Ok my friend just bought a 97 Z28 and this is what we do know. It has a cam, some headwork, headers, exhaust, and the PCM has been sent off to be tuned. Now the problem.........It is pinging at part acceleration and some at WOT. The knock sensor is stock and is showing retard of up to 10-14 degrees at part throttle(mostly at first gear hard launch). After 2nd gear comes in, the KR goes back to 0, power is restored and the car flies the rest of the way. The KR is showing 3-5 degrees at normal idle and 6-10 degrees at part throttle(minor part throttle). If you slam the throttle, it will ping noticebly. We then tried a LT4 knock module and it still pings. No scan passes on the LT4 module. So I'm thinking of desesitizing the knock sensor with a resistor to keep the KR at 0. My question is: would the engine ping with retarded timing? I thought it only pings with too advanced timing? When the KS is pulling, the car runs like crap and when it goes to 0, you can really feel it back to normal. Could the PCM be tuned to advanced? Or is the pinging from the KS? Any input would be appreciated.

 

Have you tried 100+ octane to see if its false knock?

 

nope.......Im figuring its false because it has knock retard at idle and it worsens at the slightest throttle. the knock retard goes away after the car gets going (2nd gear and up). I was thinking maybe the engine was runnin too lean, but the car pulls faster the longer you hold the throttle???

 

Ahhh, if it is pinging it isn't false knock buddy, you should pull some timing out because it is probably too much for that set up, try runing some race gas through it and see if it goes away. if it does pull the timing out some. You best bet is to have it dyno tuned.

 

why would a tuner advance timing that bad in the first place? and what octane is best to try? I can get a hold of some leaded 106, 110, 112, and or 116?

 

Don't put leaded in there...

 

will that kill the 02s?

 

is there anyway I can pull timing without having to send the pcm in the mail or dyno tuned? any simple tricks or is there any tuning program I can buy so I can do it myself? links would be useful.

 

Get a cable from www.AKMCables.com and there is LT1edit, tunercat, etc.. plenty of software available.

 

thanx bro