Re-Installed my GMAF - what to look for?
02-07-2004, 03:47 PM
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Re-Installed my GMAF - what to look for? I had uninstalled my GMAF a couple of months ago because it was making the car run like ***.
Recently I re-installed it because I figured I could tune it a little for a rich/lean conditon with the MAF-T. Also, I was running rich with the MAF-T at 10% rich base, and when i changed it back to 5% rich, it would run too lean and the LTFTs wouldn't go to 0 like they should. I had heard that the GMAF leans it out a little so I was hoping that would bring it to the right mixture.
I went logging and everything looked perfectly normal at part-throttle, and at WOT it seemed to be a lot faster. We'll know on the dyno day however for sure.
I was logging the LTFTs, Fuel Trim Cell, all that good stuff. Anything else I should look for that will tell me this thing isn't doing its job?
I logged for a little bit and while driving my LTFTs were mostly at 0 and -0.8% and sometimes dipped to -3.x% and -4.x% at part-throttle. At idle they were way rich like -8% and -10%. That to me told me it was running better at part-throttle than sock and the same at idle.
Any ideas? I tried to be as thorough as possible.
UPDATE: Just got the average of the LTFTs from cells 0-19: -6.3x, -6.4x. Should I adjust the base for only 5% rich?
Recently I re-installed it because I figured I could tune it a little for a rich/lean conditon with the MAF-T. Also, I was running rich with the MAF-T at 10% rich base, and when i changed it back to 5% rich, it would run too lean and the LTFTs wouldn't go to 0 like they should. I had heard that the GMAF leans it out a little so I was hoping that would bring it to the right mixture.
I went logging and everything looked perfectly normal at part-throttle, and at WOT it seemed to be a lot faster. We'll know on the dyno day however for sure.
I was logging the LTFTs, Fuel Trim Cell, all that good stuff. Anything else I should look for that will tell me this thing isn't doing its job?
I logged for a little bit and while driving my LTFTs were mostly at 0 and -0.8% and sometimes dipped to -3.x% and -4.x% at part-throttle. At idle they were way rich like -8% and -10%. That to me told me it was running better at part-throttle than sock and the same at idle.
Any ideas? I tried to be as thorough as possible.
UPDATE: Just got the average of the LTFTs from cells 0-19: -6.3x, -6.4x. Should I adjust the base for only 5% rich?
Last edited by BigBlackZ28; 02-07-2004 at 08:41 PM.
02-12-2004, 01:45 PM
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I am doing some testing myself and when my car was running a bit rich the GMAF leaned it out for me but the numbers did not look as good. Odd thing was it felt stronger 
Stock MAF
GMAF
Stock MAF
GMAF
