Why do I have boost?

Black Stampede said:

How did you car go from running great track #s to running like garbage?

Click to expand...

Simple....I removed the tuned SCT chip and installed an AEM that I'm tuning myself.


Could a backfire into the intake cause this? It was missing and running rough, so that's the only thing I can think of. Unless there's a problem with the MAP sensor or it's not set up right in the AEM.

I sync'd the timing tonight, and it was off by a degree or two. I had the dizzy set at 10* with the stock computer, so I never thought to sync it with the AEM since it defaults to 10*. I also tried to adjust the O2, I connected my voltmeter to it while the car was running and matched the AEM as close to it as I could get. I think it was off by a good bit if I got it set right.

The car now runs up to 5500 at least, which is the highest I took it. It's making decent power, but nowhere near the 450rwhp it was making before....I'm low on cash, so instead of buying a new air filter I just stuck on an old k&n filter I had laying around for now. That could be part of my problem.

http://www.mustangaddiction.com/aem/datalog3.jpg
There's my latest data log with a WOT run from 2000 to 5500 rpm in 2nd gear. It seems like it builds pressure up to 3900 rpm, then it drops off instantly from 1.1 PSI to -1.6 PSI. There's not much of a change at that rpm in the fuel and spark tables...