1987 350TPI randomly cuts out?
04-06-2021, 04:14 AM
#1
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Car: 1987 Trans Am GTA
Engine: L98 5.7L
Transmission: 700-R4
Axle/Gears: GW6 3.27
1987 350TPI randomly cuts out?
Hey again gang, still wrenching on the '87 GTA, so close to having it on the road, but now have run into this issue I can't seem to find elsewhere.
So what is currently happening now, is the car will randomly shut off after driving for a short time, and when you go to restart it, the check engine light does not turn back on, so you can't star the car again.
It's not like a slow stall, it will just suddenly without warning, just turn off. Not splutter and choke as if it wasn't getting enough fuel, just quickly and quietly turn off. I don't think it's a fuel problem, even though filter was really bad, after all that was changed & it ran better, but still randomly shut off.
The car previously had a dodgy immobilizer in it, but it was completely stripped and removed, now has a current decent immobilizer in it. It was not an issue before with the old immobilizer. When checking power to the injectors/fuel rail, there is no power at all when the check engine light is not there, but, both sides of ignition have good strong power. Re-assessed all the grounds in the car and on the block, made sure those were sold.
What is weird, is when you mucked around with the fuse box or something under the dash and just moved it/adjusted it/shuffled it around, the check engine light would then come back on. I don't think it is the ECU, it looks like it is brand spanking new, but is the original one that came with the car. Maybe a contact of some sort? But all the connections are good. Opened it up, checked the circuit board, it's in better shape then the one in my 1998 Honda Prelude. Don't know how to properly check for codes with the OBU port but kinda get the idea with a paperclip, but haven't seen any codes come up. Also, is the computer supposed to get that hot??? It was really hot when removed after the car was idling for 20 mins waiting for the motor to cut out.
Has it got anything to do with the injectors? Some sort of shutoff signal from the ECU maybe? What could be the problem? Any ideas?
So what is currently happening now, is the car will randomly shut off after driving for a short time, and when you go to restart it, the check engine light does not turn back on, so you can't star the car again.
It's not like a slow stall, it will just suddenly without warning, just turn off. Not splutter and choke as if it wasn't getting enough fuel, just quickly and quietly turn off. I don't think it's a fuel problem, even though filter was really bad, after all that was changed & it ran better, but still randomly shut off.
The car previously had a dodgy immobilizer in it, but it was completely stripped and removed, now has a current decent immobilizer in it. It was not an issue before with the old immobilizer. When checking power to the injectors/fuel rail, there is no power at all when the check engine light is not there, but, both sides of ignition have good strong power. Re-assessed all the grounds in the car and on the block, made sure those were sold.
What is weird, is when you mucked around with the fuse box or something under the dash and just moved it/adjusted it/shuffled it around, the check engine light would then come back on. I don't think it is the ECU, it looks like it is brand spanking new, but is the original one that came with the car. Maybe a contact of some sort? But all the connections are good. Opened it up, checked the circuit board, it's in better shape then the one in my 1998 Honda Prelude. Don't know how to properly check for codes with the OBU port but kinda get the idea with a paperclip, but haven't seen any codes come up. Also, is the computer supposed to get that hot??? It was really hot when removed after the car was idling for 20 mins waiting for the motor to cut out.
Has it got anything to do with the injectors? Some sort of shutoff signal from the ECU maybe? What could be the problem? Any ideas?
04-06-2021, 04:52 PM
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Re: 1987 350TPI randomly cuts out?
Hey again gang, still wrenching on the '87 GTA, so close to having it on the road, but now have run into this issue I can't seem to find elsewhere.
So what is currently happening now, is the car will randomly shut off after driving for a short time, and when you go to restart it, the check engine light does not turn back on, so you can't star the car again.
It's not like a slow stall, it will just suddenly without warning, just turn off. Not splutter and choke as if it wasn't getting enough fuel, just quickly and quietly turn off. I don't think it's a fuel problem, even though filter was really bad, after all that was changed & it ran better, but still randomly shut off.
The car previously had a dodgy immobilizer in it, but it was completely stripped and removed, now has a current decent immobilizer in it. It was not an issue before with the old immobilizer. When checking power to the injectors/fuel rail, there is no power at all when the check engine light is not there, but, both sides of ignition have good strong power. Re-assessed all the grounds in the car and on the block, made sure those were sold.
What is weird, is when you mucked around with the fuse box or something under the dash and just moved it/adjusted it/shuffled it around, the check engine light would then come back on. I don't think it is the ECU, it looks like it is brand spanking new, but is the original one that came with the car. Maybe a contact of some sort? But all the connections are good. Opened it up, checked the circuit board, it's in better shape then the one in my 1998 Honda Prelude. Don't know how to properly check for codes with the OBU port but kinda get the idea with a paperclip, but haven't seen any codes come up. Also, is the computer supposed to get that hot??? It was really hot when removed after the car was idling for 20 mins waiting for the motor to cut out.
Has it got anything to do with the injectors? Some sort of shutoff signal from the ECU maybe? What could be the problem? Any ideas?
So what is currently happening now, is the car will randomly shut off after driving for a short time, and when you go to restart it, the check engine light does not turn back on, so you can't star the car again.
It's not like a slow stall, it will just suddenly without warning, just turn off. Not splutter and choke as if it wasn't getting enough fuel, just quickly and quietly turn off. I don't think it's a fuel problem, even though filter was really bad, after all that was changed & it ran better, but still randomly shut off.
The car previously had a dodgy immobilizer in it, but it was completely stripped and removed, now has a current decent immobilizer in it. It was not an issue before with the old immobilizer. When checking power to the injectors/fuel rail, there is no power at all when the check engine light is not there, but, both sides of ignition have good strong power. Re-assessed all the grounds in the car and on the block, made sure those were sold.
What is weird, is when you mucked around with the fuse box or something under the dash and just moved it/adjusted it/shuffled it around, the check engine light would then come back on. I don't think it is the ECU, it looks like it is brand spanking new, but is the original one that came with the car. Maybe a contact of some sort? But all the connections are good. Opened it up, checked the circuit board, it's in better shape then the one in my 1998 Honda Prelude. Don't know how to properly check for codes with the OBU port but kinda get the idea with a paperclip, but haven't seen any codes come up. Also, is the computer supposed to get that hot??? It was really hot when removed after the car was idling for 20 mins waiting for the motor to cut out.
Has it got anything to do with the injectors? Some sort of shutoff signal from the ECU maybe? What could be the problem? Any ideas?
I had it towed to the dealer after that. Thankfully, they somehow found it pretty fast. Issue was that somebody had soldered a fuseable link that was connected
to the starter. It would periodically cause a sudden shutdown.
04-08-2021, 07:38 AM
#3
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Join Date: Feb 2021
Location: Sydney, Australia
Posts: 33
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Car: 1987 Trans Am GTA
Engine: L98 5.7L
Transmission: 700-R4
Axle/Gears: GW6 3.27
Re: 1987 350TPI randomly cuts out?
Well, I found the problem. Ended up being something super simple. Faulty new immobilizer. Fixed lol
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