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View Full Version : 1985 GMC Jimmy 4x4 2.8 ltr - Timing problems


BluntMomma
08-25-2012, 10:41 PM
Hi

We have this gmc jimmy 2.8 ltr 4x4. It won't run unless the timing is 30 degrees or so advanced. If you put it into the proper position, it won't start. In the advanced position, it will...but runs pretty good, with a little bit of a rough idle. We have rebuilt the carb, replaced alot of the vacuum hoses, checked the timing chain and the valves...all checks out fine. The truck, over time, has gotten shittier and shittier until we couldn't start it. We found a wire in the distributor...from the ignition module to the coil that was damaged and had been saudered...it read intermittent on the om meter...we recut them and re-saudered them. That's when it started running better, but still...it runs at only 30 degrees off. Any ideas? It's not running smoothly and we want to take a trip this next week...need to get it on point! Please post your ideas.

85chevy
08-25-2012, 11:37 PM
Sounds like ur distributor is out which is y it runs at such a high advance. Or ur plug wires aren't in the right spot

Happypants
08-26-2012, 12:28 AM
Check your bolts for your intake manifold, 2.8's are notorious for the intake bolts coming loose but could be like terry said, check ur firing order

BluntMomma
08-26-2012, 09:54 AM
Thanks guys...have already done that. It's not the problem. I have also replaced the plugs, wires, cap and rotor, marked the wires before removing and replacing. There just doesn't seems to be any reason for it running only in an advanced position. Bluntdaddy is stumped. Keep the suggestions coming! :D

85chevy
08-26-2012, 12:54 PM
So when u fixed this wire u had the distributor removed from the engine?

Happypants
08-26-2012, 12:56 PM
Prolly got it out 180 degrees

85chevy
08-26-2012, 12:57 PM
no because it couldn't run that far out but if its a couple teeth out it would if u advanced it far enough

BluntMomma
08-26-2012, 02:04 PM
yes the distributor was out at the time. He's put it back in but as I said it won't start in the proper position. Once it's started, you can turn it back where its supposed to be and it will run, but once you turn it off it won't start again unless you advance the timing again.

abec
08-26-2012, 11:25 PM
Have you tried a timing light ?

Tinker
08-27-2012, 06:38 AM
Ummmm.......take it to a mechanic. Advice on the Internet is worth exactly what you paid for it! Nobody can diagnose a problem without being there and seeing for themselves. Or you keep going with the "maybe this" "maybe that" web mechanics.

Happypants
08-27-2012, 08:34 AM
Well Mabey ...:)

ray
08-27-2012, 09:17 AM
if i do believe so mabey lol this truck has vacume advance does it not. if this is case set timing in all factorg specs while U got it running once there unplug advqnce shut motor offf plug vacum line see if it fires up....

Happypants
08-27-2012, 09:18 AM
if i do believe so mabey lol this truck has vacume advance does it not. if this is case set timing in all factorg specs while U got it running once there unplug advqnce shut motor offf plug vacum line see if it fires up....

It might, just Mabey :D