Revdoc

iTrader: (2)

This weekend I spent a day or so installing a new gauge pod and a couple of gauges, including a fuel pressure gauge. I attached the sending unit to the test fitting on the passenger fuel rail after removing the schrader valve. When we first tested it it was reading only 16 psi. I tried to start it and it started, then climbed to ~42 psi. Good enough. Got the pillar pod mounted and everything done, went to start the car and it starts but soon fuel pressure drops to 20 psi and it starts running rough.

Thought the gauge might be bad so I unhooked the sending unit and tested with a mechanical fp gauge at the test fitting on the pass fuel rail. Each prime would only raise the pressure about 2-3 psi. It got to about 15-16 psi then I tried to start it, won't start. Thought the regulator might have gotten stuck open with some teflon tape or something, so I unhooked the feed line at the driver's fender and put the mechanical gauge on it and primed the pump. Same problem, 2-3 psi per prime.

Went to O'Reilly's and bought a Wix fuel filter, replaced that when I got home and still no improvement. I did notice when I replaced the filter that there was hardly any gas in the line, i.e. I didn't spill it all over myself there was just a little hissing when I first loosened the nut.

So now I'm at the point of replacing the fuel pump, or at least opening up the tank and checking the existing pump. Any other diagnostics I can do without dropping the tank or cutting a hatch? The pump runs every time and sounds normal, maybe a little loud so I'm pretty sure it's getting the proper voltage. I've already ordered a Walbro 255 kit from Racetronix just because I will have to get in the tank anyway, might as well upgrade while I'm in there. Any other ideas?

305sbc

iTrader: (3)

Out of gas ?

jermdm

I would suspect the pump going bad. Its possible that you can hear the pump working but not pumping fuel. Had that happen to me before.

strider681

did you get the tank dropped? I had the same problem before and it was the pulsator in between the pump and the sending unit. I replaced that thing twice and the 3rd time i got the submersible fuel hose fom napa.. costs as much as the pulsator but now my fuel pressure holds. oh also I didn't use the worm gear hose clamps they wouldn't seal right, I went with the corbin ones that everybody hates but they seal bett IMO.

Revdoc

iTrader: (2)

Well, I am ashamed to admit it but when we opened up the tank it was dry as a bone. I guess my gas gauge isn't entirely accurate, and I had somehow reset the trip odometer, too. The good part is I now have a Racetronix Walbro 255 kit with an upgraded wiring harness, and I also have a quick access hatch on the package shelf in case I ever need to get in there again.