Fuel pump went out. Wiring or pump?

[rampage]

…when it leaves you stranded …

No pun intended I'm sure.

 

[DK5]

you damn near won a darwin award for that.

Yep now I'm out at least $150.
Oh well at least I was smart enough to not blow anything up

 

[jeff in co]

I just went through all this wiring checking thing. When the brand new pump was connected, it ran sometimes, other times, not.

With the help in here, I was able to pinpoint my problem. The previous owner did a solder joint wire connection right at the electrical pump connector. I was loosing just a little amount of juice to make the new pump not run reliably. A very small item that I would of assumed was good otherwise. Re-did connector and my truck has run ever since (going on a month now).

 

[jekquistk5]

Yep now I'm out at least $150.
Oh well at least I was lucky enough to not blow anything up

Fixed.

 

[soonertodd]

True dat. Live and learn. One thing that must be said is ALWAYS keep in mind safety first.
When I performed this test, even though I did it wrong, I had it outside and away from anything combustible.

That's good,it would have just killed you outside

 

[DK5]

So. When i get back out there, I'm going to plug the new pump that I picked up from Canadian Tire for $100
Will plug it in to harness on frame, attach ground to frame, turn ignition and see if pump hums. If no hum, I know for sure electrical. Will trace wires and use my GM repair manual to track the circuits, replace with new line to spec, will use proper crimps and heat shrink. Once I know all is good, will attach pump to (emptied) gas tank and reinstall.
Its going slow, but its my free time project. I'm not a mechanic, but I'm handy and willing to learn. Thanks all for your input.

 

[mechted]

The pump is designed to have fuel in it for cooling and lubrication purposes. Shouldnt be a problem if you are just bump testing it, but dont run it any longer than you have to. Easy way to waste another pump.

 

[jekquistk5]

The pump is designed to have fuel in it for cooling and lubrication purposes. Shouldnt be a problem if you are just bump testing it, but dont run it any longer than you have to. Easy way to waste another pump.

Was just going to say that.

 

[diesel4me]

Me too--even running out of gas can kill a good pump !..

 

[DK5]

Roger that. Thx guys

 

[DK5]

Can anyone tell me exactly where to find the wires that go from the pump to what in the engine bay? Would make it easier rather than trying to follow them up the frame rail

 

[jekquistk5]

Follow up the frame rail is probably the easiest way to do it. If you are having wiring issues its best to split the loom and trace each one back looking for cracking, bad splices, and arcs. But they should end at the bulkhead.

 

[DK5]

End at the bulkhead? What bulkhead? I think I'm going to replace the whole harness

 

[jekquistk5]

Hahah. The bulkhead that passes through the firewall into the cab and goes to the fuse panel.

 

[sweetk30]

efi pump wires on trucks run with the tail light harnness down the frame rail left side.

 

[DK5]

Comes down framerail, in a black wire loom and up the firewall. Gets difficult to differentiate the wires at this point. Anyone know the colors? Checking my repair manual...

 

[dyeager535]

Can anyone tell me exactly where to find the wires that go from the pump to what in the engine bay? Would make it easier rather than trying to follow them up the frame rail

Comes down framerail, in a black wire loom and up the firewall. Gets difficult to differentiate the wires at this point. Anyone know the colors? Checking my repair manual...

Repair manual? I hope you mean GM electrical diagram.

 

[jekquistk5]

http://www.73-87chevytrucks.com/techinfo/7387CKMans/Wiring/ST_350_89_1989_GM_RV-P_Light_Trucks.pdf

 

[DK5]

Repair manual? I hope you mean GM electrical diagram.

Ya I have the GM service manual with electical diagrams, same as what's in your sig

 

[DK5]

http://www.73-87chevytrucks.com/techinfo/7387CKMans/Wiring/ST_350_89_1989_GM_RV-P_Light_Trucks.pdf

That is very helpful thanks