Sudden Electrical/IP issue...

N.E fjord-by-fjord 2fiddy

Full Access Member
Joined
Nov 22, 2013
Posts
210
Reaction score
1
Location
Maine
Ok. I have to get to the store to get diesel for my truck AND the furnace, since we ran out while I was at work today and the oil guy cant come til monday.

First, the setup: Stock everything (7.3T) except the Carter elec. pump on my frame rail, run off a relay that gets it's close 12v from the top of the IP.

Ok... So I got home, and in a rush I went to do my new cold start ritual. (oh yeah, my GPC solenoid is crap). I turn the key to run (pump starts, but I kill it w its ground lift switch to not burn it out pumping into a still engine). I then go out to bridge the solenoid. In the friggin' dark... Usually, i've got a good sense of where the copper hammer I use is, even if its dim... But I think I may have accidentally bridged the full amperage to the pole on the GPC that has the two red wires, one of which I believe is the 12v+ signal wire that goes to either the IP, or the starter solenoid (iirc, it's the IP... the tippy top connector.

I tested the pump relay's worth by bridging it, and the pump came on. So, the relay might be bad, but i replaced it w a switch, kept the pump on, and re-glowed my plugs again... and with the key in run, the pump on, and heated plugs........ she just turns and turns and turns....... almost as if the internal IP switch is set to "oh no you friggin' don't"

It's cold in Maine. Any help would be very much appreciated. Any more tests I can do to narrow it down would help as well, if no one has a straight up solution. I already disconnected the batteries and she'll sit that way before I get any help. Thanks!

(i'll also mention that this setup I put in has worked well for over a year. the gpc bridge thing I started a couple months ago when the replacement solenoid failed... twice. belkin too... i gave up and grabbed the hammer!)
 

N.E fjord-by-fjord 2fiddy

Full Access Member
Joined
Nov 22, 2013
Posts
210
Reaction score
1
Location
Maine
Another clue: when I went out just now I reconnected everything, and tried to trace all wires to a short/burnout spot.... Nothing. Also checked plugs near starter solenoid... all good. Buuuut... the WTS light doesn't even come on now when the key goes to run/start pos. I think maybe the accidental bridge to the "double red GPC pole" may have fried the actual GPC under the solenoid? This might explain the complete lack of 12v+ that usually goes to fuel shutoff/thermo/advance solenoid? If that GPC unit is indeed fried internally, maybe it's grounding the 12v instead of letting it flow to the other components? Yes? No?
 

laserjock

Almost there...
Supporting Member
Joined
Nov 20, 2012
Posts
8,841
Reaction score
3,129
Location
Maryland
If you just need to get it running, run a jumper from the bat to the IP on the fuel shutoff solenoid. If it starts, you've got a burnt wire or fuse or fusible link somewhere. Could have toasted the controller.
 

N.E fjord-by-fjord 2fiddy

Full Access Member
Joined
Nov 22, 2013
Posts
210
Reaction score
1
Location
Maine
I'm leaning toward the GPC unit being completely fried... Fuel shutoff- no 12v and no WTS light.

Of the two red wires runs under to the GPCs internals, and i wouldn't be surprised if the 1600 amps DC did a number on them...

I'll go try that shutoff jumper...

Honestly, I'm just going to put a dash cluster in for all of it... Switch for the fuel shutoff, switch for the elec pump, and temp push button for the GP's.

This GPC has been the bane of this trucks existence...... poor girl.
 

N.E fjord-by-fjord 2fiddy

Full Access Member
Joined
Nov 22, 2013
Posts
210
Reaction score
1
Location
Maine
Well, that jump worked my friend! Thanks a bunch. You saved me hours of testing. Now, to build the cluster box for my dash...
 

laserjock

Almost there...
Supporting Member
Joined
Nov 20, 2012
Posts
8,841
Reaction score
3,129
Location
Maryland
Glad it helped. Blind squirrel finds a nut once in a while.
 

Latest posts

Forum statistics

Threads
91,280
Posts
1,129,764
Members
24,098
Latest member
William88

Members online

Top