I have a 94 T/A, and recently noticed that it wasnt pulling as hard as other cars of the same year(biggest time i noticed was at the track when i ran .6 slower than car with identical setup). I put my scanner on the car and come to find out that its retarding timing when ever i go WOT. Ive got a fiarly new opti(maybe 6 months) new coil, knock sensor tested out ok and a new lt4 knock module. Im not sure whats causing the problem and was wondering if anyone out there has experienced this problem.

 

What grade fuel are you running? What does the coolant temp look like when you are seeing knock retard? Are there any internal mods to the engine that would affect compression ratio? Are you running a stock tune? Do you see knock retard at any time other than WOT?

 

93 octane, temp is between 170-185, engine is stock,only using hypertech tuner, doesnt matter if its installd or not. Occasionally see timing retarded from take off at stop signs or lights.

 

Did you have the problem both before and after the LT4 KM?

 

Before I changed my exhaust setup I would get knock at various times like wot & deceleration. I think my exhaust was rattling or tapping on something causing this. I have gotten none on several datalogs since it was changed. It could have also been from an exhaust leak but never found one that would have caused it. I also checked the valves and someone had most of them over 2 full turns past zero lash. Do you hear anything coming from under the valve covers thats sounds unusual? The knock retard unless its false knock is telling you something is wrong internally.

 

yes, problem has been there before and after. Im going to replace the knock sensor tomorrow just to see if that changes anything, it tested out ok but its possible it isnt working correctly.

 

Make sure the knock sensor is for an OBDI car, not the OBDII version.

 

Are you running premium fuel? No "shortages" there in FL?

 

lol, no no shortages in florida on premium, im happy its finally back to sub 3.50 per gallon. Under neath the valve covers sounds fine, no unusal noises, i know what an un adjusted valve can do.

 

Did the problem show up before or after you replaced the Opti?

 

Good question.....


Try to verify the timing with a light, the opti could be out of sync with what the original one was.


Is it pulling it all the time or just WOT?