losing fuel pressure
Thread Starter
Advanced
Joined: Feb 2012
Posts: 71
Likes: 14
From: Redding California
losing fuel pressure
I have a 1994 Corvette LT1...I was driving the other day and out of the blue the car died... waited about 1-2 minutes and it started right up. This has happened several times so I put a fuel pressure gauge on so I could see it in the window. I have 42-44 psi with key on and after start between 34-38 psi. So I assume the fuel pressure regulator is lowering the pressure. The car drives fine for between 5-10 minutes and will lose fuel pressure. You can always count on it restarting after the 1-2 minutes. I have changed fuel pump and strainer and the fuel filter. I have changed the oil pressure sensor even tho the gauge says I have pressure. I have run the car with and without the fuel cap...no change.
My question is what's causing the loss of pressure and what's with the wait time to restart?
My question is what's causing the loss of pressure and what's with the wait time to restart?
Last edited by Handi; Feb 12, 2012 at 08:20 PM.
Thread Starter
Advanced
Joined: Feb 2012
Posts: 71
Likes: 14
From: Redding California
Yes as in ZERO pressure....I can watch the pressure gauge that I have installed and when the car dies the gauge psi drops to zero....wait between 1-2 minutes and I get my 42-44 psi back with the key on...then starts like there was never a problem....but the cycle continues....Something is shutting the pump off...and the only thing left that hasnt been changed is the pump relay....but then why is there the time delay for the pump to come back online??
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
Replace the fuel pump relay and check the condition of the harness connectors at the F/P especially where the wires attach to the connectors. Loose wire/connector or bad relay.
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
Did you check for corrosion on the two contacts where the FP connects electrically to the holder? If blackened they may be the problem and cleaning them may eliminate the issue.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
5 MOST and 5 LEAST Popular Corvette Model Years in History!
Joe Kucinski
2027 Corvette Buyer's Guide: Everything You Need to Know!
Joe Kucinski
10 Things C8 Corvette Owners Hate (But Won't Tell You)
Joe Kucinski
10 Best Corvettes Coming to Barrett-Jackson Palm Beach 2026!
Brett Foote
Every Corvette Grand Sport Explained! (C2, C4, C6, C7, & C8)
Joe Kucinski
Race Director
Joined: Oct 2000
Posts: 14,060
Likes: 1,165
From: N. Alabama
I have to wonder if maybe a stuck injector may cause this, too? Not sure what else a bad injector may cause, though. Without starting engine, the pump will run a couple of seconds and shut off. Does the pressure gauge maintain? If not, regulator needs rebuilt or replaced but may not be the whole problem.
Safety Car
Joined: Sep 2010
Posts: 3,752
Likes: 190
From: Indiana PA
Thread Starter
Advanced
Joined: Feb 2012
Posts: 71
Likes: 14
From: Redding California
It's fixed !!
My problem just returned. CFI-EFI clued me on how the fuel system actually works...THX. I want to replace the fuel pump relay but the manual says it is under the passenger side dash. The only relays I find are in a cluster inside a box that do not resemble the fsm picture and are not marked. Anyone know if this is the right location and which particular relay is for the fuel pump?
Last edited by Handi; Apr 3, 2012 at 06:44 PM.
