same. We take out the mesh - it is clogged again. Using a binocular, we determined the composition of the garbage: small villi from the filter element of the fine fuel filter. Again, we suggest the owner to change the filter. And he: "So I changed quite recently." When he came to us for the fifth time in two weeks, he had already brought a new filter. After replacing the filter, the visits of this car to us stopped. Why did everything happen? Most likely, the filter installed for the first time was of poor quality, and the villi were torn off from its element by the flow of fuel, with which the mesh was clogged. The second version: water got into this filter and some of it remained on the filter element. In fact, the water in the filter should have rolled down and ended up in the sump, but, being associated with dirt (rust), it remained in the form of a slurry on the filter element. Then the frost, the water freezes, tears the filter element, the villi from it sweat and clog the mesh. In general, it should be noted that after installing a brand new fuel filter, it is enough to “successfully” refuel once in order to change it again the next day. Therefore, the phrase "the filter is good, I changed it only a week ago" makes us smile sadly.

You can check the condition of the intake screen and the fine fuel filter very quickly. if you have a booster pump (in the form of a button) located above the filter housing. First, drain the sludge. If there is water there, then, as practice shows, the filter is already half useless. Secondly, on a running engine, press the button several times, pumping up fuel in this way. In this case, an increase in engine speed XX will indicate a lack of fuel supply. When pressing and releasing the pump button, pay attention to the speed with which the button, under the influence of its spring, returns to its place. After that, spin the engine up to 4000 rpm and pump up more fuel. If clogged, the button will return more slowly or retract at all, and it will not return to its place.

There is another reason for insufficient power. For example, Toyota Cruiser drives around Japan and slowly wears out. Her injectors were worn out and began to spray fuel poorly. The car began to smoke a little. It can be repaired, but it is better to sell. And who will buy it if it smokes? The easiest way is to break the seal on the screw for coarse adjustment of the fuel supply and "crush" it. After that, it is enough to restore the idle speed, and the car does not smoke black smoke at all. But he doesn't drive either. When such a car comes in for repair, the adjustment is returned to it, and it starts to smoke. This means that it is necessary to repair the nozzles (or replace the sprayers in them), turn the injection pump by 1-2 percent to early injection in order to also compensate for the wear in the pump mechanisms, the timing belt exhaust, gear wear, etc., and the car will drive like necessary.

Jamming due to rust of the distributor timer piston in the injection pump (it is located in the lower part, where water usually accumulates) can also be the cause of a decrease in engine power, especially noticeable at high speeds.

A decrease in power at low speeds also causes clogging of the filter in the "OUT" bolt. This is due to a change in pressure in the injection pump housing, which also affects the injection advance. If there is a suspicion that the reduction in engine power is due to a bad turbine, then it should be checked. To do this, remove the rubber tube from the compensator on the injection pump and put a pressure gauge on it with a measurement limit of up to 1 kg / sq. cm. Now start the engine and spin it up to 4500 rpm. With a fully functional turbine, the pressure gauge will show at least 0.5 kg / sq. cm (the figure 4500 is taken from the Toyota Land Cruiser car repair manual, but has been repeatedly tested on other cars). Drivers do not usually notice a decrease in boost to 0.3 kg / sq. cm, although objectively the engine has become weaker. You can connect a pressure gauge in any other way, the main thing is to measure the pressure in the intake manifold, but using a standard compensator tube is easier. You can take a needle from a medical syringe, put a rubber tube on its back, which is connected to a pressure gauge. Now you can pierce the intake duct with a needle anywhere between the turbine and the manifold (where there is a rubber insert) and measure the pressure. Above, we were talking about diesel engines that do not have a throttle valve. If it is, the pressure should be measured up to the throttle valve. Most Japanese engines have a pressure of around 0.5 kg/sq. cm, although some models, especially gasoline ones, such as the Nissan Skyline, have a boost of 0.7 kg/sq. cm, and prepared sports even more than 1 kg/sq. cm. Reduced diesel engine power can also be caused by a bad air filter. As with all cars, including gasoline ones, the restriction of air intake immediately causes a restriction in engine power, which also smokes. I recall a case related to the lack of air in the 2L-T engine. The car came to us for repair after the cylinder head gasket was changed, and after the repair was completed, it lost power. It turned out that she just mixed up the vacuum tubes. In this engine, after the 88th year, they began to install throttle valve, which is controlled by a vacuum servomotor at the command of the control unit. All this was done for reasons of environmental safety, but due to improper connection of the pipes, the throttle valve did not open when the gas pedal was pressed. It just so happened that we didn’t have time to deal with the tubes, so we just forced the throttle open, and the engine got power.

3. Diesel engine shaking

If the engine shakes (this applies to all internal combustion engines in general), then some cylinders do not work or work poorly. When the cylinder is not working, i.e. the engine "troits", then the reasons for this are easily determined, since there are only two of them: no compression or no fuel. And it is not difficult to determine which of the reasons caused the defect. It is much more difficult to determine the cause if all the cylinders seem to be working, but the engine is shaking, and it is not clear what to do in this case. In a diesel engine, as already noted, the fuel is ignited by compression, or rather, by the increase in temperature caused by compression. Therefore, a large wear of the cylinder-piston group (and any wear is always uneven) leads to the fact that the compression in the cylinders is different. Consequently, the temperature in the combustion chamber at the end of the compression strokes will be different for different cylinders. When the engine warms up, the overall temperature rises, and although the temperature across the combustion chambers at the end of the compression strokes will still remain different, the injected fuel will begin to ignite confidently in each cylinder. The engine shaking will stop. An example is such a case. A "Toyota 2C" car with a well-running engine gets in for repairs because of a burnt gasket. Although a burnt gasket is usually the result of deviations in engine operation. After replacing the gasket and starting the engine, it was found to be shaking. The engine shook until the car had driven a few miles, after which the shaking stopped. The car was turned off, the engine cooled down, and after starting the picture repeated again. The reason for this behavior of the engine was that during the repair a new head gasket was installed, which was several "tens" thicker than the standard one. As a result, the compression in all cylinders decreased, and the temperature reached at the end of the compression strokes in some cylinders was insufficient for a sure ignition of the fuel. After a short run, the overall temperature of the engine rose, and the fuel began to flare confidently even in those cylinders in which, as a result of wear, the compression was underestimated. The second reason for shaking a cold engine is faulty glow plugs. Candles are known to serve two purposes. The first is to raise the temperature in the combustion chamber for easy starting of the engine and maintain it for 3-5 minutes until the engine warms up. The second is to improve fuel atomization. The jet of fuel from the injector hits the spark plug and mixes well with air, which contributes to good combustion. If the glow plugs are heated differently, then the temperature in the combustion chambers will be different, and the engine will shake. The same will happen if the spark plugs are not slightly warmed up after starting the engine, i.e. they will not be supplied with an undervoltage (5-7 volts) of the second stage of heating. All this will continue until the engine itself warms up. The voltage from the candles will then be completely removed, and it will not matter whether the candle works or not. But the candle still has one more function, and if its heated tip is burned, then the jet from the nozzle will not break into anything, the fuel in this cylinder will burn badly, which will also lead to engine shaking. Now about nozzles. If they have low injection pressure, then the fuel will not atomize well. If the fuel is badly atomized, then it will burn badly.

Even if the injection pressure of the injectors is normal, but they “dust” differently, then different amounts of fuel will enter different cylinders and it will also not be sprayed in the same way, i.e. this process in each cylinder will be different, which will lead to engine shaking. But raising the injection pressure of the injectors is also undesirable: the volume of fuel supplied will decrease. By ear, this can be determined by the hard, with detonation knocks, operation of a diesel engine, and it is harmful for him to work like that.

To avoid this, it is necessary, firstly, that the injection pressure does not exceed the value determined for this engine, and secondly, that the injection pump is correctly adjusted for a given injection pressure. You have probably heard stories more than once that someone replaced the nozzles, compressed the nozzles, made the injection pressure regular, and the engine began to work hard, with a knock. And all because either the high-pressure fuel pump is worn out, and its “health” is not enough to supply the required amount of fuel by pushing the nozzles, or it is incorrectly adjusted for a given injection pressure.

Let's talk about injection advance. It is clear to everyone that the longer the fuel is in the hot combustion chamber, the more likely it is to warm up well and burn out completely, even if it is poorly atomized. But too early injection leads to engine wear, to its hard work, although it slightly increases engine power and reduces smoke. However, diesel engine designers do this for environmental reasons, and as a result, many high-pressure fuel pumps have a warm-up device that maintains high idle speeds when the engine is cold and changes the injection advance somewhat, making it earlier. After the engine warms up, the engine speed decreases, the injection advance becomes standard for this engine at this speed, and the engine starts to run "softer".

When the diesel engine is revved up, for better mixture formation, and simply in order for the fuel to burn out, it is necessary to increase the injection advance. To do this, the injection pump has a special device. At the bottom of the pump is a spring-loaded piston, which is connected to a roller ring through a pin. With an increase in engine speed, the speed of the injection pump shaft also increases. On this shaft there is a feed pump, which, in accordance with an increase in speed, also increases the fuel pressure in the injection pump housing. The position of the piston and, accordingly, the turn of the entire roller ring, and ultimately the injection advance, depend on this pressure. If the fuel pressure in the high-pressure fuel pump housing does not correspond to the engine speed, a mismatch in the injection advance occurs. In general, incorrect injection timing may be due to wear in the injection pump drive (the belt, for example, has stretched out), wear in the injection pump itself (the roller ring constantly fidgets in the same place, which leads to wear and wedging), it can be caused by a downtrodden fuel filter in the "return", a faulty pressure reducing valve, etc. Injection advance may be abnormal in only one engine speed range or in all ranges, depending on which malfunction caused injection advance deviations. From experience it follows that only injection delay leads to noticeable shaking and even interruptions in the operation of the engine. Comes in for repair "Nissan Safari" with TD-42, "just off the boat." The engine idling works great ("it stands still"), you start to increase the speed - at first everything is fine, and suddenly after 2000 rpm the engine was changed. He's all twitching, shaking, it's scary to even look at it. At the same time, not one, but randomly either two or three cylinders are turned off.

In this mode of operation, of course, unburned diesel fuel flies out of the exhaust pipe, i.e. engine emits blue smoke. But after 2500 rpm everything is fine again, not a single flinch. Since the owner was pressed for time, we did not remove the high-pressure fuel pump and deal with its mechanisms, but, having unscrewed the "jammer", the "return" bolt and the fuel supply bolt, we simply blew the pump with compressed air (just in case), after which, loosening the fasteners, turned it to an earlier injection. All injection pumps on all engines are mounted in such a way that, by loosening the fastening bolts and nuts, they can be turned in one direction or another and thereby change the injection moment. This adjustment is the same as for gasoline engines when they rotate the distributor back and forth, changing the ignition timing. By turning back and forth the injection pump housing, you can change the fuel injection advance angle. But the distributor can be turned by hand, and the high-pressure fuel pump can only be turned by mounting, overpowering the rigidity of high-pressure metal pipes to the nozzles. After the adjustment, the engine immediately began to work normally throughout the entire rev range. It would have been possible to return the car, but in order to make life easier for the engine, we again gave the injection pump mount and turned it back a little. After that, in a cold state, at a speed of about 2000 rpm, he shuddered a little, but after a little warming up, this completely passed. It should be noted that all high-pressure fuel pumps are fastened in their front part to the engine front with two or three 12 nuts, and the rear part - with one or two bolts, usually 14, to the block bracket.