Now – an exotic error message of N43/N53 engine, so – a separate blog entry.

The problem is as if connected with the regulation of Lambda and cylinder No.5.

The attributes of the error message, although are not very clear:

a. fuel mixture data of the banks can no be seen, not taking into account, that DME as if has worked in Mode (Homogeneous mode; closed loop);

b. there are no specific data exactly about the 5th cylinder;

c. in the description is indicated that the fuel mixture was lean. But – was it really so? Maybe DME was forced to create a lean fuel mixture to compensate leaking of the injector (it is a typical defect of piezo injectors)?

Let’s see this case in more detail.

This error message refers to the error message group:

307C cylinder same adjustment via Lambda cylinder 1

307D cylinder same adjustment via Lambda cylinder 2

307E cylinder same adjustment via Lambda cylinder 3

307F cylinder same adjustment via Lambda cylinder 4

3080 cylinder same adjustment via Lambda cylinder 5

3081 cylinder same adjustment via Lambda cylinder 6

The error message group refers to mode: 

a. the engine works in Homogenous mode;

b. the engine runs NOT in idle.

Driving evenly in Homogenous mode, DME has detected incorrect performance of the appropriate cylinder. Faulty performance was seen during the test of chemical performance. More about the test of chemical performance you can read here.

Why is this error message exotic?

a. if the engine does not use Stratified charge, often these tests of chemical performance (also like these tests in Stratified charge mode) are paralyzed;

b. if the engine uses Stratified charge, tests of chemical efficiency more often are performed exactly in Stratified charge and typically precisely in this mode the injector problems are indicated primarily;

c. if any injector has started to drip/leak (typical defect of the Piezo injector), the most destructive impact of this defect is in idle. Accordingly, other appropriate error messages are typically recorded (ones referring to the tests of mechanical efficiency in idle) or – in idle misfires of some cylinder starts. 

This time happens, that evenly driving, exactly in Homogeneous mode the injector suddenly experienced unexpected problems. The car owner reported that the performance suddenly became very uneven; a powerful vibration could be felt.

At first – let’s check the compensation data of the injector dripping of cylinder No.5 in stratified charge mode:

Here, everything was fine with the injector of cylinder No.5 (last time, when the engine used Stratified charge in idle).

Data regarding injector flowrate correction in partial load mode, Stratified charge:

There has been no problem in this mode also.

And now – results of the last chemical tests of the injectors in Homogenous mode:

Here we see: for the injector of cylinder No.5, a powerful negative flowrate correction. So – indeed, the injector has started to leak strongly.

Let’s see in which segment this test has been performed. Let’s scroll the menu below:

We see that the last High range test results are correct, but Low range tests – have failed precisely in this (low range torque) range.

And this image we see, that:

DME has deleted learnbit of cylinder individual adaptations for Homogeneous mode and must perform quick injector chemical performance tests in Stratified charge mode. Quite logical DME reaction to the problem.

This time the situation is clear – suddenly, the injector of cylinder No.5 has started to leak. If the defect does not disappear after a short moment, the injector has to be replaced.

And finally: the lean fuel mixture, mentioned in the error message description, means – DME was forced to create a very lean fuel mixture, to compensate for the leaking of the injector.