Please help!! Car won't run right...

[Blown86GT]

I have a 408 with an S-Trim supercharger. It is controlled by a bank to bank FAST system with a wide band 02 sensor. This setup gave me a very strong running Mustang with 617rwhp.

I recently noticed the oil pressure dropping as I would drive and decided to tear down the motor. I found a cam which was flat on several lobes so I replaced it with the exact same cam and reasseymbled the motor.

Now car revs slowly and the power output has dropped drastically. It will backfire thru the exhaust during normal driving. I am using the same program as I had before.

To me it sounds like a timing problem. Anyone have any ideas?

Paul

 

[TwinTurboIroc]

Well unfortunately you are going to have to re-tune the motor. Think about it.....you had the fuel/timing setup for a motor with a cam with wore lobes

now you have a fresh cam......you are gonna have to change things

 

[Craig Smith]

Do you know for a fact that the cam is the exact same as the previous one? Were the cams degreed in the same? A little difference in cam timing can make a pretty significant difference in how it runs.

If it ran great, then the cam wiped out, you changed it, and now it runs poorly, it only makes sense that the cam and/or the installation should be the prime suspect. I've done this myself and have seen many people go through it as well.

Also, are you sure nothing else was damaged when the cam went out? All that metal had to go somewhere, and you didn't mention a rebuild. My engine dropped 120 horsepower when a rod bearing went out.

 

[Blown86GT]

I rebuilt the motor, had the same problem then had the motor professionally rebuilt. (Keith Craft Racing) I know the motor is mechanically sound. I even leak down checked it...4 % in all the cylinders. The cam was checked and it is the right cam. It was degreed exactly as the original cam was.

My program is based on a blown 331 with 20lbs of boost. I did change the basic setup for my car such as injector size, firing order and cubic inch parameters but thats basically it. It had run just fine with this program before. I guess I'm saying the program never was tailored to this motor per se.

Is there a way to identify a problem with the FAST system? The car has only been started a couple of times in the past year. Could inactivitey cause problems with FAST? Or could my file some how be corrupt?

Paul