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Timing advance problem

573 Views 9 Replies 6 Participants Last post by  Joe Jagodzinski
I have an 84 gn with an 86 motor setup. I recently rebuilt my motor and am now experiancing problems. I have brand new cam, crank, knock, 02, sensors and module. After breaking in the cam and running the car for approximately 30 miles the car began to run poorly. It would begin to sputter, backfire through the exhaust and then die. The car runs fine cold and once it warms up it backfires and dies. All sensors have been checked and appear to be working fine. I have tried a new computer also. The car is currently at a shop and they cannot find the source of the problem. The mechanic says that the timing is advancing so far the car won't run. However he can't find out why. As I said all the sensors appear to functioning fine. Car runs the same in Limp home. The car only does it when hot, and runs great when cold. Any Ideas? I don;t know where to turn or what to try next. I am in Southern California. Who would you reccomend to work on it for me?

Any advice or help would be great.

Thanks in advance
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How long does it take to run poorly? As soon as it goes into closed loop, or after the engine gets good and warm?

If it takes awhile, and the timing is truly screwy, I would guess the module.

You might also verify that the damper bolt is still tight, and, try unplugging the cam sensor after starting the car to see if the problem goes away.

it takes about 15 to 20 minutes. once it is good and warm. tried unplugging the cam sensor and it ran even worse. put on a new module but the problem was exactly the same.
what's the condition of your battery and alternator?
both the alternator and the battery are brand new.
Cam sensor is 180º out or just out of whack.
If the cam sensor was out wouldn't it run bad even when cold? It runs perfect until it heats up, and then runs as S#$*Y as any car I have seen.
Also forgot to mention. I read a post on platinum plugs being no good for these cars. I have platinum plugs. Could this be the problem?
You should change plugs after breakin. They can get fouled. Platinum plugs suck under high boost but wouldn't cause your problem unless they are fouled too. You need to put a scantool on and post some readings.
I had exact same proble two years ago. Problem was a bad cam sensor. For what it is worth.
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