'88 IROC LB9 Runs Perfect for Hours....then won't START!
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Car: 1988 IROC Z28
Engine: 305 H.O. LB9
Transmission: T5 5-Speed
Axle/Gears: 3.45
'88 IROC LB9 Runs Perfect for Hours....then won't START!
Hey guys, I'm having trouble with my 72k mile '88 IROC. It starts up just fine, it will run perfect for as long as I drive it (10 min. to 3 hrs.)......BUT.....as soon as I turn it off, it will not start. It has spark, there is fuel at the schrader valve on the fuel rail, and nothing in the air intake is restricted. If I try to re start it after a couple minutes it will fire, run like crap (500-900 rpm), it will not respond to any throttle input, and then die. If I let it sit 15-30 minutes it will start right up, run perfect again until I shut it off, and then the whole process starts over again. The IAC was loose (I unscrewed it by hand), I replaced it with a new one and it does the same thing. Any ideas would be appreciated, I kinda spent my budget on the car and don't have a whole lot of $$$ left to play with.
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Car: 98 camaro ss, 98 grand cherokee 5sp
Engine: 5.7 ls1, 4.0 sixxer
Transmission: T56, ax15 swapped
Axle/Gears: 3.42, 3.73
Re: '88 IROC LB9 Runs Perfect for Hours....then won't START!
check your fuel pressure,KOEO, and with the car running. Check for pressure drop, should hold pressure for at least 5 minutes i would say. My guess is your pressure is low.
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Car: 1987 Trans Am
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Re: '88 IROC LB9 Runs Perfect for Hours....then won't START!
It could also be the injectors, I would check the ohms when the car won't start. It should be around 14 ohms, no less than 10...
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Car: 1988 IROC Z28
Engine: 305 H.O. LB9
Transmission: T5 5-Speed
Axle/Gears: 3.45
Re: '88 IROC LB9 Runs Perfect for Hours....then won't START!
I forgot to mention that I already ohm checked the injectors and they all looked good, really good actually. I just got done replacing the fuel filter so I thought I would fire it up to see if I had any leaks. I had my wife turn the igintion key to on, and I felt the pump relay kick in and heard the pump run for 2-3 seconds. It fired right up and ran fine. After about a minute I had her shut it off, then turn the key to ignition on again. This time no click from the relay, no fuel pump, and no start. I'm going to change the relay tomorrow......hopefully that's the issue?!? (I'm also picking up the adaptor for my fuel pressure tool so I can check that too) Thanks for the help so far guys.
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Car: 1988 IROC Z28
Engine: 305 H.O. LB9
Transmission: T5 5-Speed
Axle/Gears: 3.45
Re: '88 IROC LB9 Runs Perfect for Hours....then won't START!
Ok, I changed the fuel pump relay and it started and ran great. I cycled it 14 times.....5 minutes running, 1-5 minutes off, restart. It worked great. Then the 15th time no start. When it was starting good it had 46lbs. fuel pressure w/ key on-engine off, and it had 41lbs. while running. The last restart it lost all pressure while running and died. Then with the key on and engine off it didn't build any pressure at all. I've read of similar problems solved by changing the ECM in the distrubitor, but I can't keep throwing parts ($$$) at it. It really seems like the pump is good, but it's not getting power. Any ideas?
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Re: '88 IROC LB9 Runs Perfect for Hours....then won't START!
Ok, I changed the fuel pump relay and it started and ran great. I cycled it 14 times.....5 minutes running, 1-5 minutes off, restart. It worked great. Then the 15th time no start. When it was starting good it had 46lbs. fuel pressure w/ key on-engine off, and it had 41lbs. while running. The last restart it lost all pressure while running and died. Then with the key on and engine off it didn't build any pressure at all. I've read of similar problems solved by changing the ECM in the distrubitor, but I can't keep throwing parts ($$$) at it. It really seems like the pump is good, but it's not getting power. Any ideas?
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Car: 1988 IROC Z28
Engine: 305 H.O. LB9
Transmission: T5 5-Speed
Axle/Gears: 3.45
Re: '88 IROC LB9 Runs Perfect for Hours....then won't START!
Thank you everyone for the help. I think I've narrowed it down to the fuel pump. I can jump it "cold" and it works just fine. As soon as I start the car and let it run for 5 min. +, it randomly doesn't work. If I let it cool for 30 min. + it always works again. I'm worried it will eventually leave me stranded. I guess I know what I'm doing this weekend.....
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