As the pressure to reduce engine emissions increased, so did the way the fuel mixture was prepared. From indirect injection into the intake or pre-chamber, we have come to injecting atomized fuel directly into the cylinder. It also entails the need for higher injection pressures and very fine nozzleswhich spray essentially a “fuel mist”.
New fuel delivery systems also came, with the biggest revolution being about common-rail. The fine injection technique, where thousandths of a millimeter play a role, is logically very sensitive, although the injection takes place at a pressure of up to over 2000 bars.
Why does the injector fail?
Delicate electromechanics is very sensitive to any impurities. The injection must be extremely precise in order to spray the fuel dose correctly and evenly. Any inaccuracy will result in rougher engine running, higher consumption and over time can cause a very expensive breakdown, for example burning through the bottom of the piston.
One thing is impurities in the fuel – diesel engines typically suffer more from this. About fifteen years ago, the quality of diesel fuel was not at all famous in our country, but the current situation is much better. The problem is also bio component, which is no longer mandatory, but was until recently. Unfortunately, it was the methyl esters of acids from rapeseed or palm oil that caused the injectors to stick and malfunction. Anyone can do the same mischief mechanical impurity in diesel, if the car owner does not change the fuel filter regularly. Over time, if it is clogged, it will start to let dirt through and that is usually the end of the injectors.
This brings us to another factor that, unfortunately, the purest diesel cannot influence. If the car itself generates dirt, it is again a huge risk for the injector. This is, for example, small chips from the fuel pumpwhich he releases again old fuel filter. If it happens, for example, during a run of around 200,000 kilometers, the car owner will not be thrilled, but overhauling the injectors for ten thousand will solve it. It doesn’t take long and the fault repeats itself, unfortunately quite unnecessarily, because together with overhauling or replacing the injectors it is ideally necessary and clean the entire system of impuritiesor at least replace the fuel filter.
How do bad injectors show up?
If something is wrong with the injection, a specialized service will tell you more precisely, respectively injector diagnostics. But typical symptoms are:
- Rougher engine running – it causes incorrect dosing and dispersion of fuel. Over time, this can also cause higher thermal stress on the part of the piston and burn it out.
- Higher smokiness – poorer dosing of fuel also means poorer combustion and subsequent afterburning in the exhaust. Instead of the mentioned fog, the injection releases, for example, small drops into the cylinder, which do not have time to burn completely.
- Increased consumption – quite normally by half a liter to a liter per hundred kilometers.
- Bad cold starts – especially in the winter, faulty injectors can cause the car to start for a few seconds, sometimes it may not start at all.
- Engine emergency mode – this typically happens when full power is required and at higher revs. Clogged injectors cannot provide enough fuel to the unit, which the control unit throws out as an error and switches to emergency mode. Attention, the car will show similar behavior even in the event of a fault turbocharger control.
Info source: denso, dieselnet.
Media source: Depositphotos.
