File line check valve
Thread Starter
Launching!
Joined: May 2013
Posts: 270
Likes: 30
From: Detroit
File line check valve Hi. I have an intank Walbro 400lph pump, with 3/8” supply and return lines. The FPR is on the back side of the fuel rails.
Occasionally I get long starts, where it struggles.
When I had the car tuned my tuner told me I should have added a check valve.
Researching this, it does not seem very common. It seems the pump and regulator should hold the fuel from draining back to tank. Thoughts?
Occasionally I get long starts, where it struggles.
When I had the car tuned my tuner told me I should have added a check valve.
Researching this, it does not seem very common. It seems the pump and regulator should hold the fuel from draining back to tank. Thoughts?
TECH Fanatic
Joined: Jun 2003
Posts: 1,869
Likes: 99
An external FPR will NOT hold pressure at 58 psi. All of the research I did the consensus was that over time the pressure will decrease after key off.
When you wired the pump did you upgrade the harness? If wired correctly the harness ties into the stock harness so with key on the pump primes for three seconds and then stops if the car is not started (KOEO - key on engine off). Have you tested fuel pressure at the rail during the first three seconds with KOEO?
My Racetronix dual 510 LPH pumps will hold pressure at about 35 to forty psi for about 24 hours and then gradually bleed off with a Racetronix FPR. Racetronix website states that the FPR will not maintain a static 58 PSI with key off. It is a boost referenced FPR.
Aeromotive says the same (link below).
https://aeromotiveinc.com/tech-help/...fi-regulators/
http://performancefuelsystems.com/te...kdowntest.html
When you wired the pump did you upgrade the harness? If wired correctly the harness ties into the stock harness so with key on the pump primes for three seconds and then stops if the car is not started (KOEO - key on engine off). Have you tested fuel pressure at the rail during the first three seconds with KOEO?
My Racetronix dual 510 LPH pumps will hold pressure at about 35 to forty psi for about 24 hours and then gradually bleed off with a Racetronix FPR. Racetronix website states that the FPR will not maintain a static 58 PSI with key off. It is a boost referenced FPR.
Aeromotive says the same (link below).
https://aeromotiveinc.com/tech-help/...fi-regulators/
http://performancefuelsystems.com/te...kdowntest.html
Thread Starter
Launching!
Joined: May 2013
Posts: 270
Likes: 30
From: Detroit
An external FPR will NOT hold pressure at 58 psi. All of the research I did the consensus was that over time the pressure will decrease after key off.
When you wired the pump did you upgrade the harness? If wired correctly the harness ties into the stock harness so with key on the pump primes for three seconds and then stops if the car is not started (KOEO - key on engine off). Have you tested fuel pressure at the rail during the first three seconds with KOEO?
My Racetronix dual 510 LPH pumps will hold pressure at about 35 to forty psi for about 24 hours and then gradually bleed off with a Racetronix FPR. Racetronix website states that the FPR will not maintain a static 58 PSI with key off. It is a boost referenced FPR.
Aeromotive says the same (link below).
https://aeromotiveinc.com/tech-help/...fi-regulators/
http://performancefuelsystems.com/te...kdowntest.html
When you wired the pump did you upgrade the harness? If wired correctly the harness ties into the stock harness so with key on the pump primes for three seconds and then stops if the car is not started (KOEO - key on engine off). Have you tested fuel pressure at the rail during the first three seconds with KOEO?
My Racetronix dual 510 LPH pumps will hold pressure at about 35 to forty psi for about 24 hours and then gradually bleed off with a Racetronix FPR. Racetronix website states that the FPR will not maintain a static 58 PSI with key off. It is a boost referenced FPR.
Aeromotive says the same (link below).
https://aeromotiveinc.com/tech-help/...fi-regulators/
http://performancefuelsystems.com/te...kdowntest.html
The fuel pump relay is driven by the stock ECM. It does the fuel prime.