Fuel Trim Learn
01-09-2004, 11:36 PM
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Fuel Trim Learn I noticed that on my car, after doing a reflash, the car goes into Fuel Trim Learn mode (only using cells 20-22). I have verified with my scanner that it IS going into Closed Loop.
After I shut the car off and back on it returns the normal and hits all the FTCs.
The issue is that after it exits Fuel Trim Learn mode, the car runs like ***. It bucks BADLY when I first apply throttle, and TPS is around 10%. Usually, this is between 1600-1800rpm in all speeds and all gears (M6). This is the primary reason for me saying it runs like ***, because the bucking is horrendous.
The problem is absolutely 100% gone while it's in Fuel Trim Learn mode.
One other thing, may or may not be related, for cell 21 (decell) the LTFT values are [+25% -1.6%] Obviously bank 1 is pegged lean. Cell 22 (not wot) is [-1.6% -1.6%] perfect.
I have been trying to tackle this problem for several weeks and I'm about to drive the car off a cliff since the bucking is so bad.
PLEASE help me!
After I shut the car off and back on it returns the normal and hits all the FTCs.
The issue is that after it exits Fuel Trim Learn mode, the car runs like ***. It bucks BADLY when I first apply throttle, and TPS is around 10%. Usually, this is between 1600-1800rpm in all speeds and all gears (M6). This is the primary reason for me saying it runs like ***, because the bucking is horrendous.
The problem is absolutely 100% gone while it's in Fuel Trim Learn mode.
One other thing, may or may not be related, for cell 21 (decell) the LTFT values are [+25% -1.6%] Obviously bank 1 is pegged lean. Cell 22 (not wot) is [-1.6% -1.6%] perfect.
I have been trying to tackle this problem for several weeks and I'm about to drive the car off a cliff since the bucking is so bad.
PLEASE help me! 
01-12-2004, 01:55 AM
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Well nobody did help me but I was able to cure the surging problem. For some reason there was a huge spike in the IFR table (most values were 6 except for one cell which was 9) also the MAF table was not smooth (also had spikes), so I brought it into line more or less. That cured it. 
The car still goes into FTLearn mode sometimes, and I can't figure out what triggers it. It is throwing off my logs!
The car still goes into FTLearn mode sometimes, and I can't figure out what triggers it. It is throwing off my logs! 