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Old 06-22-08, 12:46 PM   #322
landtank
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Join Date: Mar 2003
Location: Boston MA
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Quote:
Originally Posted by SS_Storm View Post
on a obd2 setup I normally look for a number around 0% fuel trim short and long term than I check the actual engine coolant temp
Given enough time STFT will always hover around 0% once the LTFT% has been achieved.

Adjusting the trucks so the LTFT% is 0 is a really bad idea. The two major influences on LTFT% is the altitude the vehicle is in and the air temp (density) at that time.

My truck has a LTFT% of +3 because I'm at sea level and others in higher elevation have LTFT% of -6%. This has been recorded on several trucks and I'm confident it can be relied on.

So targeting a specific value all the time with give you varied results. It would seem you need to read the LTFT% prior to the install and then calculate a %drop in it to achieve consistent results. And the only way to do this is to leave the MAF signal alone. It's the one single signal that you would need to ensure that the LTFT% that you end up with is valid.


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