minytrker

iTrader: (13)

Im am looking at a guys gto tomorrow that installed a aftermarket maf and has a preditor handheld. I guess he has messed with so much stuff with the hand held that he is getting a check engine light for being rich sometimes. I plan on having him flash it to stock and then I am going to data log his car and try to see whats going on. All he has is the maf and bolt on mufflers, is that enough to make it rich? Do you have to adjust the maf table for the aftermarket one, he said the paper work never said anything about it.

horist

aftermarket mafs are the devil.... they can cause lots of differences in AFR....

Stock MAF is best... when that is exceeded then it's time for speed density ...

Aftermarket MAFs work by reporting different flow numbers.... they do this in an attempt to change the OEM AFR (richen or lean the car) .... if he can ditch the aftermarket MAF he'll be better off...

minytrker

iTrader: (13)

Im sure that not the anwser the owner will want to hear, lol. I don't have his stock tune to look at but I down loaded a stock gto tune and compared it to what he has done with the handheld. His fuel and timing have been changed which he told me did, but they are far from being smooth. I was hoping to be able to help him out with the maf. He is going to flash his car back to stock and sell his handheld and I am just going to do a little tweaking till we can get it on the dyno or a wideband installed. I have a script that I use on pretty much all corvettes, it should work fine on the gto, right.

TimZ28

Aftermarket MAFs are absolutely no problem if you take the time to recalibrate the curve. The same applies even when using a stock MAF. I calibrated my stock MAF curve last weekend. On the 05 GTO the higher frequency range (WOT area) over-reports the true amount of air flowing. Ever wonder why your true A/F ratio never matches what the PE is calling for? Once you get the MAF calibrated true A/F will match PE.

minytrker

iTrader: (13)

How do you go about calibrating it?