Fuel pressure issue
Thread Starter
Teching In
Joined: Oct 2021
Posts: 8
Likes: 0
From: Sc
Fuel pressure issue I recently got my 5.3 swapped 1965 nova on the road for a test drive everything went well got it up to temp. 190 195 something like that fuel pressure looked good around 55 give or take a few psi. Drove it to a buddy of mines house about a mile away no issue cut the car off talked for around 15 minutes got back in and proceeded to drive home. As I pulled in the drive way i heard the fuel pump sound like it was starving for gas. I have a inline fuel pump btw. I didn't think anything of it honestly. A few days later. I went to start it up and fuel pressure was like 75 or so I was like wow that's high so I let it run for a bit and after around 3 or 4 minutes fuel pressure dropped to around 35 and the fuel pump was really loud again like it was starving for gas. New coils, injectors, fuel pump, filter, lines, fuel pressure regulator, and gas tank. It is a return style system 3/8 feed and 5/16 return if I'm not mistaken. any ideas what would cause this. Also I thought it might be low on fuel so I put some more in it and same thing. Oh and I have open headers with O2 sensors
TECH Fanatic
Joined: Jan 2009
Posts: 1,063
Likes: 475
From: Bostwick, GA.
"Should be vented pretty good gas cap doesn't really seat that well and it has a vent tube on the filler neck".
Relying on a bad cap to vent the tank is not "going to get it".
Depending on how the tube on the neck is routed, it may just rely on the cap for pressure escape.
Do you know if the cap is sealed and just in bad shape, or if it's vented by design?
What kind of regulator is this? How is it plumbed?
Relying on a bad cap to vent the tank is not "going to get it".
Depending on how the tube on the neck is routed, it may just rely on the cap for pressure escape.
Do you know if the cap is sealed and just in bad shape, or if it's vented by design?
What kind of regulator is this? How is it plumbed?
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TECH Fanatic
Joined: Jan 2009
Posts: 1,063
Likes: 475
From: Bostwick, GA.
If it's open, I would add some rubber hose, a cheap inline filter and hang the hose up in the body above the top of the fill neck.
Post a pic of what you have.
Also: "Oh and I have open headers with O2 sensors". That may cause tune issues. You MUST have a leak free exh system to allow the sensors to work correctly.
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Verdad Gallardo Thread Starter
Teching In
Joined: Oct 2021
Posts: 8
Likes: 0
From: Sc
Sorry it's taken me a long time to get back to you guys my wife had our first born. Anyway I got some time earlier this week to go mess with the nova. I took off the return hose and ran it into a bucket to make sure the return wasnt clogged. In doing so I also left the nipple for the return open to make sure it was vented properly. I started it up and same issue fuel pressure went to around 75 and ran very rich. So now I'm thinking maybe I got a bad regulator or maybe I need to do away with it and go to a manual style regulator. any thoughts on why this wouldn't be a good idea or do yall recommend me trying to buy another OEM regulator and give that way another shot. I'm open to ideas.
Joined: Apr 2006
Posts: 3,890
Likes: 1,137
From: Grand Rapids, Michigan
The regulator doesn't sound like it's functioning correctly, for sure. Me, I'd run an aftermarket adjustable one. But post some pics, like Old Buzzard said. We might be able to spot a problem that way.