Bless You, Diesel

GENERAL INFORMATION

The engine coughed once, then again, and went silent... Anyone who has been in this situation knows the swarm of questions that runs through your head during failed attempts to restart the "heart" of the "iron horse". Owners of diesel vehicles are no different from anyone else. However, the causes of diesel engine problems and the ways to fix them are largely specific to this type of engine. To avoid complicating things for yourself, it is best to follow the advice of professionals with solid practical experience in this field.

They were consulted this time as well, and gained a lot of useful information and fairly simple practical advice.

The biggest surprise is when an engine that caused no trouble yesterday suddenly refuses to "come to life" at the exact moment you are rushing to work in the morning. If this happens for the first time and is accompanied by white exhaust smoke, it is almost certain that the glow plugs are to blame. By the way, the indicator on the instrument panel may be wrong, showing that the glow plugs are "OK". To check, connect one end of a wire to the battery positive terminal and apply voltage directly to the glow plugs with the other end. If a good spark appears (it is easy to tell apart from a bright short-circuit flash), the wire begins to heat up, and the engine starts after that, then the glow plugs are not the cause. Look for the fault in the electrical circuits supplying voltage to them. The fuel supply valve can also be checked this way.

And finally, blame only yourself if you previously tried to start the car by push-starting or rolling start. The timing belt could easily have jumped several teeth. If the engine will not start, you may need to prepare for a complex and expensive engine repair.

Experience shows that another very common situation is when the engine runs at idle, but stalls or dies shortly after running when you try to increase engine speed. Most likely, air has entered the fuel system. Again, pay attention to the exhaust. In this case, it is usually white with a characteristic smell of diesel fuel. A vacuum in the fuel flow can occur due to a blockage, for example in the fuel pickup or the fuel filter. The fuel filter is most often the one that clogs, and such problems occur mostly in winter.

Specialists at Technodiesel advise everyone to follow a rule with no exceptions: never repair fuel filters. Various "flushing", "blowing out", and other supposedly restorative procedures at best have no effect, and at worst make the situation worse. Fuel passing through such a "restored" filter not only fails to receive proper cleaning, but also washes all the dirt accumulated in the filter downstream. This can quickly damage the precision mechanism of the injection pump.

Another pseudo-help for the engine that "knowledgeable" mechanics like to offer is installing several fuel filters. In terms of achieving unprecedented cleanliness of the diesel fuel entering the engine, there is no sense in this multi-stage filtration. Vehicle manufacturers carry out precise calculations of filter performance, which are confirmed by series of tests, so they should be trusted. Additional filters are not just useless but harmful. They create excessive resistance, so the injection pump works under overload and fails sooner. Increased resistance in the fuel line can also cause air to be drawn in.

Do not be misled by another fairly common misconception that additional filters help separate water from the fuel. In fact, filters do not retain water. For this purpose, there are special water separators (sedimenters). The presence of such a separator is indicated by a small plug at the bottom of the filter. Drain the accumulated water approximately every 3000 km. Keep draining until practically clean diesel fuel flows out.

Water in the fuel also causes white clouds of exhaust. Some modern diesel vehicles have an indicator on the instrument panel that reports water in the fuel. If the indicator lights up, stop immediately, switch off the engine, and drain the liquid from the separator. If necessary, repeat the procedure. If the indicator still does not go out, the problem is probably in the electrical circuit of the water-in-fuel indication system. Do not attempt to make quick repairs yourself; contact an automotive service center.

It also happens that an engine that was running smoothly suddenly stops for no apparent reason. The most trivial advice, which surprisingly helps in many "difficult" cases, is to make sure there is still fuel in the tank. If the problem is more serious and something has really happened, try to recall whether there was a sharp noise just before the engine stopped. A broken timing belt is accompanied by such a sound. If so, do not try to crank the engine, as the consequences can be destructive.

Another possible cause of sudden engine stalling is air in the fuel system. You can try connecting the fuel pump directly to any container of diesel fuel. If the engine starts running, the cause has been found. For any fuel pump problems, it is best to contact qualified specialists rather than entrusting repairs to questionable mechanics.

Once the injection pump has been ruled out as the likely cause of the problem, you can try loosening the fuel line fittings at the injectors. If diesel fuel leaks out in a pulsating stream from under the fittings while you are trying to start the engine, this means the faulty injectors are not supplying fuel normally to the combustion chambers. You may notice black exhaust smoke – this is one of the signs of a stuck injector needle. Fuel begins to enter the cylinder uncontrollably, and the black exhaust is caused by incomplete combustion of it. Warning: Also, do not drive recklessly through deep puddles. Workshops often see diesel engines damaged by such dunking. Water from the puddle enters the combustion chamber, and the powerful hydraulic shock bends even the strongest connecting rods!