Ok. I have my truck fully bagged, both compressors hooked in and relays hooked up right. Everythings grounded properly on shiny metal. The bed is grounded to the frame.

heres the prob.

You hook the compressors up to the power source, the fuel pumps ground wire gets melting hot. Without compressors hooked up, its pulling a clean 13volts, hook the compressors up and it cuts in half to 7volts. Im starting to run out of ideas on what to do.

Someone please help

 

sounds like you need a new power source for your compressors

 

how much you wana bet someone hooked the power side of the relays for the compressors to your fuel pump power..

 

I bagged the truck, and nothing was wired wrong. I wired everything straight to the battery, and wired my pressure switch to a power source. Nothings wired to the truck harness.

 

have you checked voltage at the battery with the compressors on? You might just be taxing the hell out of your electrical system. These trucks only have a 65 amp alternator stock. Two decent size compressors will draw 35- 80 amps by themselves.

The other possibility is you have your battery wire and trigger switch mixed up on the relay (it will still work the same , except for the melting wires.)

 

well ive had the relays double checked by myself and another guy, and those are wired up right.

Its pumping at 14amps with the truck running and when the comps come on the its pulling around 13. Im thinking it might be the alternator have problems charging, idk. But would that honestly cause the fuel pump grounds go crazy?

 

You have your amps and volts mixed up

where are your compressors grounded in relation to the fuel pump ground?

 

yeah running its doing 14VOLTS lol my bad then with compressors the fuel pump cuts in half to 7volts

i have them grounded to the bed, then the bed grounded to the frame.

 

What's the status on your alternator?

 

just had it checked, and they said its putting out 15amps. That doesnt sound right to me, but they still said it was good. Not good enough though, that just about has to be why the fuel pump grounds are getting hot. Im taking it to a guy that rebuilds them tomorrow and see what he says.

 

To rebuild an alternator all you have to do is take it apart with a small socket wrench and a screwdriver and change the brushes. The brushes are dirt cheap.

 

So you grounded your compressors to your bed, then you are hiping the bed bolts are enough to ground to the frame...before you do all this work to your alt why don't you ground to your frame and see what happens. I'm wondering if you bed isn't as grounded as you think and youare getting some weird feed back through the fuelpump ground.

 

when you grounded the bed to the frame, did you actually run a wire as thick as your power wires to the compressors to the frame?

think of electricity like water... you cant have a water pipe flowing full blast through a 2 inch pipe draining down a 1 inch pipe without it getting backed up and having excessive pressure, busting pipes etc..

If you don't have a good enough ground for your power to flow back to, you will build up excessive electrical pressure... which translates to excessive heat, melted wires, and sometimes a mysterious white smoke

 

dillinja666, I'll try grounding directly to the frame, but in my first post i stated that i had the bed directly grounded to the frame.

Trap, its between a 4 and 8 gauge wire.

 

grounds are good. alt is good. ive ran out of ideas. im thinking about running a 2nd battery as a last resort.

 

any other sugestions? im checking everything ground wise under the hood tomorrow evening. Have to have this running before saturday.

 

where;s your pressure switch getting its power from? also do you have a good body ground back to the motor? ive seen people with crap grounds from the body to the motor cause some really werid issues.

 

If you havent done it already, upgrade the big 3 on your truck.

upgrade the alternator positive to battery positive, battery negative to chassis, and engine ground to chassis to 4 gauge.

 

Have you tried taking out your pressure switch an just running your compressors to a toggle switch? That's how I have mine done. I'm not a big fan of pressure switches though.