Routine repair of N53 series engine. I identified leaking injectors, and the mechanic replaced them. It was time to re-adapt the engine. The car was warmed up and driven for more than 10 minutes. Then I got to the procedure. First – the adaptation of the flywheel – no problem.
Then – fuel mixture. The engine was using Stratified charge; in this mode, data of the injectors (both idle and in partial load mode) were acceptable. In the Homogeneous mode, everything was different. Time by time, the engine switched to the Homogeneous mode, but no Offset, not Multiplicative type LTFT, were not confirmed.
I held the engine idle for a longer time, but Offset type LTFT were not confirmed. Bank Integrators – quite different from 0:
But without any progress. Also, the restarting of the engine and even putting DME to sleep did not give any result.
Here, ../F5/F6, fuel mixture menu, Multiplicative and Offset type LTFT marked with red – still not confirmed.
At the same time, live data of the injectors indicate (4th to 6th row):
Quite a significant Flowrate difference between banks is observed. Obviously, in the run, DME applies the Multiplicative type of LTFT of the banks but, for some reason, hasn’t confirmed them.
Learnbit of the injector adaptations indicated that DME has some kind of problems:
Normally:
a. DME colors 1. column, 3rd learnbit for a few minutes, performs quick chemical efficiency tests of the injectors; clear this learnbit (confirming the finishing of this test);
b. during several minutes, DME evaluates the complete fuel mixture of the banks (including the EGR system) and applies Offset type LTFT in such a way that Integrators should reach 0. As a confirmation, DME colors 4th learnbit.
Both tests take only around 5 minutes, but this time even for a much longer time – no progress.
Also, in the Homogeneous mode, the injector measurements are not performed!
What happened? There are no error messages in the DME error message memory!
Let’s see the primary data of the engine:
How so? The oil temperature was 93oC, but the engine temperature was significantly lower. It is close to 80oC, which corresponds to the Mapped mode. For some reason, DME tries to reduce the temperature?
The menu of the thermostat indicates that it is not warmed up.
Yes, there is no doubt that the thermostat is damaged and has stuck in the open position. So, the Mapped mode is not activated. Accordingly, till 95oC, the thermostat should be closed. The cooling radiator – should be cold. But when touching the cooling radiator, I concluded that it was hot. Actually, it was not a surprise because the temperature of the incoming cooling liquid (coming from the radiator) in the menu above: is 74oC.
I hope that with this example, I convinced skeptics that reaching the required temperature for these engines is critically essential. As we see, DME is not even confirming the bank adaptations. But that is only the beginning – DME does not perform a large part of the injector tests and does not confirm the results of performed tests/measurements. DME is a “vegetable”.
Here’s a note – such problems you can expect if the car has problems with:
a. thermostat, its heating system;
b. oil level, temperature and quality sensor, its communication;
c. cooling pump, error messages regarding its performance and communication with it;
d. error messages regarding the performance of cooling blinds;
e. cooling radiator (it has clogged) or cooling fan;
f. DME has had problems with ANY system mentioned above, and DME has not successfully performed (finished) the performance tests of the cooling system (it could last for several motor-hours, driving on the highway).
As a result of these problems, DME works in complete crash mode; as a result, you can expect the following issues:
a. increased fuel consumption;
b. vibrations, misfires, shivering – even disconnected cylinders;
c. overloaded un damaged CO catalytic converters;
d. damages of other elements of exhaust system: probes, sensors.
