EFI system problems...help!

[Whitey0817]

Ok, ive done extensive searching and my head hurts, think i just need a pointer or 2 to solve this....95 3.0 Auto/4x4....it died the other day on the interstate and i found it to have blown the 15amp efi fuse. Its blowing the fuses as soon as it cranks, but not when i just turn the key to "on". I didnt find a short on the o2 sensor wire. The fuse blows on crank even with the fuel pump unplugged under the back seat which leads me to believe there is a short somewhere along the wiring. I tried running a +12v source directly to the wiring connector to the pump but it sparked a bit on both the blue/black and white/black wires there at the plug connector as if both were touching ground. Im pretty sure the blue wire is the + side right? This is driving me nuts! I also understand the AFM is responsible for sending power back to the pump? So if I were to unplug that there should be nothing going back to the pump? Could it be a blown relay?

Thanks, Dan

 

[92-SR5]

Sounds like a wire is grounding out somewhere it shouldn't be.

 

[Whitey0817]

Thats what ive been narrowing it down to, seems like a logical fix and i do have a nice size hole in my muffler (another day) but that could have melted something...anyone know the routing of the the fuel pump wiring? I dont have it up on a lift, just cold concrete to lay on for me...

 

[willyt4r]

check the wiring on the frame

I had an exhaust burn and melt my wiring also . It was on top of the frame towards the rear drivers side. Good luck

 

[willyt4r]

relay location

the fuel pump relay is in the passenger door side under the glove box

 

[fourwd1]

Ok, ive done extensive searching and my head hurts, think i just need a pointer or 2 to solve this....95 3.0 Auto/4x4....it died the other day on the interstate and i found it to have blown the 15amp efi fuse. Its blowing the fuses as soon as it cranks, but not when i just turn the key to "on". I didnt find a short on the o2 sensor wire. The fuse blows on crank even with the fuel pump unplugged under the back seat which leads me to believe there is a short somewhere along the wiring. I tried running a +12v source directly to the wiring connector to the pump but it sparked a bit on both the blue/black and white/black wires there at the plug connector as if both were touching ground. Im pretty sure the blue wire is the + side right? This is driving me nuts! I also understand the AFM is responsible for sending power back to the pump? So if I were to unplug that there should be nothing going back to the pump? Could it be a blown relay?

Thanks, Dan

There is an interlock switch for the fuel pump +12V in the AFM.

The + wire for the fuel pump is indeed blue and the white/black stripe is -.

If you ran +12V to the white/black wire you created a dead short, so there would be a spark.

If you ran +12V to the blue wire there might be a small spark initially and the pump would run (if it's good).

Locate and remove the EFI Main Relay (above the pass side kick panel), make sure the EFI fuse is good (this will isolate the pump, COR, AFM switch, and some other stuff from the fuse), then crank it.

Whether or not the fuse blows will help decide where to go next.

 

[Whitey0817]

This is a different relay than the efi relay in the fuse box under the hood?

 

[Whitey0817]

Well I think I found the problem...all the wiring along the drivers side frame rail is basically one fat wire...cracked the grommet off and it looks like one of those multi colored candy canes all fused together...time to go get some wire and rig the shit out of it!