I have a 2001 WS6 that is "mostly" stock (lid, exhaust, throttlebody). Under full throttle, I have noticed that the engine starts to ping in the upper RPM's. I used to own a 1999 Trans Am and it would do this when I had it tuned with the hypertech III programmer. Anybody have suggestions?

 

are you using 93 octane?

 

Yes, and I also use STP treatment every now and then. The only gas I use is 93 octane from Texaco. I might have to switch to shell, but their highest grade is 91 octane.

 

i had that problem when i tried to make a smooth bellow and it didnt seat right. try another gas station maybe there gas sucks

 

Now that you mentioned it, I do have the SLP smooth bellow installed. I might try putting the accordion style bellow back on and see if that fixes the problem. I also de-screened my MAF, do you think that might have something to do with it?

 

Yes. Doing that screws up the a/f and usually means your running lean. Reinstall the screen if you can.

 

That sucks, I tore the screen up pretty bad when I removed it. I don't think that I could re-install it. Would getting it dyno tuned help my situation?

 

Most definitely! Your spark advance curve is possibly too agressive for the fuel you're running. I run mostly 91 octane here (even though I can get 94) and my timing is set to 22 degrees at WOT. I was getting too much pinging also when it was set higher. And I was losing 10rwhp because my computer then pulled out too much timing when it sensed the knock.

 

I don't buy that descreening your maf is going to make that much of a differnece. You should be able to fix any difference that it does make by just reseting the PCM.

Patman, you're getting detonation at anything above 22 deg on a stock motor? That seems pretty low to me. Maybe it's the 91, but I wouldn't have thought that would make much of a difference from 93.

 

Patman, why do you run 91 when you can get 94? So it is okay to run 91 octane on the LS1? If so, I'm going to switch from the 93 (texaco) and go to the 91 (shell) just to see what happens.

 

I'd say its the MAF. Open loop is solely MAF based over 4k rpms. The fuel added from having positive fuel trims usually isn't enough to compensate. Descreening the MAF definately skews the calibration, as well as just regular boltons.

 

Most detonation is from oil in the motor via the pcv valve! And running lean at WOT. Get a catch can it would defenitly help. And a good tune with preferably 93 octane.

 

I have been burning a little oil. You'll have to educate me. What is a "catch can"?

 

It goes inline on the pcv valve hose and catches the oil that would be otherwise sprayed in the throttle body on into the motor and cause detonation gumming ect.Check our sponsor AMW a little pricey but they have a specific bracket kit!

 

I just checked them out and shot them an e-mail. Thanks for showing me their site, I had no idea about catch cans. Do you think that I should also change my PCV valve?

 

That is never a bad idea.
I really think you should reset the PCM if you haven't already. This will reset your fuel trims, and should compensate for descreening the MAF.

 

How do I reset the PCM? (sorry, I'm kind of new to this).

 

Turn ignition on (not running, just in run), then pull PCM IGN & PCM BAT fuses. Wait about 5 minutes, turn ignition off, then replace the fuses. The car will probably hunt for idle for a minute. Considering the car is basically stock, you probably won't need to do an idle relearn, but if you search for it I'm sure you'll find some good information.
Anytime you make changes you should reset the pcm, it will probably take about 100 miles for the computer to "learn" what has been changed with the car.

 

Cool, thanks a lot. I'll do that today! Two more questions; what do you think caused this problem in the first place, a bad PCV valve? When I get the catch can and new PCV valve, what do I need to do to clean the oil spray that has already collected in my motor, will it just drive out or do I need to do something?

 

You can run some seafoam through the motor to clean it out.
As far as which caused it, who really knows, it could be either, or a combination.