fuel pressure regulator and fuel return pressure

[chetacheese]

couple questions, hope you guys can help.

i think my fpr is clogged because when i unhooked the fuel pressure feed line and there was pressure. i unhooked the return side and empty and no signs of fuel. im wondering is there supposed to be pressure there or do i just have a clogged fpr

[jspaeth]

couple questions, hope you guys can help.

i think my fpr is clogged because when i unhooked the fuel pressure feed line and there was pressure. i unhooked the return side and empty and no signs of fuel. im wondering is there supposed to be pressure there or do i just have a clogged fpr


There are a few relevant questions that need to be asked.

How long after the car was run did you do this, and if the car wasn't previously run, how long ago was it run?

After letting the car run for even a few seconds, if turn it off and unhook the return side of the FPR, there should DEFINITELY be fuel in there.

However, if the car has sat for a WHILE, then it's possible there won't be any fuel in that part of the line.

[chetacheese]

well i bought a used greddy fuel rail and it included the fpr(stock). i didnt test it or anything, so im trying to troubleshoot by figuring out how it works and how its supposed to be. so i cranked the engine but it wouldnt turn over. i dont think its getting any fuel. so the feed side, theres fuel squirting out when i loosened it. but the return side, there was no sign of fuel at all. so im thinking it could be the fpr thats clogged.

the vacuum line that goes to the fpr opens the valve for fuel am i correct? i read this somewhere on one of the threads i searched. where is that line supposed to go exactly. i removed my emissions and i have my fpr vacuum hooked up to the intake manifold near the brake booster line.

[chetacheese]

narrowed down. MY FPR DOESNT OPEN UP FOR FUEL FLOW TO THE RAIL. WHAT CAN THIS BE?

[chetacheese]

umm help, does anyone know what allows the fpr to open. or at least link me towards the right direction?

[cotbu]

Fuel flows from the pump through the lines, to the filter...to the RAIL through the FPR back through the line into the tank. SO your line are probably assbackwards GET an FSM it help with small frustrating problems, that could have turned costly

[drftem]

yes you will get fuel to the injectors prior to the fpr. The fpr opens to maintain a certain fuel pressure. It is more like a relief valve.

[chetacheese]

thanks for your input, ill double check.