LT1 Fuel pressure question.
Thread Starter
Racer
Joined: Jun 2000
Posts: 469
Likes: 0
From: Norfolk VA
LT1 Fuel pressure question.
I have been looking at alot of things trying to figure out a high end miss, I have and came across another question. In checking my injectors I notice that when I turn on the key, the pump runs and brings F/P to 46 psi. As soon as the pump shuts off the F/P drops to 0 in less than 10 seconds! The first thing I thought was injectors. I swapped in the stock injectors, same thing. Then LPDesroche brought some new 36#er's over we swapped them in same thing. Is it supposted to do this? I dont think so. How about F/P regulator? Could it be bad?
TIA,
RJ
TIA,
RJ
Le Mans Master
Joined: Mar 1999
Posts: 9,663
Likes: 1,680
From: Fort Worth Texas
2024 Corvette of the Year Finalist - Unmodified
2023 C8 of the Year Winner - Unmodified
2020 Corvette of the Year Finalist (stock)
2019 C7 of Year Winner (stock)
Former Moderator
Cruise-In I-II-III Veteran
Re: LT1 Fuel pressure question. (HJV11)
It's either the regulator or the pump allowing the fuel to return. They both need to hold the pressure. You can check the pump by squeezing the return line and trying crimp it at the tank, and see if the pressure stays or bleeds off. I've never been able to do that, but others have told me they can pinch it off back there!
It needs to hold pressure though, that's not normal.
It needs to hold pressure though, that's not normal.
Team Owner
Joined: Apr 2001
Posts: 22,267
Likes: 3
From: Dallas TX
Re: LT1 Fuel pressure question. (Marcho Polo)
OOhhh wee... if you ask me... that's not the injectors leaking, i'd say it's your fuel pump, etc... I didn't think the injectors could lose pressure that fast... not a lot of gas comes out of there.. and for it to be gone in under 10 sec sounds odd. I MAY be wrong though.. your injectors could be seriously messed up. I would check the pump.. its probalby allowing the fuel to flow back out.
Melting Slicks
Joined: Apr 2000
Posts: 2,793
Likes: 46
From: Elizabeth City, NC
Re: LT1 Fuel pressure question. (Glock'94)
We know its not the injectors, we tried 3 different sets. And one of them was a brand new set of 36#'s that I have. I know they are good. They were just flow tested. More than likely it's the regulator its the original one, pump isn't that old. Either one is easy though luckily. Every day is a new adventure.... :crazy:
Le Mans Master
Joined: Oct 2000
Posts: 6,362
Likes: 30
From: Oak Harbor WA
Re: LT1 Fuel pressure question. (LPDesRoche)
My Helms manual states it is either the fuel pump check ball, the pressure regulator, or leaking fuel pulse dampener.
The return line is used only for excess fuel that isn't used by the injectors.
Take a look at Chart A-7 in book 2.
The return line is used only for excess fuel that isn't used by the injectors.
Take a look at Chart A-7 in book 2.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
Pro
Joined: Dec 2001
Posts: 715
Likes: 0
From: NYC NY
Re: LT1 Fuel pressure question. (HJV11)
Mine did the exact same thing. Fine at startup up then pressure droped down to nearly nothing. Found out what it was three weeks later and 150 miles from home. Bad fuel pump. Not hard to fix. Thankfully I had a spare at home and didn't have to have her towed.
