Why are you dying?!
Thread Starter
3rd Gear
Joined: Oct 2014
Posts: 3
Likes: 0
From: Austin TX
Why are you dying?!
I'm new, but like to read through the threads from time to time and am thankful for the info I see here.
Looking for some ideas from y'all. I have a '94 LT1 Coupe (94K miles) which starts, runs fine for a few miles then dies suddenly. All power to instrumentation, windows, radio etc stay on, but engine dies completely. The last time I was able to get her restarted just long enough to get through the intersection. Tried and tried afterward to restart and got nowhere until 20 minutes later when the wrecker showed up. Then, bam, fired right up. When the car was being diagnosed at Austin Corvette, they couldn't get the car to die at all. Everything seemed to check out fine which led them to believe it is related to the ECM, I'm fine replacing it, but then got some advice questioning whether it could be related to the security system, something which would cause the motor to completely cut-out but all other electronics to keep working. I know the factory security has a delay before the car will start again.
I'm hoping someone will have some insight or have experienced something similar. I'm happy to answer any follow-up questions if they would be helpful in narrowing down the problem. I've replaced a ton of parts over the last year and just want my reliable baby back.
Thank you in advance.
Tigh
Looking for some ideas from y'all. I have a '94 LT1 Coupe (94K miles) which starts, runs fine for a few miles then dies suddenly. All power to instrumentation, windows, radio etc stay on, but engine dies completely. The last time I was able to get her restarted just long enough to get through the intersection. Tried and tried afterward to restart and got nowhere until 20 minutes later when the wrecker showed up. Then, bam, fired right up. When the car was being diagnosed at Austin Corvette, they couldn't get the car to die at all. Everything seemed to check out fine which led them to believe it is related to the ECM, I'm fine replacing it, but then got some advice questioning whether it could be related to the security system, something which would cause the motor to completely cut-out but all other electronics to keep working. I know the factory security has a delay before the car will start again.
I'm hoping someone will have some insight or have experienced something similar. I'm happy to answer any follow-up questions if they would be helpful in narrowing down the problem. I've replaced a ton of parts over the last year and just want my reliable baby back.
Thank you in advance.
Tigh
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
It is NOT the VATS (security). Impossible. Once the handshake between the CCM and PCM takes place, they are forever linked until the next startup. So that's not it.
I will bet money it is the harness to the coil. The plastic bits wear out and loose contact. There are a number of connections between the coil and the Ignition Control Module (ICM) that if they fail, will result in things ending suddenly. Heat and vibration are required to make this fail.
I will bet money it is the harness to the coil. The plastic bits wear out and loose contact. There are a number of connections between the coil and the Ignition Control Module (ICM) that if they fail, will result in things ending suddenly. Heat and vibration are required to make this fail.
Team Owner
Joined: Sep 2003
Posts: 25,394
Likes: 2,741
http://tech.corvettecentral.com/2011...trouble-codes/
The harnesses from the opti to the coil and the ICM certainly deserve conversation and checking. The opti harness I believe is less than $40 from most vendors and the condition of the other connectors could be checked and verified.
Post the list of parts replaced first I believe the best start for now.
Thread Starter
3rd Gear
Joined: Oct 2014
Posts: 3
Likes: 0
From: Austin TX
Post the list of parts replaced first I believe the best start for now.
Thanks for the input.
Over the last year and a half I've replaced:
Water pump
Opti-Spark
Wires and plugs
Coil and ignition module
Intake manifold gasket
Brake booster
Wheel hubs
Valve cover gaskets
Vacuum lines
Key fob
Some of these are definitely unrelated to current issue.
I've had three different shops perform the work, most of the parts have been AC Delco unless aftermarket was the only thing available at the time. I've trusted Austin Corvette for years and they looked at the car last. Said they did wiggle tests and checked all the likely connections, ran the codes and basically said the only thing left to try is the computer. Only code showing is #26.
Thanks for the input.
Over the last year and a half I've replaced:
Water pump
Opti-Spark
Wires and plugs
Coil and ignition module
Intake manifold gasket
Brake booster
Wheel hubs
Valve cover gaskets
Vacuum lines
Key fob
Some of these are definitely unrelated to current issue.
I've had three different shops perform the work, most of the parts have been AC Delco unless aftermarket was the only thing available at the time. I've trusted Austin Corvette for years and they looked at the car last. Said they did wiggle tests and checked all the likely connections, ran the codes and basically said the only thing left to try is the computer. Only code showing is #26.
Safety Car
Joined: Apr 2011
Posts: 3,660
Likes: 22
If possible, see if the Corvette shop will "loan" you an ECM for a few days to try and see if that fixes the problem, since that what they are recommending. If it does, then they get to sell you an ECM....if not, then they get to keep doing diagnostics...its a win-win for the shop. Either way they make money. And, you get your car fixed....eventually.
This sounds like a cold-joint on a circuit board or a harness issue. I had a VATS module with a loose transistor that you had to 'tap' to start the car....I would think the ECM could have similar issues...hit the right bump, a circuit is broken killing the ignition for a split second. That's all it takes.
This sounds like a cold-joint on a circuit board or a harness issue. I had a VATS module with a loose transistor that you had to 'tap' to start the car....I would think the ECM could have similar issues...hit the right bump, a circuit is broken killing the ignition for a split second. That's all it takes.
