I have written many times – any modifications in the software of DME will only damage the engine management. I haven’t seen any positive result of “disconnection” of the NOx system, nor “upgrading” (disabling) of the Lambda probes, EGR or DPF (for the diesel engines) or other systems. Even “only” increasing of the torque in 99% of cases will lead to the engine working in emergency mode. Below I will describe a good example. It should be added that this time quite “advanced” specialists have performed – a lot of modifications have been done. How did it end? Read further!
An owned of N53 series engine turned to me with complaints regarding the very incorrect performance of the engine – shivering, misfires, reduced power.
The diagnostics discovered the first fundamental problem: instead of 5000 hPa the pressure of low-contour was indicated by INPA as only 600 .. 800 hPa
Logically – how the engine will be able to work properly? The error messages – also regarding low-pressure (static). For granted – this problem has to be solved first. Unfortunately, also after this repair (replacement of the LP pump), the performance of the engine was very incorrect – vibration, unevenness, misfires – full package of the problems. The next diagnostics session already indicated a correct low-pressure contour pressure, so – the previously described defect has been repaired successfully, but – obviously, it is not the only one. The most interesting part is only starting!
Checking other data of DME, I have to conclude, that the engine works in a complete emergency mode. Even the flywheel has no adaptations!
Mechanical efficiency of cylinders – incorrect! No LTFTare created, no bank or individual adaptations of cylinders are confirmed, etc. It is clear, that the engine has to be readapted before we can evaluate the true situation.
After readapting the engine.
Here, ../F5/F2/F6 menu, pay attention to the marked value. Normal HPFP pressure for the N53 series engine is 200.000 hPa (200 Bar). But here we see 50.000 hPa (50 Bar)! And – no error messages regarding inappropriate HPFP pressure!
It is possible, that someone (not being able to understand, why HPFP is not able to develop the required pressure) didn’t solve the problem with a low-pressure contour, but modified HPFP target pressure and/or deleted the error message map? Could be! I suggested to the customer to check the true HPFP pressure to understand, what happens with Rail.
Live data of the injectors indicate atypical opening time in idle:
Correct values in circumstances of 200 Bar: around 0.300 ms. This corresponds to reduced Rail pressure, but don’t correspond 50 Bar (or we have to assume – for some, unknown for now reason, first of the injection impulses is significantly longer – INPA don’t indicate it).
Here, the confirmed adaptations. As we see, the engine has not succeeded with cold engine Lambda adaptations for the banks, it has not tried to work in a Stratified charge. Even more: DME has not created even basic adaptations for Homogeneous mode! Where to hope for successful finishing of the individual cylinder adaptations. Yes, they are not finished too.
The tests of the chemical efficiency of the injectors are also not completed. DME has tried to perform initial tests of the injectors, applied identical corrections in all performance modes (both small and large required torque), but has not even confirmed these data!
Yes, the engine has not tried to work in Stratified charge for even one time – no adaptations in idle, or individual (injector) adaptations in medium load have been performed.
So, the leaking of the injectors is for small openings is not measured, their delay parameters are not measured. These are the most important measurements of the injectors!
At the same time – no error messages regarding NOx system (obviously, the NOx system has fundamental problems – only so we can explain the primal reluctance of the engine to run in Stratified charge during readaptation)? Interesting.
Here, the engine has not even performed the Lambda adaptations in other temperature segments:
Let’s see the menu of the NOx sensor. What’s that? DME doesn’t receive information regarding the exhaust temperature? No, as we see – the sensor is connected, ADC receives the data. But the displayed 0oC?
And what happened with the Lambda binary? In offline mode, the Lambda binary has to be 1200 mV, but here: 500 mV! Lambda linear: not 1.00,but 0? And no error messages regarding the exhaust temperature or the NOx sensor (which has not reached Online mode)?
Oh, and one more surprise here! The menu of EGR valve:
The potentiometer of the valve indicates, that the valve is in a half-open position, bit DME has fixed its impact of 0%! EGR: completely clogged? Mechanically damaged? Both adaptations (for small and large opening) – complete crash! And again – no error messages regarding the performance of the EGR?
Let’s check the fuel mixture data.
What’s that? Offset adaptations – not confirmed! Multiplicative type adaptations for the segment of the nominal temperature – not confirmed!
The actual multiplicative type adaptations – practically identical for both banks. There is no doubt: DME doesn’t create correct LTFT, it works in complete emergency mode!
Assessing the situation as a whole, it becomes clear: chip-tuning “specialists” have drastically “improved” this DME. The NOx system is “disconnected”, EGR is “disconnected”, HPFP settings are modified. The error message map is thoroughly interlaced. The result?
As you can see, pitiful.
DME tries to adapt (as if disconnected!) EGR, but without success, logically. The result: DME doesn’t switch to the full functionality mode even in Homogeneous mode, don’t create any LTFT.
DME doesn’t even try to work in a Stratified charge, don’t measures injectors (even in Homogeneous mode the injector tests are not successful!).
Unfortunately, such an engine will work worse than M50: even M50 creates LTFT. The situation is getting even worse with an obstacle -piezo injectors have a very wide dispersion of the parameters (unlike the “old” type injectors) and without their individual adaptations, the engine will not be able to work evenly. In several cylinders, the fuel mixture will be rich, in other -lean. Misfires, shivering, reduced power, vibration in a range of medium and high torque modes – it’s the everyday life of this engine. Even the average Lambda of the banks regularly will be outside the allowed corridor – there will be error messages regarding fuel mixture (unless they are not deleted from the Error message map), strong shivering, also the damping of the engine is possible.
One more nuance, which has to be taken into account – incorrectly working engine (without individual adaptations of cylinders) damages the CO catalytic converters. Unfortunately, while the engine has not reached a full functionality mode, it doesn’t perform the tests of the CO catalytic converters. The car owner will find out that these catalytic converters are damaged after a year or two when trying to pass TI.
