86 c4 fuel pressure issue

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Oct 7, 2019 | 01:29 PM

Mickey Repac

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5th Gear

Joined: Jun 2019

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From: Athens GA

86 c4 fuel pressure issue

Hello,
I have 86 C4 Corvette and have issue with fuel pressure. Pressure will stay at 25 psi and when i turn the car off goes to 10 psi. It take at least 20 turns to started cold and after that it runs but has no power.
Help please

Oct 7, 2019 | 02:01 PM

aklim

Team Owner

Joined: Jul 2004

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From: Hartford WI

Something might be leaking. Try crimping off the return line at the tank and have someone turn the key and see what happens.

Oct 7, 2019 | 02:34 PM

Mickey Repac

Thread Starter

5th Gear

Joined: Jun 2019

Posts: 5

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From: Athens GA

I have tried it with engine running and didn't see any difference. I have replaced fuel pump and filter.

Oct 7, 2019 | 02:35 PM

aklim

Team Owner

Joined: Jul 2004

Posts: 28,474

Likes: 3,291

From: Hartford WI

Quote:

Originally Posted by Mickey Repac

I have tried it with engine running and didn't see any difference. I have replaced fuel pump and filter.

So you turn the key to run and have the return line crimpped off? You can't get 40 plus psi?

Oct 7, 2019 | 03:19 PM

Tom400CFI

Team Owner

Joined: Aug 2004

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From: Park City Utah

X2^^^

Bad pump or a leak somewhere.

Oct 7, 2019 | 03:57 PM

Mickey Repac

Thread Starter

5th Gear

Joined: Jun 2019

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From: Athens GA

I have replaced 2 pumps in past month, i did buy one of the cheaper ones. I did take pulsator out, You think that would make it not build pressure?

Oct 7, 2019 | 04:06 PM

aklim

Team Owner

Joined: Jul 2004

Posts: 28,474

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From: Hartford WI

Quote:

Originally Posted by Mickey Repac

I have replaced 2 pumps in past month, i did buy one of the cheaper ones. I did take pulsator out, You think that would make it not build pressure?

I doubt it. Are you sure it is not building pressure but the regulator is letting it out?

Oct 7, 2019 | 08:18 PM

383vett

Race Director

Joined: Apr 2003

Posts: 17,700

Likes: 1,667

From: moraga ca

Sounds like the regulator is bad. If you have gone through 2 fuel pumps and still have the same problem not building up pressure, change the regulator.

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Oct 7, 2019 | 09:35 PM

aklim

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Joined: Jul 2004

Posts: 28,474

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From: Hartford WI

Have you tried crimping off the return line to the tank to see if it builds up pressure to 42 psi?

Oct 11, 2019 | 11:41 AM

#10

Mickey Repac

Thread Starter

5th Gear

Joined: Jun 2019

Posts: 5

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From: Athens GA

I have tried pinching return line and pressure stays the same. I have tried new pump and i am still getting 25psi. I am thinking that the gage is not reading properly.