MAF problem with supercharger

I posted this in here instead of the power adder forum because I believe it's more of a MAF issue than a SC issue.

I recently installed a Paxton SN92 on my 1990 5.0 5-speed, and I am having some trouble that I think is MAF related. The engine is stock with the exception of shorty headers, 24lb injectors, and a Pro Flow 75mm MAF (the chrome bullet one). The MAF is calibrated for a '93 cobra, which I believe just means 24lb injectors. I am using a Paxton red Fuel Control Unit.

When I go WOT and the rpm's hit around 3500, the car falls flat on its face. It completely loses power like someone yanked the coil wire off. When I back off the throttle, it starts going again. I originally thought the SC might be blowing out my spark, so I closed the gap to .025-.030 and it still does it. When I remove the supercharger belt, the car will pull to redline no problem.

I borrowed a C&L 73mm MAF (calibrated for 24lb's) from a friend and tried that. With the C&L the car pulls fine to 6000 rpm's, but I have a problem with low-rpm part-throttle pinging with the base timing set anywhere above 4 degrees. The pinging happens with the SC belt on or off. Has anyone ever had a similar pinging problem caused by a bad MAF? The pinging does not occour with the Pro Flow MAF.

My MAF is a drawthrough setup.

What could cause the Pro Flow to work fine naturally aspirated, but cut out with the SC belt on? I asume it has something to do with the increased airflow through the MAF. Is it possible that once the air flow gets to a certain level, the MAF gets confused and sends a bad signal to the computer?

Also, is it possible (although unlikely) that my computer has a problem?

Thanks a lot for any suggestions.

Jeff

vristang,

That's good to know about the cobra MAF not working with a 5.0 HO computer. I am using the stock HO computer.

The EGR system is intact. I actually just replaced the EGR Valve Position sensor because it had failed. It was pinging a lot worse at part throttle before I replaced the EVP sensor.

The fact that it still pings some with the C&L but not with the Pro Flow makes me wonder if there is something wrong with the C&L. I wonder if it is not calibrated properly, and it is making the computer run too lean and causing the pinging.

I would like to try another 24lb calibrated MAF, but I don't have access to another one.

Thanks for the info.

Jeff