Electrical Mystery

[Daysu47]

Thought it was fixed but.......

On first day of vacation traveling at 65mph engine just dies, quits running. Checked out and finally found blown fuel pump fuse, 20 amp.
Replaced fuse, started up, drove 20 miles, blew again, bought more fuses, drove 35 miles to RV park, spent 2 days, had fuel pump assembly and filter replaced on Monday. Note: Called Workhorse and Winnebago, both said must be fuel pump.

Left on vacation again, drove 98 miles, fuse blows again. Replaced fuse.

Personal mechanic returned my call, he thought it was the fuel pump relay, drove another 130 miles no problem, parked overnight.
Next morning drove another 110 miles, bought fuel pump relay, replaced, continued vacation consisting of another 1400 miles, no problems. Returned home.

Following weekend went out on weekend outing, drove 230 miles round trip, no problems.

RV sat for 4 days, left this morning to take to dealer for other repairs, FUSE BLEW AGAIN!!!

Any thoughts??? Need help!!

Workhorse W-22 8.1 2002 Chieftain, 45000 miles

Thanks,
David

[Daysu47]

Thought it was fixed but.......

On first day of vacation traveling at 65mph engine just dies, quits running. Checked out and finally found blown fuel pump fuse, 20 amp.
Replaced fuse, started up, drove 20 miles, blew again, bought more fuses, drove 35 miles to RV park, spent 2 days, had fuel pump assembly and filter replaced on Monday. Note: Called Workhorse and Winnebago, both said must be fuel pump.

Left on vacation again, drove 98 miles, fuse blows again. Replaced fuse.

Personal mechanic returned my call, he thought it was the fuel pump relay, drove another 130 miles no problem, parked overnight.
Next morning drove another 110 miles, bought fuel pump relay, replaced, continued vacation consisting of another 1400 miles, no problems. Returned home.

Following weekend went out on weekend outing, drove 230 miles round trip, no problems.

RV sat for 4 days, left this morning to take to dealer for other repairs, FUSE BLEW AGAIN!!!

Any thoughts??? Need help!!

Workhorse W-22 8.1 2002 Chieftain, 45000 miles

Thanks,
David

[DriVer]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Daysu47:
RV sat for 4 days, left this morning to take to dealer for other repairs, FUSE BLEW AGAIN!!! </div></BLOCKQUOTE>David, As unlikely as this might sound I'm going for a pinched wire someplace in the harness that runs to the back of your motorhome. Too bad that it took this long to manifest itself as a recurring problem.

Everything else has been ruled out at this point I believe you said. In the cabling industry, I might use a TDR, time domain refractometer, to tell me where a short or open exists in a piece of twisted pair cable however I do not believe the technology exists for automotive wiring.

Whether or not this condition is manifest by the vehicle moving or not could be important and you did share that the problem presented more than once while the vehicle was moving. On this last failure you said that the fuse blew immediately. Might be that whatever was rubbin' already rubbed through and is presenting a short.

This is going to be a big pain to isolate and get er fixed. I wish you a speedy resolution to this problem.

[Brazels RV Performance]

Check the connector the hooks the front & rear harness together.We had one doing the same thing,the harness was corroded & not making good contact.We ended up replacing the rear half of the harness.

[suspension_engineer]

David,

We wear through wires testing pretty regular. The circuit you are having difficulty has a leg that goes through the main connector in the engine compartment. This is a very large connector that actually gets screwed to the mating part through the center. We have had several wire shorts from behind this area. You will be looking for a rather thick (12 gage) gray wire.

The other leg of the circuit that travels back to the pump is gray 12 gage as well but travels through 1 splice and a 15 pin rectangular connector in the engine compartment. After the connector it changes to a gray 16 gage back to the pump.

Good luck, I spend more time chasing electrical problems than actually testing these days.

[troth]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">the connector that hooks the front & rear harness together </div></BLOCKQUOTE>

Good advice Mike! Can you describe about where that connector is located? (up near engine? halfway back on the coach frame rails?, or....?)

[Brazels RV Performance]

It was located above the transmission crosssmember inside the frame rail on the passenger side of the coach.

[wa7hra]

A good friend of mine had three fuel pumps replaced on warranty from the time he left the dealer with a new motorhome in Ilinois and his arrival in Mesa, AZ.

At the third WH authorized shop in Mesa, the installing mechanic happened to be under the MH when it was started and observed smoke coming from the harness near the tank. Further investigation revealed a pinched wire. A simple crimp on wire splice solved the problem.

Bob...

[DriVer]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Brazels RV Performance, suspension_engineer </div></BLOCKQUOTE>I continously appreciate the support that you give the members of this website. Thank you so much.