Car starts great, runs great, warms up and shuts off
#1
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Car: 1989 IROC-Z
Engine: 5.0L
Transmission: 5spd M5
Axle/Gears: 3.45 Borg Warner
Car starts great, runs great, warms up and shuts off
Love my 89 IROC 5.0 TPI, had it for 28 years. It sat for a couple years, then drove it for a bit, then it sat again for several years. But now I have moved to a new home, and I was able to drive it the 30 minute drive from my old place to my new place. During that drive, it started to run rough when I got close to the new place, but it did not die.
But last week, I took it out for a drive, and it ran perfectly fine, through warm up and for a bit after, until I decided to step on the gas a bit. As soon as I did that, the engine completely shut off. It seemed like it just suddenly had no spark or something. It would not start at all. I pushed it to the side of the road and let it cool down for about 4 hours. When I came back, it started right up. I replicated the issue yesterday. Exactly the same thing. Runs fine during warmup and for a while after, and then when I step on the gas, it dies. I have to let it cool down before it will start again.
Does anybody have any idea what is going on? Ignition coil? Distributor? God, I hope it's not the ECM. I am assuming it is a spark issue, only because I don't think it would quit so suddenly if it was a fuel issue. It would at least chug a bit, then die.
But last week, I took it out for a drive, and it ran perfectly fine, through warm up and for a bit after, until I decided to step on the gas a bit. As soon as I did that, the engine completely shut off. It seemed like it just suddenly had no spark or something. It would not start at all. I pushed it to the side of the road and let it cool down for about 4 hours. When I came back, it started right up. I replicated the issue yesterday. Exactly the same thing. Runs fine during warmup and for a while after, and then when I step on the gas, it dies. I have to let it cool down before it will start again.
Does anybody have any idea what is going on? Ignition coil? Distributor? God, I hope it's not the ECM. I am assuming it is a spark issue, only because I don't think it would quit so suddenly if it was a fuel issue. It would at least chug a bit, then die.
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Car: 92 Firebird, 77 Trans Am SE, 86 Z28
Engine: 5.7 HSR, T/A 6.6, empty
Transmission: T-5, TH350, T-5
Axle/Gears: 3.08 posi, 3.23 posi, 3.23
Re: Car starts great, runs great, warms up and shuts off
Test for spark, fuel pressure and injector pulse. Needs those to run and likely one failed. Purely guessing by anecdotal information, the icm in the distributor is dying from heat.
And I see way too late that Tuned already replied that Well, he knows as well as the rest of us, if not more so.
And I see way too late that Tuned already replied that Well, he knows as well as the rest of us, if not more so.
#4
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Car: 1989 IROC-Z
Engine: 5.0L
Transmission: 5spd M5
Axle/Gears: 3.45 Borg Warner
Re: Car starts great, runs great, warms up and shuts off
I replaced the ICM, but the issue persisted. I then went ahead and replaced the rotor, distributor cap and ignition coil, as these can all be susceptible to overheating, and because they are cheap to replace. The issue persists. One thing I did notice... it smells like unburned fuel (I think that's what I'm smelling) when it is warming up, and once it is warmed, I can rev it up, and I hear popping and banging from the exhaust, which I believe is unburned fuel igniting in the cats, now that they are hot. This is why I am convinced that it is an ignition issue somewhere. Could I be wrong? Could it still be a fuel issue?
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#6
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Car: 1989 IROC-Z
Engine: 5.0L
Transmission: 5spd M5
Axle/Gears: 3.45 Borg Warner
Re: Car starts great, runs great, warms up and shuts off
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#8
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Car: 1989 IROC-Z
Engine: 5.0L
Transmission: 5spd M5
Axle/Gears: 3.45 Borg Warner
Re: Car starts great, runs great, warms up and shuts off
How would failed injectors account for the unburned fuel in the exhaust?
#10
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Car: 1989 IROC-Z
Engine: 5.0L
Transmission: 5spd M5
Axle/Gears: 3.45 Borg Warner
Re: Car starts great, runs great, warms up and shuts off
If it's getting plenty of air, but not enough fuel, would you get unburned fuel coming out the exhaust? If that's possible, then yeah, I guess it could be lean. But it seems counter-intuitive to have unburned fuel if there is not enough fuel.
#11
Re: Car starts great, runs great, warms up and shuts off
condensation or raw fuel coming out? Don’t see why is so hard to ohm the injectors. Check fuel pressure. Leaking or shorted coils or old injectors just not flowing well all are possibilities. But if you insist it’s ignition related good luck with fixing it.
#12
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Car: 1989 IROC-Z
Engine: 5.0L
Transmission: 5spd M5
Axle/Gears: 3.45 Borg Warner
Re: Car starts great, runs great, warms up and shuts off
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Car: 1989 IROC-Z 305 LB9 AT Convertible
Engine: LB9 305
Transmission: AT
Re: Car starts great, runs great, warms up and shuts off
My first, of 3 First Gen F Bodies, died when warm with no restart. It came with a Repair Shop work order, stating the problem was bad Injectors. I was unfamiliar with GM Multec injectors and replaced the coil, distributor pickup, etc., with no change.
I replaced the injectors and problem was solved. Live and learn!
Check FI Injectors resistance, Buddy!
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