What does my tuner mean when he says he's getting an erratic MAF signal? My MAF is in the fender and he had me put a piece of cardboard to block direct turbulent air coming from where my Fog light used to be....

He said it's going to cause drive ability issues.


Is he full of liberalism or is he on track?

 

means that the airflow into the MAF isn't consistent. If it's on the dyno, it should be. I'd clean your filter, use some brake-kleen (or contact cleaner) on your MAF, and see if it doesn't help. If you had to extend your harness to put your MAF into the fender, DEFINITELY check you wiring.

 

HAHAHAHAHA..... no.

 

What he says makes alot of sense. Most factory maf have screens before the maf sensor itself to smooth the air flow in a sense. I take it your maf sensor doesn't have a screen in it? heres a link of a stock maf with its screen. you may have to make one somehow to tackle your issue.
http://images.google.com/imgres?imgu...%3D1%26hl%3Den

 

Yes he is making sence. The air coming through the fog light is just like air from the fan hitting a ram air intake. It messes with the maf alot.

 

Could that have been the cause of some of my drive ability issues?

 

Absolutely. The actual sensor in the MAF samples the flow rate of about 2% of the air actually flowing through the MAF, and then "does the math" by assuming that the a proportionally similar amount of air is flowing through the rest of the MAF housing. Basically that 50 times more air than it sampled is flowing.

However if the flow through the MAF is turbulent the small sample may not be representative of the real flow, and more or less air will really be flowing.

The PCM doesn't know this and adjusts the injector pulse width to get the desired AFR with the amount of air it has been told is being sucked in. AFR will bounce all over, and load calculations (based in part on air flow and used by a number of other engine control functions) will also be affected.

The actual turbulence will be affected by vehicle speed (different speeds = different flow patterns in the wheel well), and the amount of air flow as the aerodynamics of the filter/MAF housing will behave differently at different air velocities.

PCM tries valiantly to do what it thinks is right and drivability suffers...

Oh, here's a "back-of-a-napkin" style analysis I did of the MAF, TBs. and the screen...

 

Thanks, that's the type of tech I was looking for... This site sometimes boggles my mind.