low fuel pressure....
 

hey guys, just had my engine built and i'm having an issue, i have tried searching to no avail, the engine builder brought it to my attention that my fuel pressure is low and will not register anything above 35psi, i just changed the fuel filter and fuel pump to a walbro 255lph, any idea where i should look next?, when i turn the key to on i hear a groggy sounding noise from inside the car, not sure if it's worth mentioning or not, however, my next idea was to change out the fuel filter in the engine bay, what do you guys think or suggest?, i'm tuning here pretty soon and would like to have the thing ready!...

i have the extreme fuel system from rx7store installed with the aeromotve FPR with jegs guage, 550cc primaies and 1600cc secondaries....

thanx for your help in advance!...

Wait, you said you just changed the filter. is there another filter hiding someplace on the car i don't know about?

The fuel filter is located in the engine bay by the drivers feet. That is most likely your problem.

Though it could also be the fuel tank is rusty and is messing your pump up like it did mine:

http://www.pballandmore.com//images/100_1828.JPG

That was a brand new pump and sock just a few days before and a few hours of run time. killed the pump and the filter with all the rust.

I had to replace the tank there was so much rust actually, though i could have cleaned it out if i wanted to.

holy crap dude, that's insane!...

we changed my pump and the sock/filter that is on the pump itself, it was clean but we changed it regardless....

it DEFINITLY did NOT look like that, lol....

i'll try the one in the engine bay, i hope it works!...

I thought the stock fuel pressure regulator kept the pressure at 35psi for the most part... I could be wrong, it may bump the pressure TO 35psi once there's some vacuum applied (as in it'd be lower at idle or some such), or it might bump it past 35psi. Check the FSM.

Unless you aren't using the stock fpr.

well just because it was clean when you put the sock in doesn't reallt matter. The sock on mine was brand new just a few days before that picture.

I only took it back out after my fuel problems started coming back after a few days.

With those injectors you are obviously running some kind of fuel management system, and if so, does it run your fuel pump relay resistor properly and/or has it been bypassed?

oh, durr, Aeromotive FPR... yeah, resistor relay is a good question.

IIRC when power is going through the resistor fuel pressure should be around 35ish, and when the relay is tripped it should be around 40ish. Don't quote me on this as I don't remember for sure and i'm too lazy to look it up right now, but 35 all the time sounds low.

i have a power FC for fuel managment, as for a resistor relay, i have no idea, everything in the gas-tank area has not been touched other then an upgraded walbro fuel pump....

The resistor relay is located under the stock air box, in the front right corner of the engine bay; check and see if it's still there. I don't know if a PFC controls that properly or not, but I won't be surprised if it dosn't. You might want to read through the PFC forum to see if anyone has written about such an issue.

There is a hose on the pump assembly. Did you also make sure that the clamps are on tight on the pump and on the and on the assembly. If not, you wont pass 10psi of fuel pressure. Instead your fuel is having a very nice show inside the tank...like some kind of fountain in Vegas or something.

well the pressure is around 35psi however but jumps and flucuates between 35 and 25psi, i will have an update after the weekend when i swap the fuel filter....

so after checking the guage today it sits at 35psi while the car is idling, but when i turn the car off it stays there and eventually drops ( 20mins'ish later ), is that normal?...

when i rev it the needle does not move....

idea's?, maybe it's a defective fuel pressure guage on my FPR?...