low fuel pressure
Thread Starter
Instructor
Joined: Jun 2001
Posts: 188
Likes: 0
From: nova scotia canada
low fuel pressure
guys--
Car running fine one day and the next fuel pressure was down from 7-8 psi to 2 psi and when cruising car surges, not enough fuel but can't see why.All new russell braided lines with russell filter,1 year old holley fuel pump(110 gph)
thanx for any advice wade
Car running fine one day and the next fuel pressure was down from 7-8 psi to 2 psi and when cruising car surges, not enough fuel but can't see why.All new russell braided lines with russell filter,1 year old holley fuel pump(110 gph)
thanx for any advice wade
Burning Brakes
Joined: Nov 2000
Posts: 948
Likes: 0
From: Johnston Iowa
Are you using a mechanical or an electric 110 gph pump?
If its a mechanical pump take a close look at it and make sure you do not see any fuel or oil seeping out the weep hole on the pump.
If you do the diaphram in the pump has failed which is causing your low fuel pressure I do believe.
If its a mechanical pump take a close look at it and make sure you do not see any fuel or oil seeping out the weep hole on the pump.
If you do the diaphram in the pump has failed which is causing your low fuel pressure I do believe.
Burning Brakes
Joined: Jan 2004
Posts: 1,202
Likes: 2
From: Bergen County NJ
I have a similar issue that I hope will be corrected. Sorry if I'm hijacking.
Before my visit to the shop a couple of months ago, the car had a mechanical 80gph fuel pump and was showing between 7-8psi on the gauge. The shop found that the fuel pump was puking oil and replaced it, however, they replaced it with the stock AC Delco pump for a 327. I also had new fuel lines and new lines from the pump to the carb put in (I've got a 383 stroker with a Holley 650 double pumper). However, when I got the car back the gauge was only reading 4 psi, which the shop said was normal (I guess normal for a 327 with stock carb).
Concerned about the lower pressure, I called Holley and they recommended their 110gph mechanical fuel pump which the shop is installing now (had to take it back for other issues). The instructions for the Holley 650 say that pressure at idle should be 7psi, so all of this makes sense and I'm hoping will correct the problem.
My only concern is that the new fuel lines and lines from pump to carb are 3/8". In researching this in other threads, it appears that thicker lines may be required only for larger blocks / carbs and I may be OK. Any opinions on this? Wade - hope you resolved your issue.
Thanks
Before my visit to the shop a couple of months ago, the car had a mechanical 80gph fuel pump and was showing between 7-8psi on the gauge. The shop found that the fuel pump was puking oil and replaced it, however, they replaced it with the stock AC Delco pump for a 327. I also had new fuel lines and new lines from the pump to the carb put in (I've got a 383 stroker with a Holley 650 double pumper). However, when I got the car back the gauge was only reading 4 psi, which the shop said was normal (I guess normal for a 327 with stock carb).
Concerned about the lower pressure, I called Holley and they recommended their 110gph mechanical fuel pump which the shop is installing now (had to take it back for other issues). The instructions for the Holley 650 say that pressure at idle should be 7psi, so all of this makes sense and I'm hoping will correct the problem.
My only concern is that the new fuel lines and lines from pump to carb are 3/8". In researching this in other threads, it appears that thicker lines may be required only for larger blocks / carbs and I may be OK. Any opinions on this? Wade - hope you resolved your issue.
Thanks
