car just shut of while driving
Banned
Joined: Jan 2013
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From: Las Vegas
Intermittent problems can be the most difficult to troubleshoot. It seems like your problem is down at the opti connector or the opti itself. My read is your down to replacing either the engine harness or the opti.
When i reflashed my PCM on my '94 this year the wiring connectors were feeling a little brittle but its still functional after 20 years. I dont recommend wiggling wires too much to troubleshoot because sometimes u end up with loose and broken connectors/wires u didnt have before. Myself i would just find all the ground wires to the body metal and clean them for a good contact surface then as time permits replace the opti then the engine harness.
I dont see how selling your hot rod is a fix. Every old car has problems that u need to learn and understand to master. A shop manual and scanner will help and the more u use them the more helpful they become. Selling and starting over and over again is much more expensive. Trying to reduce to just one hot rod LT1 would help finances enough but like most us enthusiasts without a hobby car u will just be looking for another.
Good luck Brian,
cardo
When i reflashed my PCM on my '94 this year the wiring connectors were feeling a little brittle but its still functional after 20 years. I dont recommend wiggling wires too much to troubleshoot because sometimes u end up with loose and broken connectors/wires u didnt have before. Myself i would just find all the ground wires to the body metal and clean them for a good contact surface then as time permits replace the opti then the engine harness.
I dont see how selling your hot rod is a fix. Every old car has problems that u need to learn and understand to master. A shop manual and scanner will help and the more u use them the more helpful they become. Selling and starting over and over again is much more expensive. Trying to reduce to just one hot rod LT1 would help finances enough but like most us enthusiasts without a hobby car u will just be looking for another.
Good luck Brian,
cardo
Thread Starter
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Joined: Feb 2012
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From: Long Beach, MS
Just going to update this thread to keep a record of every time it happens and what if anything I do to get it running again.
Car died while driving to work today, I coasted to a stop and then when I turned the key back on I didn't hear the fuel pump kick on. So i turned the key off and back on and still didn't hear anything, cranked it anyway and it fired right up and drove the rest of the way with no issues. Didn't actually do anything to get it to start.
Car died while driving to work today, I coasted to a stop and then when I turned the key back on I didn't hear the fuel pump kick on. So i turned the key off and back on and still didn't hear anything, cranked it anyway and it fired right up and drove the rest of the way with no issues. Didn't actually do anything to get it to start.
Thread Starter
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Joined: Feb 2012
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From: Long Beach, MS
It died last night. I couldn't get it to start for anything. It appears that it is getting spark, but either the fuel pump is not providing enough pressure or the injectors are not firing. I thought finally I'll be able to figure this out. This morning I got back to the car and it fired right up. Going to put a fuel pressure gauge on it this weekend and check that out.
I could get it to try to fire by messing with the opti pigtail, the end near the manifold. If I unplug it with the key on I can hear a relay click and a buzzing sound for a few seconds. If i did this it would fire for a split second like maybe only a cylinder or two had gotten some fuel. IDK just weird.
I hate intermittent problems!
I could get it to try to fire by messing with the opti pigtail, the end near the manifold. If I unplug it with the key on I can hear a relay click and a buzzing sound for a few seconds. If i did this it would fire for a split second like maybe only a cylinder or two had gotten some fuel. IDK just weird.
I hate intermittent problems!
my car did the same thing when it had a opti. found out that the icm ground wire wasn't good. car drove fine then would die for 20 min then turn back on, one of the times it died I had a extra piece of wire and made a temporary ground and it worked, the car never died again.
Thread Starter
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Joined: Feb 2012
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From: Long Beach, MS
So looks like I had a short in the wiring between the ICM and the coil. I replaced the ICM connector with a new one and snagged a good coil plug at the u-pullit.
While I was at the u-pullit to get the coil connector I found a t-top headliner in excellent condition cost $10
While I was at the u-pullit to get the coil connector I found a t-top headliner in excellent condition cost $10
On The Tree
Joined: May 2008
Posts: 191
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From: Ontario, Canada
So looks like I had a short in the wiring between the ICM and the coil. I replaced the ICM connector with a new one and snagged a good coil plug at the u-pullit.
While I was at the u-pullit to get the coil connector I found a t-top headliner in excellent condition cost $10
While I was at the u-pullit to get the coil connector I found a t-top headliner in excellent condition cost $10
Thread Starter
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From: Long Beach, MS
Will not know until I get to drive it a while and it doesn't happen.
One thing I can be sure of, if I pushed down on the wire going into the coil connector from the ICM the car would die. Then it would most likely fire right back up. The couple of times it didn't fire while I was concentrating on that area, I could go and pull up on the wire and it would crank right up.
I have a good feeling that this was the issue. My wiring harness is pretty ratty near all the connectors, so I'm looking forward to more issues like this. So far I've replaced the coolant temp sensor connector, ICM connector, and coil connector (grey). Thinking the MAF connector will be next on the list.
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Joined: May 2008
Posts: 191
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From: Ontario, Canada
Not yet. lol
Will not know until I get to drive it a while and it doesn't happen.
One thing I can be sure of, if I pushed down on the wire going into the coil connector from the ICM the car would die. Then it would most likely fire right back up. The couple of times it didn't fire while I was concentrating on that area, I could go and pull up on the wire and it would crank right up.
I have a good feeling that this was the issue. My wiring harness is pretty ratty near all the connectors, so I'm looking forward to more issues like this. So far I've replaced the coolant temp sensor connector, ICM connector, and coil connector (grey). Thinking the MAF connector will be next on the list.
Will not know until I get to drive it a while and it doesn't happen.
One thing I can be sure of, if I pushed down on the wire going into the coil connector from the ICM the car would die. Then it would most likely fire right back up. The couple of times it didn't fire while I was concentrating on that area, I could go and pull up on the wire and it would crank right up.
I have a good feeling that this was the issue. My wiring harness is pretty ratty near all the connectors, so I'm looking forward to more issues like this. So far I've replaced the coolant temp sensor connector, ICM connector, and coil connector (grey). Thinking the MAF connector will be next on the list.
It sounds like you've possibly found the problem. Thanks for keeping this thread alive and updating as you troubleshoot the problem. Good information for me to go off of with an issue I had with my car doing something similar but it was only when I would sit at a light or stop sign. Now I'm wondering if its also related to the electrical drain problem I haven't been able to figure out.
Thread Starter
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From: Long Beach, MS
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaahhhhhhhhh 
Definitely not fixed.
Car died on the way to work this morning. Just shut off with no warning. I sat and tried to start it, but nothing. Then I sat for a couple minutes and tried again and it started up like nothing had happened.
Definitely not fixed.
Car died on the way to work this morning. Just shut off with no warning. I sat and tried to start it, but nothing. Then I sat for a couple minutes and tried again and it started up like nothing had happened.
Sounds like Optispark is slow dieing.
I highly recommend getting an AC Delco or Delphi unit and then doing the LTCC conversion.
Its has a personal experience with my car. had to change optis like 2-3 times a year.
So on the fourth i decided to go AC Delco and did the LTCC. Has been running like a champ for the past 10 months. anyways those are my 2 cents.
I highly recommend getting an AC Delco or Delphi unit and then doing the LTCC conversion.
Its has a personal experience with my car. had to change optis like 2-3 times a year.
So on the fourth i decided to go AC Delco and did the LTCC. Has been running like a champ for the past 10 months. anyways those are my 2 cents.
Thread Starter
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Joined: Feb 2012
Posts: 419
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From: Long Beach, MS
Sounds like Optispark is slow dieing.
I highly recommend getting an AC Delco or Delphi unit and then doing the LTCC conversion.
Its has a personal experience with my car. had to change optis like 2-3 times a year.
So on the fourth i decided to go AC Delco and did the LTCC. Has been running like a champ for the past 10 months. anyways those are my 2 cents.
I highly recommend getting an AC Delco or Delphi unit and then doing the LTCC conversion.
Its has a personal experience with my car. had to change optis like 2-3 times a year.
So on the fourth i decided to go AC Delco and did the LTCC. Has been running like a champ for the past 10 months. anyways those are my 2 cents.
Thread Starter
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From: Long Beach, MS
Just wish it would stay not running long enough for me to troubleshoot.
I'm always alone and cant even check for spark.
Guess when I get paid again i'll rent a fuel pressure guage and tape it to the windshield and hope it dies within a week or so.
I'm always alone and cant even check for spark.
Guess when I get paid again i'll rent a fuel pressure guage and tape it to the windshield and hope it dies within a week or so.
Thread Starter
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From: Long Beach, MS
I tested the fuel pressure this weekend, and though it didn't die while I was testing, the pressure was 42 KOEO and about 32 Idling. Went up to about 45 with the FPR unplugged. So I'm thinking the pump is good.
The car has started to cut out bad at full throttle, missing and backfiring, etc... so I'm replacing the opti. Maybe that will fix the issue, maybe not. My wife's exact word were "well it's not the opti's fault that you dumped coolant on it twice now" :/
The car has started to cut out bad at full throttle, missing and backfiring, etc... so I'm replacing the opti. Maybe that will fix the issue, maybe not. My wife's exact word were "well it's not the opti's fault that you dumped coolant on it twice now" :/
LOL...95% of these issues are either ICM or Opti related, one time my coil went out too....I've been through these tribulations many times it is frustrating to say the least; however that's the nature of the beast! You just have suck it up and hopefully get a quality opti and get good at replacing it or go the the LTCC conversion or better yet, swap in a LS instead! LT1's are not for everyone, it reminds me a lot of my antique British sports car 
Launching!
Joined: Nov 2012
Posts: 206
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From: Bowling Green
Well, I officially sold my Formula. This guy claimed to know almost everything about LT1s and he could never figure out what the problem was. He asked for my best guess. I said change the opti. He changed it... and it fixed the problem. It hasn't died on him yet. My problem was I was using a $230 Cardone distributor. He bought a $509 MSD distributor.
Well, I officially sold my Formula. This guy claimAC Delco or MSD or you are asking for trouble...both being over $500.ed to know almost everything about LT1s and he could never figure out what the problem was. He asked for my best guess. I said change the opti. He changed it... and it fixed the problem. It hasn't died on him yet. My problem was I was using a $230 Cardone distributor. He bought a $509 MSD distributor.
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From: Long Beach, MS
Well, been driving for almost a week now and it has not died on me. Hoping that I have it fixed.
I replaced both the opti and the coil. I think my coil may have been the culprit. I got on it the other day and the motor would just fall on it's face and cut out above about 4000 rpm when going WOT. I replaced the coil and it's stopped doing that. So it may have just been bad.
I also replaced the opti, even though the one that was on there looked really clean on the inside. There was a lot of what looks like carbon buildup on the posts in the cap. I ended up disassembling the new opti and putting my original mitsubishi sensor in it. I just cleaned all the rust out of the optics. It's running pretty good now.
Time will tell.
I replaced both the opti and the coil. I think my coil may have been the culprit. I got on it the other day and the motor would just fall on it's face and cut out above about 4000 rpm when going WOT. I replaced the coil and it's stopped doing that. So it may have just been bad.
I also replaced the opti, even though the one that was on there looked really clean on the inside. There was a lot of what looks like carbon buildup on the posts in the cap. I ended up disassembling the new opti and putting my original mitsubishi sensor in it. I just cleaned all the rust out of the optics. It's running pretty good now.
Time will tell.
Thread Starter
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Joined: Feb 2012
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From: Long Beach, MS
well, I'm calling this issue fixed. Hasn't died in almost a month. I replaced the coil and the opti. Not positive which of these fixed it, but it's fixed.
I actually enjoy driving the car now that it doesn't randomly die.
Of course it also makes it more enjoyable that I fixed two oil leaks, a trans leak, got new tires, fixed the windshield wipers, opti, coil, spark plugs, alternator, exhaust leaks, new O2s, and some long tubes.
I actually enjoy driving the car now that it doesn't randomly die.
Of course it also makes it more enjoyable that I fixed two oil leaks, a trans leak, got new tires, fixed the windshield wipers, opti, coil, spark plugs, alternator, exhaust leaks, new O2s, and some long tubes.