Fuel pressure issue
#1
Fuel pressure issue
Hello,
Been years since I have been on this site, turns out I had a profile.
I have a 351w pushing 400hp. Mechanical fuel pump system. The mechanical fuel pump is the only fuel pump on my ride.
I have a clear fuel filter up by the 600CFM Edelbrock Carb and the fuel pump is 110GPH pump.
My issue: After starting the engine, I have ~6psi of fuel pressure and the glass filter is full of fuel. After about 1 minute the filter has hardly any fuel in it and the psi drops down to 1 psi or less.
What I have done: I disconnected to fuel line just prior to the pump and put the line into a bucket of fuel. Fired up the engine and still have the same problem.
I don't think this is vapor lock because the engine isn't at operating temperature when the psi drops down. Am I right to assume that the fuel pump is bad?
Fuel Pump: Edelbrock Performer RPM Street Fuel Pumps 1725
Thanks in advance for the help!
StangStang
Been years since I have been on this site, turns out I had a profile.
I have a 351w pushing 400hp. Mechanical fuel pump system. The mechanical fuel pump is the only fuel pump on my ride.
I have a clear fuel filter up by the 600CFM Edelbrock Carb and the fuel pump is 110GPH pump.
My issue: After starting the engine, I have ~6psi of fuel pressure and the glass filter is full of fuel. After about 1 minute the filter has hardly any fuel in it and the psi drops down to 1 psi or less.
What I have done: I disconnected to fuel line just prior to the pump and put the line into a bucket of fuel. Fired up the engine and still have the same problem.
I don't think this is vapor lock because the engine isn't at operating temperature when the psi drops down. Am I right to assume that the fuel pump is bad?
Fuel Pump: Edelbrock Performer RPM Street Fuel Pumps 1725
Thanks in advance for the help!
StangStang
#7
I fired the truck up after replacing the headers prior to pulling the pump and noticed that there was air pumping into the glass filter prior to the carb. It was very noticeable and I got video of it but not sure how to post it.
Possible that the pump is crack at a fitting and or air is leaking through the diaphragm?
Regardless the new one gets here on Thursday and I will try to install sometime this weekend.
#9
I plan on installing the new pump on Friday. I will post results.
Thanks for the reply
#10
You need a larger feed line. 1/2" AT LEAST, and not a soft rubber line, either metal tubing or the stainless braided Teflon so it doesn't try to implode and restrict flow.
Your likely starving the suction side of the pump and boiling fuel as it tries to pass into the pump. Once that happens and the pump starts to cavitate, it can't move fuel.
A 110gph pump is ****ing huge, and is intended to fuel n/a engines with 1,000+hp.
Your likely starving the suction side of the pump and boiling fuel as it tries to pass into the pump. Once that happens and the pump starts to cavitate, it can't move fuel.
A 110gph pump is ****ing huge, and is intended to fuel n/a engines with 1,000+hp.