Performing adaptations is very important stage after replacing any meaning component of engine.
What does it means – to perform adaptations?
To perform adaptations: to create an initial maps for all management systems (long-term fuel trim map, ignition map, etc.) and coefficients (multipliers for cold engine fuel corrections, etc.). Long-term fuel trim coefficients and maps describe differences between perfect function of several technical solutions (for example, equipment unit & sensors) and current performance in real time (parameters and curves) – observing unit’s and/or sensor’s performance, engine “learns” and makes corrections in its performance. For modern engines, adaptations are created for: accelerator pedal, throttle, VANOS, crankshaft, camshaft and knock sensors, fuel and ignition supply, wide-band Lambda probes, NOx sensor, etc. During all engine’s lifetime fuel trims are corrected and renewed, according to real situation (fuel, its quality, component wear and change of parameters, etc.).
Adaptations has to be renewed, if any of mentioned components is been replaced: sensor, ignition coils (after misfire), injectors, not to mention more serious details (VANOS, pistons, etc.).
This time more detailed about long-term fuel trims.
The old fuel trims can be deleted both in INPA and ISTA D.
Deleting fuel trims via INPA (the sample is valid to N43/N53 engines, but the same principle has to be performed to other engines)
INPA MSD80 loader 1.01 :
a) in INPA choose engine: MSD80 for N43/N53;
b) choose deleting option for fuel trims: press F8;
c) choose the 2nd group: press F2;
d) press F6, to delete long-term fuel trims.
Note: the engine has to be switched off, ignition = ON.
INPA MSD80 loader 2.023:
a) in INPA choose engine: MSD80 for N43/N53;
b) choose deleting option for fuel trims: press F8;
c) choose the 2nd group: press F2;
d) press Shift + F9, to delete long-term fuel trims.
Note: the engine has to be switched off, ignition = ON.
Note: For N43/N53 series engines: if OEM NOx sensor installed, please perform Forced desulphation session BEFORE clearing of adaptations, as described here.
Confirmation of successful clearing of adaptations:
INPA loader 2.023 ../F5/Shift + F6/F2. All learnbits should be UNCOLORED (white).
INPA ../F5/F6. All LTFT (offset and multiplicative type) should be 0,00.
Deleting fuel trims via ISTA D: in case the engine has recorder error messages regarding uneven running (in Homogeneous and/or Stratified charge injection modes), or, if the replacement of injector(s) is confirmed, ISTA D creates sub-part of service plan: deleting the fuel trims. In this case you just have to follow the instructions.
Or: select Vehicle management/Service function/Power train/Engine electronics/Adjutment functions/Delete adaptations (variants).
Note: by deleting adaptations, the synchronization of cylinders (long-term trim for crankshaft sensor/flywheel long-term trims) are also deleted, so the first session of driving will be with unheated Lambda probes (see description below).
Example: clearing of adaptations using Vehicle management/Service function:
I recommend to delete fuel trims to warn engine – then it’s possible to evaluate settings for new long-term fuel trims. After deleting long-term fuel trims, you have to plan both time (about half an hour) and place (calm stretch of road) to create new long-term fuel trims.
After deleting long-term fuel trims:
1. First driving session will be with switched off (unheated) Lambda probes – the flywheel data long-term trim will be in progress. To perform the flywheel long-term trim, speed up in 4-th gear to 4000 RPM, and, lay off the accelerator pedal (use the manual mode, if your car has automatic transmission), slow down to 2000 RPM. More about flywheel adaptations: see entry about flywheel adaptations. Let the engine run idle for 3 .. 5 minutes. The performance of engine can be quite dull. After this session: turn off the engine and also ignition, wait, till MSD80 “goes to sleep”, it means, the lighting of Start/Stop button is switched off. Then I start the engine, go to point 2. If long-term fuel trims are deleted via ISTA D procedure (change of injectors, Rough run test sequence) – this part is not necessary;
Rough run menu: ../F5/F7; Status of flywheel adaptation marked with red
2. Start the engine, allow it to idle run for 5 .. 10 minutes. At the same time would be very good to control short-term fuel trims and values of offset long-term fuel trims. When offset long-term fuel trims are overwritten, (short-term fuel trims are within their normal range), speed up (easy, without too much enthusiasm, not to catch misfire) to 70 .. 90 km/h, switch the Cruise control on and drive for 10 .. 15 minutes. If MSD80 don’t has any error messages, the engine is supposed to perform in Stratified charge mode. First 3 .. 5 minutes Lambda values can fluctuate quite significantly (because the engine control unit perform long-term trim to injectors, increasing fuel supply one by one of them). After 5 .. 10 minutes Lambda values is supposed to become stable, between 2.6 .. 3.2; when it’s stabilized, switch off the engine and ignition, wait, till MSD80 “goes to sleep”, then move to point 3;
Fuel mixture menu: ../F5/F6; STFT (integrators) and offset type (idle) LTFT marked with red.
Fuel mixture menu: ../F5/F6; multiplicative type (partial/full load) LTFT marked with red.
Fuel mixture menu: ../F5/F6; Lambda values marked with red.
3. Turn on the engine, allow it to run idle for 5 .. 10 minutes again. In this point repeated modification of long-term trim for idle run will happen (long-term trims has been changed, because MSD80 re-adapted the injectors according to their real flow characteristics). When offset long-term trims are overwritten, it can be considered, that initial long-term fuel trims (for both banks) are completed.
Of course, the engine will continue with creating long-term trim maps for other performance modes (high load, cold engine etc.) and perform efficiency tests for each injector, but you can at least evaluate the success of both long-term fuel trims and also drive normally. While performing long-term trims, the engine can “catch” different error messages: about fuel mixture discrepancy, about CO catalytic converter insufficient performance, unevenness of engine operation. Some of the error messages stops creating of long-term trims, so it is very important to spot these error messages immediately, delete them and repeat the actual long-term trim stage.
Injector’s learnbit menu: ../F5/Shift + F6/F2. Status: all cylinder’s individual adaptations are completed.
Correct values:
../F5/F6
a) multiplicative type adaptations should be within -20 .. +20 % range and different from 0.00;
b) offset type adaptations should be within -1.0 .. +1.0 mg/stk range and different from 0.00;
c) each type of adaptations (offset and multiplicative) are NOT similar for both banks.
../F5/F7
Rough run values are fluctuating around 0.000 (that means – change their ‘polarity’ regularly)
../F5/Shift + F6/F1
Lines 4 .. 6: values within allowed limits
../F5/Shift + F6/F3
all values within -5.0 .. +5.0 % range
../F5/Shift + F6/F5
First 6 lines: all values within -1.0 .. +1.0 mg/stk range.
Yes, usually nobody strains to do this – error messages deleted, problem solved, happy travels. Unfortunately quite often it ends with uneven running of engine, lots of error messages and again – to service, look for a problem etc.
Short step by step procedure is described here and here
Official version from BMW regarding long-term trims (for ‘usual’ petrol engine):
a) Car must be at operating temperature/warm;
b) Drive vehicle 50 .. 60 mph with 2000 .. 2500 RPM for at least 3 min* (use manual shift, if needed);
c) Perform at least 2 .. 3 drive cycles if possible;
d) Let vehicle idle for about 5 min;
e) Recheck mixture adaptation values.
Note: for N43/N53 series engine we recommend to increase length of driving sessions up to 15 minutes and include flywheel adaptation session.
Note 1: when adaptations are cleared, following error messages* can appear immediately:
- error messages relating DSC. Solution: drive 10 .. 15 min, turn off/on ignition;
- error messages relating throttle. Solution: turn ON ignition (engine = OFF), press and release accelerator pedal for 3 times, then start engine.
Note 2: during adaptation process (after old adaptations have been cleared) some error messages* can appear:
- error messages relating fuel trim (bank and/or cylinders individually);
- insufficient performance of CO catalytic converters;
- Lambda probes (trim and/or signal);
- uneven run (Stratified charge and/or Homogeneous injection).
*these error messages in the exact situation do not indicate any problems with the engine performance.
After new adaptations are completed (after 5 .. 8 driving sessions, at least 200 .. 300 km), check the new adaptations and clear error message memory using INPA or ISTA D, if necessary.
Related entries:
Procedure: how to create flywheel and initial fuel adaptations using INPA
