Hard Starting 1990 L98

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Aug 6, 2008 | 06:10 PM

Kubs

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Le Mans Master

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From: Akron Ohio

2025 Corvette of the Year Finalist - Modified

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St. Jude Donor '09-'10-'11

Hard Starting 1990 L98

Here is the problem. When the car is hot, or has been sitting for some time it cranks for a while ( maybe 10 sec.) before starting. Long story short, this was happening every time I tried to start the car and I smelled fuel. I just replaced the injectors, thinking that was my problem, with Ford Racing Red Top 30 lb/hr ones and had the computer tuned. This greatly improved my gas milage, it doesnt take as long to start now, and I no longer smell fuel. However it still cranks for some time before starting. I hooked a fuel pressure gauge up to it not too sure what the proper procedure was for checking fuel pressure. I turned the key on, heard the pump come on, but the needle didnt move. I started the car and the gauge read a steady 38 psi. When I shut the car off I turned the key back to the on position and the gauge jumped to 44 psi and slowly dropped to 0. Do I have some sort of internal fuel leak or am I checking the pressure wrong? It has had a tune up around 1000 miles ago. Is this even a fuel issue??

Thanks

Aug 6, 2008 | 07:25 PM

65Z01

Team Owner

Joined: Dec 2000

Posts: 90,675

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From: SE NY

Cruise-In II Veteran

Quote:

When I shut the car off I turned the key back to the on position and the gauge jumped to 44 psi and slowly dropped to 0.

It sounds like you have a leak somewhere:
-injectors
-FPR
-FP
-lines

After you turn the key On the FP should run for ~2sec charging the line to around 44psi and this pressure should hold for at least a few minutes.

Aug 6, 2008 | 07:42 PM

cwyates4

Melting Slicks

Joined: Jan 2008

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From: Jasper Texas

Follow this guide and you will find your problem:

http://members.shaw.ca/corvette86/Fu...mDiagnosis.pdf

Aug 7, 2008 | 07:07 AM

Kubs

Thread Starter

Le Mans Master

Joined: Oct 2007

Posts: 9,687

Likes: 3,440

From: Akron Ohio

2025 Corvette of the Year Finalist - Modified

2024 C5 of the Year Winner - Modified

2023 C5 of the Year Finalist - Modified

2022 C5 of the Year Finalist - Modified

St. Jude Donor '09-'10-'11

Quote:

Originally Posted by 65Z01

When I turn the key on the gauge does not move until I crank the engine over...

I just replaced the injectors thinking that was the roblem but it still does it.

Aug 7, 2008 | 07:12 AM

Kubs

Thread Starter

Le Mans Master

Joined: Oct 2007

Posts: 9,687

Likes: 3,440

From: Akron Ohio

2025 Corvette of the Year Finalist - Modified

2024 C5 of the Year Winner - Modified

2023 C5 of the Year Finalist - Modified

2022 C5 of the Year Finalist - Modified

St. Jude Donor '09-'10-'11

Quote:

Originally Posted by cwyates4

Follow this guide and you will find your problem:

http://members.shaw.ca/corvette86/Fu...mDiagnosis.pdf

Thanks! That looks great. I will try that.

Aug 7, 2008 | 11:04 AM

rick lambert

Le Mans Master

Joined: Oct 2003

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From: seattle WA

Could be a few things, but I'm betting on the fuel pressure regulator, pull the vacumn line off it and see if it's wet (gas) if it is then you know what the problem is. I only think this because of the smell, if it were the fuel pump pulsator or check valve I doubt you'd be able to smell it. BTW, how old is the pump and filter?

Aug 7, 2008 | 01:18 PM

wro87

Burning Brakes

Joined: May 2006

Posts: 857

Likes: 1

From: Morrisonville Illinios

ALso look around the FP gauge. We found that ours was leaking and it would smell when we shut it off took as a while until we could see it drip. When we tighten it up it started to pour/spray all over (lucky no fire), Found that the tupe from the rail to the gauge was just brass and it cracked. bought the repalcement fittings from Summit a real nice ANR fitting with the right connectors and an extra gauge. Good luck.

Good luck wro87

Aug 7, 2008 | 04:03 PM

Kubs

Thread Starter

Le Mans Master

Joined: Oct 2007

Posts: 9,687

Likes: 3,440

From: Akron Ohio

2025 Corvette of the Year Finalist - Modified

2024 C5 of the Year Winner - Modified

2023 C5 of the Year Finalist - Modified

2022 C5 of the Year Finalist - Modified

St. Jude Donor '09-'10-'11

Quote:

Originally Posted by rick lambert

I dont know how old the pump/filter are. I have new filter I was planning on putting on but I think if it were a clogged filter the performance would be effected and its not. I bought the car with a salvage title from the junk yard after it was rear ended. The tank and pump were replaced but the parts came from another car so both are not new. So to check the regulator I just undo the vacuum line where it connects to the regulator and if its wet thats the problem??

As far as the gauge, its not a permanent one, I screw it on the fitting and lay it on the windshield while I play with the key. That wasnt leaking because there was no gas around it after checking the pressure.