Quote:
Originally Posted by 73TORANA!
Thx Steve for your reply, I think I may have poorly worded my question. there is no IAM drop and yes I understand you will get a richer mix with an IAM drop. My eng load is around .5 in cruise @ 2k rpm so I was trying to work out from the CL fuel correction table what the commanded AFR should be as apposed to the commanded AFR that im seeing on my OFT as it not what I thought it should be, forget actual AFR at this stage as im just trying to work out the how it is calculated from the tables I can see. I have read that the #2 O2 sensor in a UEL cattless header can cause the commanded AFR in C/L to drop / fluctuate and should have its table set to zero ??? thoughts. Cheers.
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Ok
OFT in general logs commanded afr about 0.2 afr points leaner than the correct value, jist a logging error i believe
Also in cruise mode the ecu also looks at the rear 02 senspr and apples a coreection to afr known as #AF3 correction, this is not reflected in commaned afr logged parameter.
You need to log #AF3 not sure if oft logs that
This can cause measured afr feom the front wideband 02 to drift from the commanded afr.
The rear 02 is only narrowband and only used for cat monitoring and cruise fueling correction.
Generally I zero out #af3 coreection in tune and many headers put the rear 02 in a long tube so fhe rear 02 sensor doesnt read correctly.