lift pump will not run
 

I am out of ideas and need your help. I started my truck for work yesterday and it started fine. I went in side for coffee and to let it warm up but when I came back out the truck had died. The truck would not restart. It was cold and snowing, (spring time in Colorado) I called off work and waited for the sun to come up and warm up some, 8:00 Am the truck started and ran fine, I thought water/ice or bad fuel filter, so drove to the auto parts store, made a couple stops along the way, got a new filter, ran fine. Left the parts store and the truck died one block away. I had the truck towed home, no noise from the lift pump, Dodge installed the in tank pump at 75K I have 205K now. Replaced filter and pump with new pump from A. Z. no noise from pump! No fuel! Replaced pump with pump from Napa, No noise! No fuel! I cleaned ground wire on battery for ECU, no joy!
Called my local shop they can’t look at it till Monday or Tuesday. Does anybody have any ideas? Thank You

2003 Dodge Ram 2500 HO 6 spd all stock

Check the fuse, check the power at the pump.

I don't have a FSM for an 03, but does it have a lift pump run relay?

I'm pretty sure... let me check.

Nope. 12v from the ECM.

I can not find a fuse or relay. Can an ECM go out like that work not-work work then not work? I was so sure it was the pump.

Yeah, it's electrical, when it degrades, it could fail slowly.

First thing I would do is check power to the pump. If you have power to the pump, you know it's the pump. If you don't, trace the lines back.

If you find your power for the pump, turn the key on and bump the starter. You'll have about 30 seconds of power to the wire before the ECM cuts it off.

If you don't have power at the tank for the pump, trace the wire back to the fuel filter canister... there should be a splice there for the in tank pump modification, see if you have power there. If not, you may be looking at an ECM issue.

You should have a FP fuse... let me look into that.

I got nothing on a fuse or a relay...

If the retro pump was installed there is a fuse pigtail off the battery on drivers side going to a relay most likely plastic tied to harness on firewall. Pull the fuse and see if it is blown first. I've seen fuse blow if not pushed in all the way, fuse gets hot and blows usually will be discolored from heat, poor connection..I have installed retro many times buy once a truck came back on the hook.[duhhh] I didn't check fuse after install, and it wasn't pushed in all the way and fuse blew out.[dummy]

Thank You! Thank You! Thank You! I am back in business!

BigIron70 you sir are a genius!

The fuse for the fuel pump is inline on the wire from the driver side positive battery and the relay is zip tied to a wire harness on the firewall. This is added during the pump relocation and not mentioned anywhere I have found, so keep this in mind. My fuse was arcing and burned on the side. Must have happened when the pump went bad. And yes I am sticking to that story.

Glad you got it figured out, man.

I've never messed with one of the retrofits, so I learned something too. Good stuff.

That makes 2 of us. Glad BigIron works on this stuff on a routine basis. That's why I stick to this site......the wealth of info here, IMO, is second to none.