Truck died yesterday.

[phazertwo]

So I was up in the hills playing on the dirt bikes, and the truck ran kinda weird on the way up. When you let off the skinny pedal in N it took to long for the RPMS to come down. When you let off the skinny pedal in gear the truck just kept going (it has done this for a few months when its cold and the fast idle and timing advance are on) We made it to my friends house and rode bikes for a few hours, than came back to look at the truck. I decided to un-plug the high idle and timing advance, and all was well. We loaded the bikes, and went inside for some dinner and . However after dinner we deiced to head out but the truck would not start. Turned the key on and the WTS light flashed on than right back off. I figured my GPR finally finished itself off, but it had been running 2 hours ago and it should be fine to start. It turned over great, but didn't even try to fire. No diesel smell out of the tail pipe like if the GPs were not working. So I check for 12v at the fuel shut off on the IP with the key on. No go. Since it was late I just jump the fuel shut off to the battery and drove it home. While I was trouble shooting this I tried every fuse on the truck, all good.

Any ideas??

Anyone have the wiring diagram for the ignition switch, to the GPR and the fuel shutoff on the IP?

TIA
PZ

 

[towcat]

sounds like the injection pump went looking for it's fork.
loosen the line nuts and crank it over. if there's no fuel, your pump is done.
but maybe on the outside chance your fuel shutoff solenoid bit it, but I really doubt it.

 

[phazertwo]

sounds like the injection pump went looking for it's fork.
loosen the line nuts and crank it over. if there's no fuel, your pump is done.
but maybe on the outside chance your fuel shutoff solenoid bit it, but I really doubt it.

I jumped the fuel shutoff and drove it home. Problem is in the wiring, the shutoff is not getting 12v when the key is on.

PZ

 

[towcat]

I jumped the fuel shutoff and drove it home. Problem is in the wiring, the shutoff is not getting 12v when the key is on.

PZ

there's a fusible link on the body side of engine harness. follow the wire color from the FSS and back through the connector.

 

[86ford69]

Mine did the same thing and I never did get it right. I traced wires for days and hooked it back up to where it came from but no luck. I just ended up putting in a toggle switch. Good luck brother.

 

[jim x 3]

Anyone have the wiring diagram for the ignition switch, to the GPR and the fuel shut of on the IP?

TIA
PZ

Phaser, This diagram is good for 1988, supposedly good to 1994.

Good luck,

 

[phazertwo]

PhaZer, This diagram is good for 1988, supposedly good to 1994.

Good luck,

Looks like they are different.

I found this.

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Looks like I need to chase my red/light green wire (the one that goes to the FSS). I will have to check the fusible link first, but I am guessing that the problem may be in the ignition switch itself...


Towcat: Do you know abouts where the link is? I can find the on that feeds the GPR but nothing on the FSS wires (red/light green). Looking at the diagram it doesn't look like the 93's have a fusible link on the FSS, just on the GPR.

PZ

 

[jim x 3]

Phaser:

Yeah, all of those diagrams are slightly different. Looks like fusible links aren't at issue for 1993 model.

You're on the right track. If your glow system and FSS aren't energized with KOEO, then its fuse K, the red/lt grn wiring, or the ignition switch. I would suspect the ignition switch. But if you have +12v @ the fuel heater with KOEO, maybe your GPC (or wiring) blew fuse K. A maxi fuse looks the same as a regular blade fuse, but its about twice as big. If its 20A, it should be yellow. It may be co-located with fuse U.

Good luck,

 

[phazertwo]

PhaZer:

Yeah, all of those diagrams are slightly different. Looks like fusible links aren't at issue for 1993 model.

You're on the right track. If your glow system and FSS aren't energized with KOEO, then its fuse K, the red/lt grn wiring, or the ignition switch. I would suspect the ignition switch. But if you have +12v @ the fuel heater with KOEO, maybe your GPC (or wiring) blew fuse K. A maxi fuse looks the same as a regular blade fuse, but its about twice as big. If its 20A, it should be yellow. It may be co-located with fuse U.

Good luck,

I am familiar with maxi fuses. I have checke all the fuses in the entire truck, so I am thinking my ignition switch took a dump. Funny because it will still run the starter, and it will still run everything else in the on position, just not that one circuit.

PZ

 

[johnnyb1]

It may be nothing but I had an 88 and got a recall on the ignition switch. Yours is newer but that's the first thing I thought of.

 

[MidnightBlade]

By the looks of the diagram for the 93, your red/lt green wire runs into the GPC. I don't know if it is wired into it or if it is just connected there, but could the GPC taking a crap cuase that wire to be dead?

If that could happen then the next thing in line is your FSS and that would be the problem. And then again the problem could be I don't have the truck in front of me to see the GPC and see if the wire is run into it or just beside it.

 

[phazertwo]

So I spent two hours on it tonight. All I figured out is that the red/ltgrn is shorted to ground. So if I touch the fuel shut off switch terminal on the IP and the ground battery post, I get continuity. From the looks of the diagram that would be incorrect. However I cannot find any where where that circuit grounds.

PZ

 

[phazertwo]

So I spent two hours on it tonight. All I figured out is that the red/ltgrn is shorted to ground. So if I touch the fuel shut off switch terminal on the IP and the ground battery post, I get continuity. From the looks of the diagram that would be incorrect. However I cannot find any where where that circuit grounds.

PZ

 

[phazertwo]

Can anyone take a minute and check continuity to ground on their FSS on a OBS truck? I really wanna get this bad boy back in action!!

PZ

 

[phazertwo]

Anyone?