1990 will not start when hot
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From: Mechanicsburg PA
1990 will not start when hot
We have a 1990 with a L98 in it, and the damn thing will not start when hot. We've taken it to a corvette dealer, and first they said it was the fuel pump, then they said it was the computer(pcm, ecm, whatever you want to call it nowadays). They replaced both, and the car still will not start when hot.
Here is what happens: I took the car to work one afternoon, and returned home around 3pm. Then I went to start the car up at 5pm, and the starter would just crank and crank, but the engine would not catch and fire up. So I left it be, and came back around 9:30pm, and the car started right up. I took it for a drive, and parked it. Then I tried to start it again an hour later, and it would do the same thing and just crank the starter but not fire. It sat overnight, and of course, fired right up in the morning when it was cold.
Does anyone have any ideas of what this could be? It has to of happened to someone else.....Any help would be appreciated. Thanks
Here is what happens: I took the car to work one afternoon, and returned home around 3pm. Then I went to start the car up at 5pm, and the starter would just crank and crank, but the engine would not catch and fire up. So I left it be, and came back around 9:30pm, and the car started right up. I took it for a drive, and parked it. Then I tried to start it again an hour later, and it would do the same thing and just crank the starter but not fire. It sat overnight, and of course, fired right up in the morning when it was cold.
Does anyone have any ideas of what this could be? It has to of happened to someone else.....Any help would be appreciated. Thanks
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Re: 1990 will not start when hot (psuvette)
Might be a leaky fuel injector and your car won't start because it is flooded when you go to start it. Have you tried the quick test outlined in tech tips (something like before attempting a hot start, hold the gas pedal down for 5-10 seconds and see if it will start normally. You're not actually giving it more gas, but allowing the built-up, leaked gas/vapor to clear a bit).
If it is leaky injectors and the dealer didn't check, I personally wouldn't go back to them.
Already been posted, but Rich at Cruzin Performance (http://www.cruzinperformance.com/) is the man for injector cleaning and flow tests and its only $10/injector plus shipping.
If it is leaky injectors and the dealer didn't check, I personally wouldn't go back to them.
Already been posted, but Rich at Cruzin Performance (http://www.cruzinperformance.com/) is the man for injector cleaning and flow tests and its only $10/injector plus shipping.
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From: Mechanicsburg PA
Re: 1990 will not start when hot (Dutch W.)
Might be a leaky fuel injector and your car won't start because it is flooded when you go to start it. Have you tried the quick test outlined in tech tips (something like before attempting a hot start, hold the gas pedal down for 5-10 seconds and see if it will start normally. You're not actually giving it more gas, but allowing the built-up, leaked gas/vapor to clear a bit).
If it is leaky injectors and the dealer didn't check, I personally wouldn't go back to them.
Already been posted, but Rich at Cruzin Performance (http://www.cruzinperformance.com/) is the man for injector cleaning and flow tests and its only $10/injector plus shipping.
If it is leaky injectors and the dealer didn't check, I personally wouldn't go back to them.
Already been posted, but Rich at Cruzin Performance (http://www.cruzinperformance.com/) is the man for injector cleaning and flow tests and its only $10/injector plus shipping.
Drifting
Joined: Mar 1999
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From: Norcross GA
Re: 1990 will not start when hot (psuvette)
Basic stuff,....
Does it spark when no-start?
What is the fuel pressure @ no-start?
When you pull the plug after a couple no-start attempts, what do you see?
Pull many,... what do you see?
Does it spark when no-start?
What is the fuel pressure @ no-start?
When you pull the plug after a couple no-start attempts, what do you see?
Pull many,... what do you see?
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From: Mechanicsburg PA
Re: 1990 will not start when hot (ZylaRace)
to tell you the truth, its at the dealer right now. to quote the mechanic, 'we're stumped'. I have no clue what they've done or haven't done to troubleshoot.
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Re: 1990 will not start when hot (psuvette)
Gee...
I had the exact same problem with my 1990 with about 65000 miles on it. The no start after being warmed up for 1/2 hour or so was so reproducible, I could make it fail on demand.
The problem in my case was simple. I had 3 failed fuel injectors. The Multec Rochester Injectors on the 1990 are pure garbage and have some of the highest pattern failures in the industry. They short out real easy and this can easily be measured by the mechanic to check the resistance hot and cold.
The GM engineering team that designed these injectors should all be castrated. I spent over $1400.00 Canadian in injectors alone to fix the problem. My mechanic replaced all my injectors with Echlins. The car runs like an animal and will start immediately after being driven any distance. Problem solved.
It idles like a dream, and with no precats on the car, my Vette goes like hell.
Replacing the injectors with aftermarket(no GM crap for me in that area).
Good luck,
:D
I had the exact same problem with my 1990 with about 65000 miles on it. The no start after being warmed up for 1/2 hour or so was so reproducible, I could make it fail on demand.
The problem in my case was simple. I had 3 failed fuel injectors. The Multec Rochester Injectors on the 1990 are pure garbage and have some of the highest pattern failures in the industry. They short out real easy and this can easily be measured by the mechanic to check the resistance hot and cold.
The GM engineering team that designed these injectors should all be castrated. I spent over $1400.00 Canadian in injectors alone to fix the problem. My mechanic replaced all my injectors with Echlins. The car runs like an animal and will start immediately after being driven any distance. Problem solved.
It idles like a dream, and with no precats on the car, my Vette goes like hell.
Replacing the injectors with aftermarket(no GM crap for me in that area).
Good luck,
:D
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From: Mechanicsburg PA
Re: 1990 will not start when hot (Black Beast)
hmm....well, if your car won't start after being on for about a half hour(sounds about right here....) and you had some screwed injectors.....its worth a shot. if it is the problem, then i beat ya to it, because ours only has 52,000 miles on it :) tomorrow ill stop by the garage and suggest that its the injectors shorting out when they get hot. If indeed that is the problem, perhaps I'll let them know that I'll find my own injectors to install :)
Thanks - I hope you nailed this one on the head, because the dealer sure doesn't know what the hell is going on....especially for a chevy/vette dealer...
Thanks - I hope you nailed this one on the head, because the dealer sure doesn't know what the hell is going on....especially for a chevy/vette dealer...
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Re: 1990 will not start when hot (psuvette)
Reason i asked if you smelled any fuel is that leaky injectors tend to have this problem.
I will bet money that you have some leaky or failed injectors.
I will bet money that you have some leaky or failed injectors.
Safety Car
Joined: Mar 2000
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From: Hillsboro OR
Re: 1990 will not start when hot (psuvette)
Diagnosing this goes back to basics..... Is it a fuel or spark problem.
The dealer mechanics should narrow it down to fuel or spark. If your getting spark when this happens, its the fuel. If no spark, then it could be the ignition module, coil etc. They should have a scope available to be able to see if the signals from the ecm are getting to the module.
This is a heat soak problem so anthing that can be affected by engine heat is the likely place to look. I would narrow it down to the spark or fuel and then check connections etc and work back from that.
The dealer mechanics should narrow it down to fuel or spark. If your getting spark when this happens, its the fuel. If no spark, then it could be the ignition module, coil etc. They should have a scope available to be able to see if the signals from the ecm are getting to the module.
This is a heat soak problem so anthing that can be affected by engine heat is the likely place to look. I would narrow it down to the spark or fuel and then check connections etc and work back from that.
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Joined: Apr 2001
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From: Mechanicsburg PA
Re: 1990 will not start when hot (Black Beast)
Gee...
I had the exact same problem with my 1990 with about 65000 miles on it. The no start after being warmed up for 1/2 hour or so was so reproducible, I could make it fail on demand.
The problem in my case was simple. I had 3 failed fuel injectors. The Multec Rochester Injectors on the 1990 are pure garbage and have some of the highest pattern failures in the industry. They short out real easy and this can easily be measured by the mechanic to check the resistance hot and cold.
The GM engineering team that designed these injectors should all be castrated. I spent over $1400.00 Canadian in injectors alone to fix the problem. My mechanic replaced all my injectors with Echlins. The car runs like an animal and will start immediately after being driven any distance. Problem solved.
It idles like a dream, and with no precats on the car, my Vette goes like hell.
Replacing the injectors with aftermarket(no GM crap for me in that area).
Good luck,
:D
I had the exact same problem with my 1990 with about 65000 miles on it. The no start after being warmed up for 1/2 hour or so was so reproducible, I could make it fail on demand.
The problem in my case was simple. I had 3 failed fuel injectors. The Multec Rochester Injectors on the 1990 are pure garbage and have some of the highest pattern failures in the industry. They short out real easy and this can easily be measured by the mechanic to check the resistance hot and cold.
The GM engineering team that designed these injectors should all be castrated. I spent over $1400.00 Canadian in injectors alone to fix the problem. My mechanic replaced all my injectors with Echlins. The car runs like an animal and will start immediately after being driven any distance. Problem solved.
It idles like a dream, and with no precats on the car, my Vette goes like hell.
Replacing the injectors with aftermarket(no GM crap for me in that area).
Good luck,
:D
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St. Jude Donor '07-'08-'09-'10-'11-'12-'13-'14-'15-'16-‘17, '22
Re: 1990 will not start when hot (psuvette)
I had a similar problem. Fuel pressure was good, as was the injector resistance. My problem was a little different in that if I got it started it sometimes cut out on me while driving and stalled - I could not restart it after this happened unless I waited at least 30 mins to let it cool down.
I replaced the ignition module and the problem went away.
[Modified by Red 90 L98 Coupe, 8:09 PM 7/10/2002]
I replaced the ignition module and the problem went away.
[Modified by Red 90 L98 Coupe, 8:09 PM 7/10/2002]
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From: Toronto ontario
Re: 1990 will not start when hot (Red 90 L98 Coupe)
I had the same problem with my 93. Wasnt no injector..... the Starter was the culprit. eventually it stopped workign entirely. Check it out, it may be the demon.
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From: Mechanicsburg PA
Re: 1990 will not start when hot (5abivt)
it can't be the starter. it's more like the guys post two up. the car has low fuel pressure, and will start when cold. then when it warms up, the car will die out. it then won't start after it gets warm. i thought the mechanic replaced the computer....but he may have meant the main computer. i'm not sure if these vettes have 2 or 3 modules or what. if thats the case, maybe he replaced the wrong one.
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St. Jude Donor '07-'08-'09-'10-'11-'12-'13-'14-'15-'16-‘17, '22
Re: 1990 will not start when hot (psuvette)
I didn't replace the engine computer.
I replaced the ignition module which is located on top of the distributor underneath the distributor cap. Remove the distributor cap, rotor and then the small metal retainer on the drivers side of the distributor that holds the ignition module down (black plastic module with plugs in either end of it). Remove the plugs from either side of the module and remove it.
Your mechanic should be able to replace the part inside of an hour.
Hope this helps.
[Modified by Red 90 L98 Coupe, 2:29 AM 7/11/2002]
I replaced the ignition module which is located on top of the distributor underneath the distributor cap. Remove the distributor cap, rotor and then the small metal retainer on the drivers side of the distributor that holds the ignition module down (black plastic module with plugs in either end of it). Remove the plugs from either side of the module and remove it.
Your mechanic should be able to replace the part inside of an hour.
Hope this helps.
[Modified by Red 90 L98 Coupe, 2:29 AM 7/11/2002]
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From: Mechanicsburg PA
Re: 1990 will not start when hot (Red 90 L98 Coupe)
I can visualize the procedure. I have one remaining question though. Would a failing ignition module cause low fuel pressure? Because that is one of the symptoms I've been told. I don't see how it would cause that.
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Re: 1990 will not start when hot (psuvette)
You are correct, no - the module will not cause low fuel pressure.
In my opinion, the low pressure MAY be the problem. However, it may be low but not low enough to cause the problem you mention.
I just thought I'd mention my experience as everyone seemed focused on the injector/fuel issue and that may not have been the problem.
If the fuel injector resistance checks out to be okay and the fuel pressure is constantly low I would check either the fuel filter next or try changing the ignition module to see if that works. Either would be quicker/easier than testing the fuel pump which could be another cause of low fuel pressure. Just my opinion as a non-mechanic who does his own Corvette work. :) HTH
In my opinion, the low pressure MAY be the problem. However, it may be low but not low enough to cause the problem you mention.
I just thought I'd mention my experience as everyone seemed focused on the injector/fuel issue and that may not have been the problem.
If the fuel injector resistance checks out to be okay and the fuel pressure is constantly low I would check either the fuel filter next or try changing the ignition module to see if that works. Either would be quicker/easier than testing the fuel pump which could be another cause of low fuel pressure. Just my opinion as a non-mechanic who does his own Corvette work. :) HTH
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From: Mechanicsburg PA
Re: 1990 will not start when hot (Red 90 L98 Coupe)
the thing is...what the hell could cause the car to start when cold....and then DIE after it gets hot? i believe from what the mechanic says, it just shuts off.
lets pretend the injectors are fine when they're cold, but short out when they get hot. the mechanic says that they tested fine though...but....wouldn't he have tested them when they were cold?
yea, i know, i'm reaching :sad:
lets pretend the injectors are fine when they're cold, but short out when they get hot. the mechanic says that they tested fine though...but....wouldn't he have tested them when they were cold?
yea, i know, i'm reaching :sad: