So im 93% complete on my turbo install. Im having a weird issue right now regarding my fuel and injectors though. My fuel pressure gauge reads 0 as soon as my fuel pump finishes priming. I thought maybe I had a leak at the injectors but they are as dry as a bone. Is this normal for the fuel pressure to drop so suddenly? Do I need to adjust my regulator up some?
My setup is OBD1 and I have wired in a resistor box to the 450ccs. I have a walbro fuel pump and an aem regulator.
The gauge is on the fuel filter. Until I replaced the injectors, it seemed to hold pressure fine. I guess im confused because normally if pressure is lost, a fuel leak isnt too far behind.
If there’s no leak, then it’s gotta be either a bad gauge or a bad regulator, and it’s probably just coincidence that either one failed when you changed the injectors. Does the car run?
I started it up for like 5 seconds just to see and it did run. It finally stalled out and died though. I have one of Xenocrons basemaps on it for now just to get it started. Im going to take the rail back off I think and check the injectors again. Is it possible that they may be leaking just enough to let air through but not fuel?
The pump is providing pressure to the filter. I had my brother get in and turn the key and the gauge needle moves to about 40. After the relay to the pump kicks off, it dies back down to 0 rather quickly.
Pressure dropping from 40 psi to 0 would be a leak that you’d notice… and smell, for that matter. I’d put my money on the FPR being bad, but it could also be the gauge, or maybe even the fuel pump.
The regulator should hold the pressure at 40psi even after the fuel pump is done priming, and it should stay up there for several hours.
i have the same issue, i am running a walbro 255 with a firewall mounted fpr set to about 40 w/o vacuum. and it preasurizes when the car is on or the pump is running but when the car is off or the pump kicks off the preasure goes to 0, my guess would be that it has to do with the pump because thats the only open end of the fuel system for the preasure to go through.
Well after a quick switch, ive found the issue. The fuel pressure regulator took a crap on me. It was an AEM. Im guessing the diaphram tore when I released the pressure from the rail. I installed a factory FPR I had laying around and it holds pressure now.
Im getting rained out right now but hopefully ill get to hear my engine tomorrow! Thanks everyone for your help.
im using one of the ebay external regulators with no problems going on 5 months. its in-line with a walbro 255, the only thing was i forgot to tighten the set screw one time and the adjuster backed off and lost preasure but i caught it in time
Yeah it does suck the expensive one failed. However, after I read around that I could get the same results on a factory FPR, I wont be looking for another aftermarket in the near future.