302 backfire unless 25 degree retard - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

dmc919 · 08-20-2006, 06:35

If I set the timing at 6 advanced and have the vacuum advance on then at 1k rpm it starts to backfire, so i take the vac advance off and it's alittle better then i start to retard it and i can get 5500 if i retard it 25 degrees, what the hell is the problem. The motor was fuel injection and I put an edelbrook intake, holly 670 carb, vac dizzy, msd ignition/coil and replaced all the gaskets and timing chain, also the heads had a valve job and shaved slightly to make sure there flat.

GHarper · 08-28-2006, 16:30

Quote:

Originally Posted by dmc919

If I set the timing at 6 advanced and have the vacuum advance on then at 1k rpm it starts to backfire, so i take the vac advance off and it's alittle better then i start to retard it and i can get 5500 if i retard it 25 degrees, what the hell is the problem. The motor was fuel injection and I put an edelbrook intake, holly 670 carb, vac dizzy, msd ignition/coil and replaced all the gaskets and timing chain, also the heads had a valve job and shaved slightly to make sure there flat.

Is the computer still controlling the the spark or have you wired the module directly to the coil as the computer controls the ignition timing based on the antiknock sensor which is no longer connected.

If you have wired the coil direct to the module, check that the module is correct unless it came with the distributor.

Hope this helps.

Greg.