Help. Dead at roadside. 20Amp lift pump ecm fuse blows

[Will L.]

Ip ground stud is the short ground wire that grounds the to the top of the ip itself with button head screws from the connector that factory plugged into pmd. Remove that little screw and clean the connector, and where it mounts well. Check ringlete has good attachment to wire and reinstall.

Imo:and then ignore it.
I think it will be on the valve itself. Go under the truck and unplug the valve. Cant tell you how bad that is to reach. Then try it. If the ip ground were drawing that many ohms, i would think your truck would be doing some crazier crap than just popping that fuse.

 

[Sand]

So here it is. Grounding. It took careful research through 3 model year manuals to understand the grounding descriptions. One year to explain the terms that are then used as acronyms in the next two without explanation. The body is more or less isolated and all grounds are at specific studs in plastic blocks that go back via a heavy cable to the engine block. The IP (instrument panel) ground had been moved at some point off the stud onto the body. It made a reasonable contact but with wet weather this year created a very poor ground. I finally found it and put it back to a proper ground point. Fuse seems to have stopped blowing. All is looking good.
Thanks guys for the input. These issues are the real tricky stuff and I really do value the experience you all have in diagnostics.

 

[Will L.]

Sorry for the mis info on the ip ground stud. I should know better than to use reason and expect a name to be properly descriptive- haha.
Glad you nailed it down.

 

[deejaaa]

i have nothing to add but i learned a lot from the thread.

 

[Sand]

H- cow. After a week of being fine the 20A fuse blew 2x today. I clipped a curb at costco and it blew 4 seconds after my back wheel hit the road again.
I went home to re- wire my Lift pump as an isolated circuit, then umplug my my dual tank switch to keep it out. This leaves the PMD only. I started to put my PMD extension back in when I found a rubbed wire. I had previously checked it but this time I unplugged it from the PMD, where it enters the loom and the tiny ground wire. It allowed me to pull it out further for inspection. NOW I feel I have it solved.
A lot of my loom protection on the engine is pretty crunchy. I will make a project of replacing it all. Someday.

 

[Will L.]

And you are still sure you dont want to convert to a db2?

Hopefully thats it. What a p.i.t.a.

 

[Sand]

Posted: Sun Apr 16, 2017 10:41 am Post subject:
Oh my days.... This has been going on for 4 months....
Ive been driving around with the tank selector switch disconnected. It keeps the circuit dead and keeps me driving - on one tank only.
Every so often I study my wiring diagram and feel sick thinking about cutting open the loom and tracing it end to end.
Until yoday. I found the wiring travels to the back of the drivers side frame rail, then doubles back a bit and heads over to the passenger side across the top of the heat sheild that covers the muffler. Right above the muffler is a connector. Mine had about 6 inches of wiring that had no protection on it. It had chaffed through on top of the heat sheild. I put a alligator clip on the open wires and if I ground it out for 4 seconds the fuse blows and truck dies. Im so happy. Wrapped it. Loomed it and hope its the last I heard of this.

 

[Will L.]

SWEET!

 

[JMJNet]

Wow, wire gremlins?

 

[Nosferatu49534]

Posted: Sun Apr 16, 2017 10:41 am Post subject:
Oh my days.... This has been going on for 4 months....
Ive been driving around with the tank selector switch disconnected. It keeps the circuit dead and keeps me driving - on one tank only.
Every so often I study my wiring diagram and feel sick thinking about cutting open the loom and tracing it end to end.
Until yoday. I found the wiring travels to the back of the drivers side frame rail, then doubles back a bit and heads over to the passenger side across the top of the heat sheild that covers the muffler. Right above the muffler is a connector. Mine had about 6 inches of wiring that had no protection on it. It had chaffed through on top of the heat sheild. I put a alligator clip on the open wires and if I ground it out for 4 seconds the fuse blows and truck dies. Im so happy. Wrapped it. Loomed it and hope its the last I heard of this.

This is why I hate electrical issues. I have no patience for it....

 

[Sand]

Ive was warned years ago yhat if you became good at electrical issues as a mechanic - keep it quiet. Or else thats all you'll do the rest of your days exclusively.

 

[Nosferatu49534]

Ive was warned years ago yhat if you became good at electrical issues as a mechanic - keep it quiet. Or else thats all you'll do the rest of your days exclusively.

So you wanna come over? Lol.

 

[Sand]

Im not that guy. I replace skill with zen like plodding along patience. Enough time invested will eventually get you there too. Same way you can become a millionaire working at Macdonalds - by working a million hours.