On my 383, 219, TF car with a VERY mild tune. My timing has to be -4 degrees timing to avoid chatter. Any suggs?

 

Maybe your harmonic balancer has slipped and the base timing reading is inaccurate. You can check it with a piston stop, or you can pull the balancer and check the timing mark/keyway alignment.

Otherwise, bad detonation can be caused by excessive carbon in the chamber, low-grade fuel, clogged injectors or fuel filter (causing a lean mixture,) and various other things.

 

My /87 TPI acts the same way, And I did the same thing you did to get it to stop.

But, I do not have a VSS (Vehicle Speed Sensor), so I believe my computer thinks my motor is in neutral, so it will not retard the timing. (Possibly a problem with your VSS)

Apparently if I have my computer programmed to think the car is moving over 4 MPH than the computer-controlled time should work.

 

Your timing will not effect valve train noise. I think you are confusing two seperate things here.

 

It will affect it if it's not actually caused by the valvetrain. What most people call "valve rattle" is actually detonation, which is often caused by over-advanced timing.

Oshdog...you can't program the computer to think it's always moving. The MPH reading is stored in RAM which is reset every time you turn the key on. I suppose you could change the actual software code in the ECM, so that it doesn't look for the VSS at all, but you'd have to know the code fairly well and then there's still the chance of causing problems in other parts of the code. It would probably be better to just put in a VSS.

 

Solved. Faulty Prom.