Quote:
Originally Posted by Wagon_Si
thanks Scott, i will look at this over weekend, my original logs have the data you mentioned in them, i will digest when i have recovered from business trip this week.
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Bearing in mind that you think your over-fuelling have a look/log of the A/F Learning # 1, A, B, C, D as this is a long term fuel trim factor.
When you reset the ECU you will lose this information, so you need to do a few runs, primarily cruise and high speed cruise/part throttle for the ECU to calculate this trim.
This trim is worked out from the lambda feedback and is a +/-15% adjustment that the ECU can make to the fuelling in order to reach 14.7 AFR during idle/cruise.
However it applies this same +/-15% trim to the open loop/on-boost fuelling. It does not use lambda feedback during open-loop/on-boost so applies the trim it calculated previously to add the same level of adjustment to the MAF based fuelling.
Therefore if the MAF or injector scalings are not setup correct or you have fuel or air issue, this trim factor will creep up or down. The max allowed is +/-15%.
If you hit 15% you will get a CEL warning and error code. Normally a 'Bank Running lean' type error. You will also see this if you have an FPR or FPR vacuum/boost hose connection problem.
Ideally you want to keep it within 5%.
There are 4 (A, B, C, D) A/F learning parameters that feed into the A/F learning # 1 and A, B, C, D are all at different MAF g/s ranges. Looking at these will give you an indication where the fuelling needs to be adjusted.
Negative values indicate the ECU is pulling out fuel i.e you are running rich.
Positive values the ECU is adding fuel i.e you are running lean.
If their all more then 5% approx then injector scaling is a good place to start. If their all quite different then the MAF scaling needs looking at for the A, B, C or D range that has the issue.
If they are all quite different but all within 5% then don't worry, leave things as they are.