Cold Start problems
Thread Starter
Navigator
Joined: May 2025
Posts: 9
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Cold Start problems
Hello all. My routine newbie question.
1990 L98 convertible.
it starts up fine when it’s warmed up. Cold starting is a struggle. Sometimes it’ll take multiple attempts. Additionally, the oil pressure is high (roughly 70psi) after these near failed attempts on the cold start.
I’ve heard it could be a fuel pump relay, coolant temp sensor, or some ecm thing. Anyone have any experience with addressing this? Thanks for any help!
1990 L98 convertible.
it starts up fine when it’s warmed up. Cold starting is a struggle. Sometimes it’ll take multiple attempts. Additionally, the oil pressure is high (roughly 70psi) after these near failed attempts on the cold start.
I’ve heard it could be a fuel pump relay, coolant temp sensor, or some ecm thing. Anyone have any experience with addressing this? Thanks for any help!
Thread Starter
Navigator
Joined: May 2025
Posts: 9
Likes: 1
I also just checked the oil and saw that while cold, the oil level is pretty high above operating range which might be causing the starting issue. My assumption is that when oil heats, it retracts and therefore the pressure would decrease which is why the engine would start up fine while warm.
Melting Slicks
Joined: Oct 2003
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From: Chapel Hill NC
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Im not certain regarding your assumptions on the oil level, however you should drain the oil to the proper level.
Does the car throw any codes? Hard cold start man be a faulty temp sensor.
Does the car throw any codes? Hard cold start man be a faulty temp sensor.
Thread Starter
Navigator
Joined: May 2025
Posts: 9
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Which temp sensor would this be/where can I find it? The only one I am tracking is the coolant temp sensor. Is that possibly what I need to replace?
Team Owner
Joined: Jan 2003
Posts: 20,254
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From: Summerland B.C. Canada
It could cause hard start even without setting code, but you need a scan tool to see what the ECM sees.
It is a cheap part, so swapping it won’t hurt the bank.
Last edited by AGENT 86; Jun 9, 2025 at 07:02 PM.
Thread Starter
Navigator
Joined: May 2025
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will post the final results here later. Thank you
Thread Starter
Navigator
Joined: May 2025
Posts: 9
Likes: 1
Follow Up
Still having cold start issues. I have recently replaced: fuel pressure regulator, fuel injectors, coolant temp sensor, MAT sensor, every fuse, and the fuel filter.
The only things I can think of may be cooling system-related which would be a thermostat (would explain its high operating temp) and maybe spark plugs/wires? I cannot seem to think of what else may cause a harsh/long cold start.
The only things I can think of may be cooling system-related which would be a thermostat (would explain its high operating temp) and maybe spark plugs/wires? I cannot seem to think of what else may cause a harsh/long cold start.
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Drifting
Joined: Nov 2018
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From: Mays Landing, NJ
Normally if the CTS (front of block) is bad it will start fine but you'll see an issue when it warms because it doesn't lean the fuel for closed loop. I don't see the CTS as being your problem.
Melting Slicks
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I've been having this issue on my '90 lately.
CTS and pigtail were replaced.
Could be fuel bleed-off after sitting for a while.
I know that I need to replace the o-rings on my fuel lines where it runs into the fuel rail. May not be helping matters.
I ordered a new ignition control module, so after I receive and install that I'l let you know if it resolved.
CTS and pigtail were replaced.
Could be fuel bleed-off after sitting for a while.
I know that I need to replace the o-rings on my fuel lines where it runs into the fuel rail. May not be helping matters.
I ordered a new ignition control module, so after I receive and install that I'l let you know if it resolved.