E46Fanatics - View Single Post - CEL light on....SAP bad and other engine performance problems
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Old 01-26-2013, 09:52 PM   #36
OEM ///Member
Join Date: Nov 2009
Location: Fairfax, VA USA
Posts: 24,664
My Ride: 330CiC, M5, X5, E93
OK, maybe there is some confusion but the MAF readings are starting to sound more reasonable.

You have to have the engine under a constant load to get accurate MAF readings. You will see momentary jumps in neutral, but you need to have then engine under load to really see the max measurement from the MAF.

Around town you should get close to 30-40 Grams/Sec during the heaver throttle positions. This would typically be staying under 3k RPM.

I think my 330 was idling right about 4 Grams/Sec?

I will hold my comments on the MAF for the moment.

What would be helpful, do not even need graphs, is to gather the idle Fuel trims and post them. You should expect the long term fuel trims at idle to be under 3% on a decent running engine with few if any intake/crankcase air leaks. I prefer to see under 2% but at times this may not be cost efffective to look for issue between 2% and 3%.

Are your LTFT's still over 10%?

Also compare your STFT at idle and while cruising say 40-55 MPH, on a fairly flat road and maybe even with the cruise control on. The STFT will jump around a bit, it may be easier to graph a few minutes of these values, what I am looking for is how the STFT average is at idle vs cruise. STFT may be considered LTFT by many, but I am trying to understand how tight the intake and crankcase area at idle and what happens to the trims at cruise.
Solve your misfires, lean codes, rough idle - http://forum.e46fanatics.com/showthread.php?t=897616

Fuel pump failures - http://forum.e46fanatics.com/showthread.php?t=929501

Temp Info - http://forum.e46fanatics.com/showthread.php?t=964491

Hidden OBC Menu - Check Voltage, Temp, Fuel Level - http://forum.e46fanatics.com/showthread.php?t=239619

E46/E39 GM5 Door Lock Info - www.bmwgm5.com

Lower hose temp switch O-ring - BMW #13621743299
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