Hey guys, having a prob with the Burb. 93 5.7 TBI that I've owned for about 5 months now, with no problems. Came out of Starbucks the other day and she cranked with no start. Good crank, never had a start issue before, usually fires right up and runs great. Thought I was out of gas, so I came back two hours later dropped in a few gallons and she fired up. I drove to the station and put $30 in, and again no start. Spliced in an extra fuel pump and hobbled her home.
Did some testing and found that the voltage to the pump was only 4 volts (grey wire on the frame rail). The voltage out of the Fuel Pump Relay was at batt voltage (grey wire) 10.5 volts. Suspected the Fuel Pump Oil Pressure Switch and changed that. No start. No oil pressure gauge, but wouldn't the idiot light on the dash let me know if the oil pressure was too low to start?
Seems to be a common prob, this "low voltage at the grey wire to fuel pump"
Just wondering if any one else has experienced this? Some times if the rig sits, I can go out and start it right up, but if i shut her down she wont restart.
????

when you turn the ykey on do you hear the pump when it wont start?

if not,,,,, give the tank a good whack with the key on and see if you hear the pump cycle?

if so,,, just change the pump

x2 on the whack the tank. IIRC the pump should cycle with the key on and then OPS should take over after its running. i don't know about the low voltage on the grey wire

Re tested after I replaced the OPS and now I'm getting 12 volts. So it seems that the fuel pump is the culprit. dang!
I've read a lot of horror stories on the net saying the the replacement pumps only last a few weeks and are noisy. Looks like I'll have to find a Delco. Sounds expensive.
Not only that, but I have a trailer hitch to deal with and the Burb is tight up in there around the tank. Not looking forward to this project!!