So I've had a loss of power and a low fuel pressure (22psi) for a month now, and I can't seem to pinpoint the problem. I've replaced the fuel filter and fuel pump but the pressure hasn't changed. Any ideas of what the problem could be?

PS also I removed the vacuum line from the fuel pressure regulator and the pressure goes up by about 10 psi, and when I pinch the return line shut, the pressure shoots up to about 80. dont know if that's normal or not

 

Turn the gas on .

 

Fill your info in !! - What vehicle are you talking about ???????? - A moped ? R we suppose to guess?

 

whats your vacuum like to the fuel pressure regulator? you should see a steady pull @ idle of about 20 in IF you have an N/A motor.

 

Yea, or "IF" it's a Honda , just whined the rubber bands a little tighter

 

Yeah sorry, 2001 4.2 107k miles, N/A with bank 1 and 2 lean codes.

 

Yea , you need to go thru it, the fuel system, regulator and whatnot. Find the relay, I doubt that's it , but feel to see if it's hot. If the relay is hot - It's bad.

You getting the same pressure reading you did with the old pump? That sounds like the regulator or sticky injector.

Not to common of a problem, you have a Haynes or Chilton's book? Something with the spec pressure numbers ? I'll post the Fuel sheet and give yuh a fault finder link to check out -



Fault Finder Link -

http://www.fordscorpio.co.uk/faultfinds.htm

Do you have a Vac Device to apply vac when checking the regulator ?

Spec #'s

Fuel Pressure @ idle ~ 30 - 45 psi
Vacuum hose attached ~ 40 - 50 psi
Vacuum hose detached ~ 30 - 40 psi
Fuel system hold pressure (after 5 minutes) ~ 30 - 40 psi
Fuel pump pressure Max ~ 65 psi

Connect a hand held vacuum pump to the fuel pressure regulator and read fuel pressure w/vac applied. Pressure should decrease as vacuum is increased.

You can also detach the vacuum line from the fuel pressure regulator and verify vacuum is present when the engine is running.

 

Alright, I did the test where I pull the vacuum hose from the FPR and the pressure increased. it went up to ~30 psi. Also If the problem were the regulator, how would I go about replacing it? I took a look at it and it appears to be welded to the fuel rail. Would I need to replace the entire fuel rail if my FPR is bad?

 

Take a closer look @ it - It unbolts from the rail and I believe it has two little o-rings inside. Make sure when purchasing a new one - get those o-rings as well. They prolly come with it, but question it.