89 Won't Run
Thread Starter
4th Gear
Joined: Jun 2006
Posts: 4
Likes: 0
From: Rio Rancho NM
89 Won't Run
Hello: My 89 Corvette (with only 27k miles on it) developed this issue:
On a cold start, it will attempt to run for approx 20 secs. The engine hunts between 500-700rpm and will stall out after about half a min.
When hitting the accelerator, it will stall immediately. Once engine is warm, just cranks over, no run at all. Vette was fine and then all of the sudden has this issue. Everything is stock. No mods. I checked / replaced the following: Fuel pressure @ shrader is 43psi. Replaced the ignition control module and Coil. No Change. Also tried a new (re manufactured) ECM with no change. I did ohm out the injectors and found one to be way off at about .01; with the others all at .16. Would one bad injector cause this issue?
Another data point: If you hit it with ether, it runs fine for that 2 secs.
Any ideas?
Thanks.
Keith
On a cold start, it will attempt to run for approx 20 secs. The engine hunts between 500-700rpm and will stall out after about half a min.
When hitting the accelerator, it will stall immediately. Once engine is warm, just cranks over, no run at all. Vette was fine and then all of the sudden has this issue. Everything is stock. No mods. I checked / replaced the following: Fuel pressure @ shrader is 43psi. Replaced the ignition control module and Coil. No Change. Also tried a new (re manufactured) ECM with no change. I did ohm out the injectors and found one to be way off at about .01; with the others all at .16. Would one bad injector cause this issue?
Another data point: If you hit it with ether, it runs fine for that 2 secs.
Any ideas?
Thanks.
Keith
Pro
Joined: Jun 2006
Posts: 508
Likes: 1
From: Miami Florida
I also have an 89 and had one injector take a dump while driving, no less. The car stalled and would not start at all. I managed to get it to the curb and no amount of trying or cussing in two languages (maybe three if you count spanish) would make that car run. I would suggest replacing the bad injector and see if that solves the issue.
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
The starting fluid running tells you that you have a fuel problem. Fuel pressure should hold up for at least 1/2 hour with the ignition off. Rapid pressure decay is a sign of a leaky injector/s or a defective fuel pressure regulator check valve. Test an injector on each cylinder bank with a noid light (available at parts stores). The light should pulse during cranking. You can make your own light with an LED (light emitting diode) in series with a 680 ohm resistor. You connect the light on an unplugged injector socket. A homemade noid light has to be connected with the correct polarity, you can try it both ways.
Measuring the d.c. resistance of injector coils will only find gross coil failures. A coil with a turn to adjacent turn short cannot be found with an ohmeter and it will prevent proper injection because injectors receive pulses from the ECM. The best electrical test is done with an impedance bridge which measures the inductance and coil Q. I found a defective injector once on my 87, it had 1/2 the inductance and 1/2 the Q of the other injectors. Its d.c. resistance was identical to the other injectors.
Measuring the d.c. resistance of injector coils will only find gross coil failures. A coil with a turn to adjacent turn short cannot be found with an ohmeter and it will prevent proper injection because injectors receive pulses from the ECM. The best electrical test is done with an impedance bridge which measures the inductance and coil Q. I found a defective injector once on my 87, it had 1/2 the inductance and 1/2 the Q of the other injectors. Its d.c. resistance was identical to the other injectors.
Instructor
Joined: Aug 2009
Posts: 146
Likes: 0
From: Broadway Virginia
If you do decide that an injector is at fault and causing your problems, replace all of them as a set and not just the one. Also, a new fuel filter in addition to whatever else you try never hurts.
Le Mans Master
Joined: Sep 2006
Posts: 6,050
Likes: 147
From: Phoenix AZ
2021 C4 of the Year - Modified Finalist
At 27,000 miles and all this time I would expect some problems to occur.
fuel:
check for water in the tank
check for fuel filter getting plugged up
check for bad injectors
check for bad pulsator
Check fuel pressure
check for small leaks around fuel rail o rings
manifold:
check for bad vacuum hoses
check for deteriorated pcv valve hoses and elbows
check for bad vacuum check valve behind distributor
ignition:
check grounds
check for old leaking spark plug wires
check for power wire and tach secure in cap connector
inspect spark plugs for firing anamalies
fuel:
check for water in the tank
check for fuel filter getting plugged up
check for bad injectors
check for bad pulsator
Check fuel pressure
check for small leaks around fuel rail o rings
manifold:
check for bad vacuum hoses
check for deteriorated pcv valve hoses and elbows
check for bad vacuum check valve behind distributor
ignition:
check grounds
check for old leaking spark plug wires
check for power wire and tach secure in cap connector
inspect spark plugs for firing anamalies
Last edited by coupeguy2001; Sep 12, 2010 at 12:00 PM.
Thread Starter
4th Gear
Joined: Jun 2006
Posts: 4
Likes: 0
From: Rio Rancho NM
Update: Placed in a noid light on the one connector for that injector which didn't ohm like the others.. Sure enough the car started and ran.. Guess that one injector causes enough havoc the car cannot run.
Thanks!
Thanks!
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
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