Barely idles
Thread Starter
7th Gear
Joined: Sep 2017
Posts: 7
Likes: 0
From: Coarsegold Ca
Barely idles
96 LT1 collectors edition. I replaced front engine seals, rebuilt opti spark, water pump,plugs, wires. Car barely idles now with no acceleration. Tried new temp sensor with pig tail no difference. Re checked wires firing order all good. I do not have alternater hooked up do to 3wire plug damaged. New one on way. Any ideas greatly appreciated. Car ran perfectly fine before this. Thanks
Team Owner
Joined: Jul 2004
Posts: 28,416
Likes: 3,271
From: Hartford WI
What exactly does that mean?
Have you tried scanning it and seeing what the ECM sees for IAC counts? Assuming you are right on the spark plug wires.
Have you checked fuel pressure? Spark quality? All injector wires good? Give the ECM a quick rap and see if things improve?
Have you tried scanning it and seeing what the ECM sees for IAC counts? Assuming you are right on the spark plug wires.
Have you checked fuel pressure? Spark quality? All injector wires good? Give the ECM a quick rap and see if things improve?
Le Mans Master
Joined: Dec 2005
Posts: 8,559
Likes: 942
From: Communist Colorado
96 LT1 collectors edition. I replaced front engine seals, rebuilt opti spark, water pump,plugs, wires. Car barely idles now with no acceleration. Tried new temp sensor with pig tail no difference. Re checked wires firing order all good. I do not have alternater hooked up do to 3wire plug damaged. New one on way. Any ideas greatly appreciated. Car ran perfectly fine before this. Thanks
Thread Starter
7th Gear
Joined: Sep 2017
Posts: 7
Likes: 0
From: Coarsegold Ca
Crank seal was leaking. Has 90,000 miles all original. Opti spark had crack across face so installed new rebuilt one,water pump,plugs, wires. Battery power only right now, just wanted to start it and make sure it would run.
Thread Starter
7th Gear
Joined: Sep 2017
Posts: 7
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From: Coarsegold Ca
Tried to run scan. No codes. Engine idles little while about 500rpm then dies. Will not rev up or run long enough to bring a code. Old opti did work. Take apart again tomorrow put old opti spark back in see what happens
Team Owner
Joined: Jul 2004
Posts: 28,416
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From: Hartford WI
If you want, turn the idle adjustment screw in till you get a stable idle and scan. Don't care about the codes yet. See what you can get for IAC count with engine at stable operating temp and everything but the motor off. Report back
Thread Starter
7th Gear
Joined: Sep 2017
Posts: 7
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From: Coarsegold Ca
One question. I do not have alternator hooked up due to broken 3wire plug. Could this be the cause of my problem ? Running on battery power just to see if engine ran after repairs. New alternator plug on way.
Team Owner
Joined: Jul 2004
Posts: 28,416
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From: Hartford WI
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Team Owner
Joined: Jul 2004
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From: Hartford WI
Thread Starter
7th Gear
Joined: Sep 2017
Posts: 7
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From: Coarsegold Ca
When replacing crank seal noticed crack in face of opti spark and burned spot. 90000miles so figured replace it while pump off. Don't know if alternator had to be hooked up to complete some circuit
Team Owner
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From: Hartford WI
Melting Slicks
Joined: Oct 2016
Posts: 2,024
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From: Central Alabama
If I'm understanding correctly, the car was running fine except for an oil leak.
Now it barely runs.
So the most likely causes are a bad part, or something got put together wrong or damaged.
I'd look at every connector that was touched. Lots of stuff gets disconnected getting to the opti. Could be a connector, say the TPS or IAC connector is loose. A wire could have been broken.
And yes you could have crossed wires. I was absolutely certain my wires were right, except they weren't.
You mentioned a new rebuilt opti. What was the source?
Now it barely runs.
So the most likely causes are a bad part, or something got put together wrong or damaged.
I'd look at every connector that was touched. Lots of stuff gets disconnected getting to the opti. Could be a connector, say the TPS or IAC connector is loose. A wire could have been broken.
And yes you could have crossed wires. I was absolutely certain my wires were right, except they weren't.
You mentioned a new rebuilt opti. What was the source?
Racer
Joined: Sep 2017
Posts: 452
Likes: 55
From: Marianna Fl
Sounds like 1 of 2 things. weak or improperly timed spark or that the IAC valve is not working properly. The last LT1 I rebuild would idle at 450rpm and was very hard to bring up because of a bad IAC valve AND a bad opti.