i set my base timing somewhere between 6-8 a few months back with the install of my new distributor. ive been having a problem lately with the car breaking up so i decided to check the timing today and with the wire unlpugged it was at 20 degrees but very jumpy probal by abou 6 degrees and with the wire connected at 40 degrees. what could cause the timing to be that far advanced and why so jumpy i remeber when i set it it was very smooth and consistent at idle.

 

What distributor are you using?

 

msd but when i first installed it the timing was steady. now its jumping all over the place running like complete sh*t. if i rev the car out it breaks up soo bad through out the next gear i have to let off the gas till the car smooths out

 

any suggestions guys

 

Sounds like it's changing by about the right amount when you plug the wire back in. That's what it's supposeed to do: you set the "base" timing with the computer disabled, then when in "normal" mode, the computer takes over and puts it in the right place.

The static ignition timing, i.e. where the dist is in relation to the internals of the engine, doesn't just up and change all by itself out of the clear blue. Not sure why people always think they have to dink with it, but then what do I know. But, if it ran right set to one place at some time in the past, then it's not the problem; put it back there, lock it down, and leave it alone, and find whatever is REALLY wrong with the engine.

I'd suspect a vacuum leak or a fuel pressure issue. Busted rubber hose, something just disconneced, needs a new fuel filter, stuff like that; in a word, something that CAN change all on its own, unlike the ignition timing.