Hot starting issues
Thread Starter
3rd Gear
Joined: May 2025
Posts: 3
Likes: 0
Hot starting issues
Hi all, I’m after some help with my 89 C4. I have an intermittent issue where the engine won’t start when at normal running temperature. I have fuel pressure and spark. I have also installed a VATS bypass to ensure that isn’t the issue.
Burning Brakes
Joined: Aug 2008
Posts: 823
Likes: 215
From: Tampa, FL
What if any sounds is it making? What happens when you crank it... does it crank normally but just doesn't start? If so... then it's not the starter. Sometimes when starters get too hot, as they age, the solenoid isn't able to engage until it cools off more. They sell a starter shield for that to prevent heat soak.
But if it cranks normally, but just doesn't catch, it could be the ignition control module. When you say you have spark, are you verifying in fact that you are actually getting spark at the spark plugs? Sometimes when ICMs are about to fail... they usually stop working when they're really hot.
Just a couple of things... but need more info to help determine...
Melting Slicks
Joined: Oct 2003
Posts: 2,141
Likes: 804
From: Chapel Hill NC
2025 c3 ('68-'73) of the Year Finalist - Unmodified
2025 C4 of the Year Finalist - Unmodified
2025 C8 Stingray of the Year Finalist - Unmodified
Id check the battery and its connections, the starter connections, and grounds.
Drifting
Joined: Jul 2022
Posts: 1,805
Likes: 365
From: Central Florida
I assume you mean the starter works fine but the engine won't fire. Fuel injectors most likely. Test them, if you don't know how there are plenty of videos. Test the impedance (ohms), test the operation (hear them click, open and close), then test for flow when hot. Sometimes bad injectors can be stubborn, when the engine is warm it will start but take a while. Use starting fluid to verify it is a fuel issue by pulling the PCV hose and squirting it into the intake manifold.
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Last edited by Vets-Vet; May 8, 2025 at 08:56 AM.
Thread Starter
3rd Gear
Joined: May 2025
Posts: 3
Likes: 0
Thanks.
Thank you guys. Definitely not a cranking issue, the engine turns over without any issues at all.
I have spark at the end of all high tension plug leads so no issue there either.
The YouTube video was exactly what’s happening with mine. I will test the injectors and then ignition control module if required.
Do you have any recommendations for replacement injectors?
thanks again for your help.
I have spark at the end of all high tension plug leads so no issue there either.
The YouTube video was exactly what’s happening with mine. I will test the injectors and then ignition control module if required.
Do you have any recommendations for replacement injectors?
thanks again for your help.
Drifting
Joined: Jul 2022
Posts: 1,805
Likes: 365
From: Central Florida
Fuel Injector Connection LLC This is the company most reccomended here at CF. I did not go with them and regret it.
http://www.fuelinjectorconnection.com
I went with a company in New Jersey and regret it to this day. I also wish I went with stock instead of Bosch III's. If I had to do it again, I would buy the Delphi OEM 22lb replacements from FuelInjectorConnection FOR MY 87. Are you looking for all out performance or just a good running car ? My car runs a little rough to this day using Bosch III's. Some claim they are running a little lean from Bosch III's. Others like them. Are you willing to re-tune the memcal if neccassary or do you just want your vette running as it should? I do not have the Delphi's and parts quality changes quickly in todays world.
Do not take my word for it. Do your own research.
Also, in that video most of the injectors ohmed out good, so just know that test is a simple one and not always conclusive.
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http://www.fuelinjectorconnection.com
I went with a company in New Jersey and regret it to this day. I also wish I went with stock instead of Bosch III's. If I had to do it again, I would buy the Delphi OEM 22lb replacements from FuelInjectorConnection FOR MY 87. Are you looking for all out performance or just a good running car ? My car runs a little rough to this day using Bosch III's. Some claim they are running a little lean from Bosch III's. Others like them. Are you willing to re-tune the memcal if neccassary or do you just want your vette running as it should? I do not have the Delphi's and parts quality changes quickly in todays world.
Do not take my word for it. Do your own research.
Also, in that video most of the injectors ohmed out good, so just know that test is a simple one and not always conclusive.
.
.
Thread Starter
3rd Gear
Joined: May 2025
Posts: 3
Likes: 0
Fuel Injector Connection LLC This is the company most reccomended here at CF. I did not go with them and regret it.
http://www.fuelinjectorconnection.com
I went with a company in New Jersey and regret it to this day. I also wish I went with stock instead of Bosch III's. If I had to do it again, I would buy the Delphi OEM 22lb replacements from FuelInjectorConnection FOR MY 87. Are you looking for all out performance or just a good running car ? My car runs a little rough to this day using Bosch III's. Some claim they are running a little lean from Bosch III's. Others like them. Are you willing to re-tune the memcal if neccassary or do you just want your vette running as it should? I do not have the Delphi's and parts quality changes quickly in todays world.
Do not take my word for it. Do your own research.
Also, in that video most of the injectors ohmed out good, so just know that test is a simple one and not always conclusive.
.
.
http://www.fuelinjectorconnection.com
I went with a company in New Jersey and regret it to this day. I also wish I went with stock instead of Bosch III's. If I had to do it again, I would buy the Delphi OEM 22lb replacements from FuelInjectorConnection FOR MY 87. Are you looking for all out performance or just a good running car ? My car runs a little rough to this day using Bosch III's. Some claim they are running a little lean from Bosch III's. Others like them. Are you willing to re-tune the memcal if neccassary or do you just want your vette running as it should? I do not have the Delphi's and parts quality changes quickly in todays world.
Do not take my word for it. Do your own research.
Also, in that video most of the injectors ohmed out good, so just know that test is a simple one and not always conclusive.
.
.
Being in Australia and the car converted to right hand drive, not all the components in the US will fit so I need to careful of what I buy.
Cruising
Joined: Dec 2008
Posts: 13
Likes: 4
From: Vegas
I had the same hot start issue and replaced the injectors in my 1988 L98 with the 22lb Bosch III. If you do this it will run lean at 40 psi (stock) fuel pressure. Change the fuel pressure regulator to an adjustable type and boost the pressure to about 50 psi or so, where it will cold start and run normally at colder (below 75F) temps. I bought my car in new in 1988 and have not noticed any change in idle or performance with the Bosch injectors vs. the original.
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