This seems too simple but I need second opinions. I just replaced my timing chain and now I have a rough idle. I set the timing but that didn't help. It almost feels like a missing cylinder. In the past I could jumper the A and B terminals on the computer plug (technical term) and the idle would drop a bit. Now it does nothing. I do get a little advance when the enging is reved but only about 3 degrees. I don't think it matters in this case but I've never been able to get in to "field service" mode before either. Reading codes is no problem. Any ideas??

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85T/A 305/QJ work in progress.

 

Check for vacuum leaks or maybe a burnt/fouled plug wire.

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I can die now knowing I have fulfilled a dream. 6th row from courtside.
'86 IROC
T-TOPS, TINTED WINDOWS, BRAKE LIGHT BLACKOUTS
GM GOODWRENCH 350
EDELBROCK TES HEADERS
3" Hooker CatBack w/Aero Chamber muffler
EDELBROCK 600CFM CARB.
KN AIRFILTER
ACCEL HEI DISTRIBUTOR
160* Stat, just switched to 180* b/c of winter coming and going to college in the mts.
3:73 Posi
Rebuilt 700R4
B&M Megashifter, 5" Autometer Tach w/shift lite

 

hopefully you didn't put the chain in one tooth off.

 

It shouldn't be one tooth off since the timing is right on. I thought I might have at first since I accidentally moved the crank a touch when I was pulling the sproket off.

 

ignition timing and cam/crank timing are two different things. having the cam one tooth off means the valves are opening and closing at the wrong time. ignition timing is when the spark gets to the cylinder.

 

Ahhhh, I didn't know that. I sure hope I didn't do that. It's running good enough to get by for now so I won't tear back in to it to check.

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85T/A 305/QJ work in progress.