I checked my notes and concluded that there are already 20 cases noted when unexpectedly ALL injectors started to leak and all had to be replaced. Now it’s the right moment to gather information and make conclusions. Yes, such cases are not often (20 of several thousands of engines with problems), but the consequences are dramatical enough to take time to describe these cases.
The statistics of these cases is the following:
- in 13 cases the owners of the vehicles admitted that before the accident have used the additive, which cleans fuel system/improves the performance of the engine;
- in 2 cases the owners “could not remember”, did they or did not use any additives. For me it sounds more than suspicious – amnesia is not a too common diagnosis;
- in 3 cases the car with the problem of uneven performance has visited a service, in which, possibly, some fuel additives were used to “solve” the problem of uneven performance. This time the amnesia had affected the specialists of the service center;
- in 2 cases the cars were used by other family members too, and no exact information was available (obviously, also these family members “did not remember” if they would use any fuel additives).
For me the most important in statistics of these cases – there is NOT ONE case when it would clearly be known that no, not any kind of fuel additives were used and the problem could be another.
Yes, theoretically it can happen that the fuel station has not cleaned its tanks properly and some chemicals have been left there. Exactly for this reason for the owners of the cars with N series engines, I recommend using only fuel stations of known brands. Do not fill fuel in small, half-abandoned fuel stations just because the fuel there is for several cents cheaper! In the tanks of such fuel stations, could be rust water, some dirt, leftovers of cleaning chemicals.
Technical note – simplified calculation. The injectors open for approximately 0.1mm. For the N43/N53 series engine, during 1ms (for the cold engine) it injects the fuel amount, necessary for idle (600 RPM). Accordingly – only 0.5um opening of the nozzle of the injector is necessary to double to fuel amount, which flows out the injector! For comparison – the diameter of the human hair is around 50 .. 150 (!) times larger.
Of course, there is no exact info, what exactly are the chemicals, which are so aggressive and do them harm. And there is also no information, what exactly these additives have dissolved.
There were several cases when the injectors leak very similarly – it allows us to assume that the chemicals have dissolved a tiny coating of some detail (and it has separated and has stuck in the injectors), for example – an oxide layer of the fuel line.
Leaking of the injectors is typically in the range from +200 .. +500% from the necessary amount (I take into account that approximately half of the leaked amount gets in the exhaust because it spills in “incorrect” strokes). Even the smallest leaking (previously mentioned: 200%) results in the inability of DME to reach the correct fuel mixture even by minimal Offset adaptations -1.00/-1.50 mg/stk (for N43/N53 series engines accordingly) and minimal values of the Integrators: -30%. Of course, that such dramatical leaking of the injectors damages the exhaust of the car immediately and permanently: Lambda probes, CO and NOx catalytic converters, NOx sensor. After stopping the engine, the leaked fuel floes in the crankcase, dilute the oil. As a result, the engine can suffer (N43 usually suffers) oiling problems.
What are the consequences of such cases?
Clearly – the injectors have to be replaced. In hard cases – LPFP and all low-pressure systems (LPFP itself, plastic pipes in the fuel tank, fuel filter, all valves) have to be replaced.
Preferably – complete cleaning of the fuel system (put out the old fuel, cleaning of the fuel tank and LPFP/HPFP), as a minimum – filling the full tank with clean fuel and “pouring out” of the “dirty” fuel from the fuel system, pouring out 1 .. 2 liters via injector outputs.
Repair expenses: starting from EUR 1200 (N43) and EUR 1800 (N53) accordingly.
Sentence of the entry: DO NOT use ANY KIND of fuel additives for the engines with piezo injectors (no fuel “improving”, not the engine “cleaning”)!