Deuce fuel pump blowing fuse

[Woodsplinter]

I've searched through the threads but can't find anything that really covers my situation. I replaced the in-tank fuel pump seal as it was leaking. I re-installed the pump and it wouldn't start. I discovered the fuse had blown. I replaced it only to have it blow over and over.

I remembered reading a thread where the pump might have an internal short, causing the fuse to blow. I removed the pump and replaced with an E-*** $50 one. I couldn't get the plug out of the original pump so I cut it off and used the plug from the new pump. To do so, I soldered the center wire and covered with heat shrink tubing. I then pulled the outer metal sleeve back together, twisted some of the ends together and soldered to make a good connection.

Re-installed new pump and kept blowing fuses. It was then that I discovered I needed to use slo-blo fuses. Replaced with a 5 amp slo-blo and it worked fine for a while. After a few weeks the fuse began blowing again. I covered the fuse with foil and temporarily replaced- pump ran fine, no smoking wires or other problems detected. Don't know what the problem is so I'm hoping the experts can solve the mystery.

Thanks- any help would be appreciated!

Mark

 

[gimpyrobb]

Do you use diesel or "other" fuels? Many run 7amp fuses with oil in the tank.

 

[Woodsplinter]

I only run diesel. I was considering going to a higher amp fuse but haven't because I'm not really sure what the fuse is actually protecting. (The pump, but from exactly what?)

 

[DieselBob]

Might also try checking the voltage at the pump. According to the TM you need a minimum of 23 volts.

 

[Woodsplinter]

Ok, Bob I'll check that tomorrow.

 

[Woodsplinter]

Well, checked the voltage to the pump and came up with 20 volts. Checked the batteries and got 40 volts! What?!
Time to retire my Micronta meter I bought at Radio Shack in 1977.

Anybody know a good, inexpensive meter? Just need something for a homeowner- I'm not an engineer or anything.

 

[gimpyrobb]

Get a basic Fluke meter. Make sure it measures Hz, as that comes in handy when you decide to play with gensets!

 

[197thhhc]

Check your ground for the fuel pump. A bad ground will cause high current draw and pop fuses. Everything should be clean and tight.

 

[Woodsplinter]

Thanks Gimp- I'll start looking. 197 when I replaced the pump I discovered the braided cable that surrounds the hot lead grounded the pump to the holder. Do you think that is a sufficient ground?

 

[gimpyrobb]

Most pumps have a separate ground that goes from the pump housing to the hanger bracket.

Pic:

 

[Woodsplinter]

Ok, I'll check that also. Thanks!

 

[Woodsplinter]

Well, the new Fluke meter says there is 24 volts at the pump, and 12 volts at each battery. (Wow, digital read out is so much better than an analog scale!)

Tomorrow I'll take the pump back out and see how it looks.

 

[Woodsplinter]

I pulled the pump out and discovered the heat shrink tubing I used to cover the hot lead had softened and loosened up. Diesel could get to the soldered repair but it could not short to the braided cable.

I'm not sure if that could have caused a short through the diesel but I need to cover it with something "deisel proof".

I was thinking about 2-part epoxy like JB Weld.

Any thoughts if this will hold up to diesel? If not anything else I could use?

Thanks!

 

[197thhhc]

I dont think JB weld will last. There is a heatshrink butt splice that we use to repair wiring harnesses on cars, we use them in the gas tanks also. You will have to clean the wire insulation with brake clean or alcohol to get all the diesel residue off. Then you just crimp the splice and then heat it and it will shrink and seal the connection. The splice has an adhesive on the inside and it fuses to the wire insulation. Most auto part stores have these. If you cant find them let me know and I will mail you a couple. Ted

 

[Woodsplinter]

Ted, that sounds perfect! Thank you very much- I'll let you know if I can't find them locally.

Mark

 

[Woodsplinter]

Ted, I found the heat shrink butt splices at Harbor Freight. I used one to reconnect the hot lead and re-installed the pump two days ago, using a 6 amp slo-blo fuse.

So far the pump is running fine- I'll post up again if it quits.

Thanks everybody for all your input.

 

[197thhhc]

Thats great. I'm glad its working for you.

 

[leepotter]

I was having the same problem and did exactly what you did same pump and everything. I replaced the WHOLE wire right to the fuse. The original had lost its covering and I think it may have been shorting out and blowing the fuse.

 

[Woodsplinter]

Glad it worked out for you. I thought about doing that but couldn't figure out how to remove & replace the wire where it enters the plug on the pump.

Somehow that needs to be "fuel proof ".

 

[leepotter]

The old wire was a pain to get out. The part the wire goes through was crimped I had to put it in a vise to uncrimp it. Getting the new wire through wasn't easy either. VERY tight fit. Was so tight I dont think it'll leak.