Working on my brother's truck. For a few days it was taking longer to start than the usual crank crank vroom. It's a good running 5.9. Anyway, truck won't start, pull the fuel lines at the filter and no fuel. Changed the fuel pump, old one worked fine when hotwired to a 12v supply. Put the new one in anyways w/ new screen and filter. I don't think we're getting power to the pump. Also, got a fuel pump relay from the autostore but can't figure out where it goes. The only plug that it fits in the harness up by the driver's side fender doesn't currently have a relay in it. There are two other similar shaped plugs on the fender but both don't quite plug in to the new relay.
Any thoughts?

 

There should be at least 2 and maybe 4 relays on the fender just below the hood spring. The front one is the starter relay, second is the ASD/fuel pump relay, third is A/C clutch cutout relay, last is part throttle unlock relay. Sounds like your ASD/fuel pump relay is missing and that will keep the pump from running. I have never heard of one falling out but strange things happen. Plug in the new relay to the plug it fits and see if the pump comes on when you turn on the key. You should be able to hear it run.

 

I got a new ASD relay today, actually came with two so whichever those are have been replaced. Still nothing. When the key comes on I can't hear anything. I got a #42 code thrown and checked out the OBD codes and it was an ASD error, that's why I replaced it. Right now I have both lines to/from the filter unplugged so I can see if it starts to **** fuel out. Short of dropping the tank again and checking for power at the pump I'm at a loss. I'd surely not like to mess with the top of the tank again if I don't have to. What wire am I looking for if I go under there w/ a tester? I believe I read somewhere it's a green wire, is that correct?

 

Ok so I poked around under the bed and I have power to the blue/striped wire, not the green/black wire that I thought I was supposed to have. One thing though, and I didn't think about this 'til I got back home. Would a corroded battery connection cause this sort of problem? Just curious if I should clean the terminals.

 

ASD RELAY
Power to the ASD relay is thru the 14 gauge red wire, power out to the pump is thru the 14 gauge blue/black wire, power from the ignition switch and the A/C wide open throttle relay is thru the 14 gauge blue wires, and the final 20 gauge blue/yellow wire goes to pin 51 on the computer. You should have constant power to the red wire and switched power at the blue wire.

PUMP
The blue/black wire from the ASD changes at a splice to a 16 gauge green /black wire that then feeds the pump. The blue/yellow wire is for the fuel gauge sending unit, and the gray wire is the ground.

 

Did alot of prodding around tonight w/ some jumpers and test light. Long story short, I have power to the fuel gauge sending unit via the blue/yellow wire. No power to either the blue/black out of the ASD or the green/black out of the other relay (there's two relays, not sure which is what). Anyway, I jumper direct from the battery to the blue/black, check power at the green/black at the pump and nothing. So I jump from the battery to the green/black out of the relay and I have power at the green/black at the pump which leads me to believe there is no splicing and changing colors going on. Anyway, I create power to the green/black like mentioned and still no pump action. Leads me to believe it's a grounding issue. I followed the two white(or grey) wires from the pump but they soon narrow down to one wire tucked tight against the framerail. Also, the fuel gauge doesn't seem to move when the ignition is turned on. Yesterday it was showing 1/4 tank, today it's flat empty. Not sure if this is related but what I'm getting at is I know there's power to the sending unit and it's not relaying to the fuel gauge. Not really sure what my next step is right now.