Timing Issue

[One Bad Chevy]

My 93 chevy has the 350 with a mild cam. It won't run right at tdc. Ive been told to set it at 6 BTDC, it runs better but no power at high rpm. I put a timing light on it and watched the automatic advance as i revved it, and noticed that it actually retards the engine as it revs up. Anyone know a possible reason/solution for this problem.

[b8k2jha]

What does it retard it to?? What type of ignition sytem?

[Jimmiee]

Does it have a vacuum line? If so disconnect it and you won't see it retard the timing as you rev it up. What happens is the full manifold vacuum has it advanced at idle. When you rei it up the vacuum drops to zero and the timing retards.

[One Bad Chevy]

I have it set at 8 BTDC with ignition bypass disconnected. When the wire is connected it looks like the timing jumps to 20 or 25 BTDC, and when revved it moves closer to TDC. It is all electronically controlled.

[ct9a]

Is the engine knocking? Are there any vacuum leaks? What do the plugs look like? Just some thoughts.

[bry2500]

If you have any knock at all the knock sensor will retard your timing. Even a noisy lifter could trigger it. 2 things to try. Try high octane gas 93+ octane and/or unplug the knock sensor and see if it relieves the problem.