Need thoughts and ideas for troubleshooting
Thread Starter
Burning Brakes
Joined: Nov 2008
Posts: 995
Likes: 1
From: Naples Campania
Need thoughts and ideas for troubleshooting
Okay, this is a common problem with the L98s apparantly and I have done research, I'm just checking to see if anyone else has some tips or maybe a few other options.
I haven't been here a lot at all lately, so I'll refresh you on the car.
1991 Corvette L98
700-R4 Trans (gutted and rebuilt thanks to Redline)
ZZ4 Block bored to 355
Edelbrock RPM heads
Stock intake (
I know. I have another intake system that I will eventually siamese)
26 lb fuel injectors (slightly too big, cause slight rich condition)
No codes
Starting with the story. I have a thread here, but it didn't really go anywhere. I was taking a hard corner (testing out new sway bar to replace the tiny stock one they use for the "soft" suspension. Worked like a dream by the way) and suddenly fuel cut out. After 2 weeks of troubleshooting, I found out I was using the wrong schematics and wasn't finding the correct "FP" fuse. It was blown, so I replaced it. I had already replaced the fuel pump because it was bad and probably caused the fuse to blow in the first place. So, new fuse, new pump. I tested the fuel pump relay via the ECM connectors and tested all the way back to the sending unit connector. Tested good. 12V tested good as well both during the priming stage and during cranking.
Problem.
Car turns over, fuel is good, but sputters and dosesn't run for more than a couple of seconds. Loosened the distro and tried to time it. Can't get it to start. It is now bolted down in the best position I could find. As I said before, I am NOT the first person to have this problem. Below is a list of things I will check tomorrow (don't have immediate access to the car right now).
IAC - unplug, try to start (IAC ignore). Remove, clean and beat.
ICM - (just to confirm, on top of distro for L98?) 1 y/o distro, should be okay. I'll test the entire distro just in case.
Test fuel pressure.
Confirm injector pulse.
Confirm spark on cables and plugs.
That's what I am going to test in the order I'm going to test. I have been staring at the project for too long and a need a few extra brains to help me out. Anyother ideas? I'm betting on the IAC. I know it is a high-fail item and as far as I know it's origional to the motor.
I haven't been here a lot at all lately, so I'll refresh you on the car.
1991 Corvette L98
700-R4 Trans (gutted and rebuilt thanks to Redline)
ZZ4 Block bored to 355
Edelbrock RPM heads
Stock intake (
I know. I have another intake system that I will eventually siamese)26 lb fuel injectors (slightly too big, cause slight rich condition)
No codes
Starting with the story. I have a thread here, but it didn't really go anywhere. I was taking a hard corner (testing out new sway bar to replace the tiny stock one they use for the "soft" suspension. Worked like a dream by the way) and suddenly fuel cut out. After 2 weeks of troubleshooting, I found out I was using the wrong schematics and wasn't finding the correct "FP" fuse. It was blown, so I replaced it. I had already replaced the fuel pump because it was bad and probably caused the fuse to blow in the first place. So, new fuse, new pump. I tested the fuel pump relay via the ECM connectors and tested all the way back to the sending unit connector. Tested good. 12V tested good as well both during the priming stage and during cranking.
Problem.
Car turns over, fuel is good, but sputters and dosesn't run for more than a couple of seconds. Loosened the distro and tried to time it. Can't get it to start. It is now bolted down in the best position I could find. As I said before, I am NOT the first person to have this problem. Below is a list of things I will check tomorrow (don't have immediate access to the car right now).
IAC - unplug, try to start (IAC ignore). Remove, clean and beat.
ICM - (just to confirm, on top of distro for L98?) 1 y/o distro, should be okay. I'll test the entire distro just in case.
Test fuel pressure.
Confirm injector pulse.
Confirm spark on cables and plugs.
That's what I am going to test in the order I'm going to test. I have been staring at the project for too long and a need a few extra brains to help me out. Anyother ideas? I'm betting on the IAC. I know it is a high-fail item and as far as I know it's origional to the motor.
Burning Brakes
Joined: Mar 2010
Posts: 1,094
Likes: 68
From: Providence RI
The ignition coil is on top of the distributor. The icm is down under the rotor. Fuel pressure test will give you a lot of information. If it primes to 40ish and holds around 38 with key on engine off, youre good. If it maintains 40ish while running/sputtering, youre good there too.
When you tried to time it, did you unplug the EST connector near the ECU/brake booster? Single wire with a weatherpack connector.
Mike
When you tried to time it, did you unplug the EST connector near the ECU/brake booster? Single wire with a weatherpack connector.
Mike
