Sxynerd

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?

Lito

He is on track, these cars MAFs are pretty sensitive specially with a nice flowing filter.

Texotic

yeah, our MAF is just uber sensitive...

Sxynerd

So should I make a wind break in my Fender?

kcmarti

Not necessarily a break. There have been more than a few articles on this in some of the Mustang magazines, what you need are “screens” that straighten out the air flow for your MAF. I saw some a few months back, but forgot the web site. Maybe search on MM&FF or Google.

Here is an extract from MM&FF (http://www.musclemustangfastfords.co...nlet_tube.html) on this issue:

We encountered one little glitch during this story, though. Every once in awhile, there's a vehicle that doesn't like the MAF sensor placement, and the computer gets a funny reading. Turbonetics and Mike Dezotell of Dez Racing don't know why, but the quick fix (as per Turbonetics' instructions) was to add a screen that the company sent over to us. The screen straightens the airflow in order for the MAF sensor to get a clean reading. It was a simple screen available at any hardware store. As simple as it was, the thing worked, and the troubles cleared up. The problem we encountered was a rough idle, horrible driveability, and overall poor performance due to the bad MAF sensor reading. At first, we were troubleshooting the problem, thinking the source was the tune, which wasn't the case. Then we thought the wrong pipe was installed, so we e-mailed a photo of the inlet pipe to Turbonetics, but it turned out OK. The straightened air remedied the problem, and we were out having fun with the '07 Stang in no time.

Norm Peterson

Cliff's Notes version - MAF's work based on how effectively the airstream is able to cool a heated wire down (determined I think by how much current is required to keep the wire at a constant temperature). Turbulent air can vary the cooling effect either randomly at a steady engine rpm, not consistent with respect to whether engine rpm is rising or falling, or (briefly) faster than could possibly be consistent with any normal change in rpm.

Fuel requirements (injector pulse widths) are based on how much air the PCM thinks the engine is using, so a spastic MAF signal is going to make the actual A/F ratio jump all over the map (the driveability thing). Or else the PCM decides that the MAF signal is so far out of agreement with other sensor information that "this MAF information can't possibly be any good", throws an MAF code, and possibly defaults to a "limp-home" mode.

This might be due to MAF/system uber-sensitivity, the physical placement of the MAF, the aerodynamics in the vicinity of the air intake, or some combination. Cleaning up the intake airflow is the solution, as this is a good thing all by itself.


Norm

Nuke

Great clarification, Norm. Thank you.