LT1 Ignition Issues
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Intermediate
Joined: May 2003
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From: TX
LT1 Ignition Issues
I have had issues last week with my engine stalling on highway three times and restarting first try and continuing. The following day engine started for one second then shut off 4 time before starting. Changed clogged fuel pump and worked fine for one day then did the three times starting and shutting down again. Now it has been working without failure for three days. I have check all connections relays coil, fuel pressure you name it. I finally had a friend bring home a OBD1 computer and it had a code 42 Electronic Spark Timing Circuit.(EST) short to ground.
The coded definition tells you to check wiring at the ignition module. or Replace ignition module. PossibleECM failure.
I assume the ignition module is the one by the coil in front of the valve cover passenger side? Correct and that does not mean replace the distributor? I should probably clear the code and see if it appears again wondering if oil leaking could of caused the short to ground condition.
The coded definition tells you to check wiring at the ignition module. or Replace ignition module. PossibleECM failure.
I assume the ignition module is the one by the coil in front of the valve cover passenger side? Correct and that does not mean replace the distributor? I should probably clear the code and see if it appears again wondering if oil leaking could of caused the short to ground condition.
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From: Fort Knox, KY
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You don't necessarily have to replace the distributor. Check the wire that runs from the coil to it, though.
When you replace the ICM, be sure and coat the back of it with the packet of thermal heat transfer grease that comes with it. Your new ICM will stir-fry horribly to death without it.
When you replace the ICM, be sure and coat the back of it with the packet of thermal heat transfer grease that comes with it. Your new ICM will stir-fry horribly to death without it.
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From: TX
Should I replace the ECM right away or see if I have the problem again and check for another code. And what about the short to ground? My concern is if oil caused the short to ground will it do it again?
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Originally Posted by Mastercraft
Should I replace the ECM right away or see if I have the problem again and check for another code. And what about the short to ground? My concern is if oil caused the short to ground will it do it again?
I don't want to see you throw money at parts, but an ignition control module (ICM) and coil combined are a lot cheaper than a new or reman ECM. You can have your ICM tested at an auto parts store.
Team Owner
Joined: Aug 2000
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From: San Pedro CA
Whatever you do, don't replace parts at random... all it will do is make your wallet lighter.
The module is a great place to start...
did you have a bad fuel pump or filter?
Also, check the harnesses that connect to the ICM. They are known to fail/weaken and make poor connections.
The module is a great place to start...
did you have a bad fuel pump or filter?
Also, check the harnesses that connect to the ICM. They are known to fail/weaken and make poor connections.
Melting Slicks
Joined: Dec 2000
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From: Fremont Oh
I had a situation where the coil connector ( not wire) was intermittant, I'd romp on the car it would die,I pull off the side of the road wiggle a few wires it would fire up...
One day with the hood open working in the garage with the engine running I bumpd the connector the engine died... the connectors stink theyy do not hold tension and carbon track as well...
Waht you are saying sounds alot like the symptoms I had at that time..
MO
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From: TX
I will check all connections first. Since it doesn't do it often at all it could be a connection. I replaced the fuel filter and it was very clogged. Today my sons 97 Z28 camaro quit on the road. After towing it home I found great spark from the coil and light orange to the plug. I removed the distributor and both seals were leaking on the distributor from the water pump seal and dist seal. I took a chance and replaced the distributer and that fixed the whole problem. My vette next. But his quit and woild not even fire until I replaced the dist.
