Have a 2000 F350 7.3L, Problem is the glow plug relay to the fusible links keep frying. I have checked the Ground terminals at the engine block and both are nice and tight. First set i replaced literally caught on fire. Just replace the GPR with one from Oreillys as the other one was partially melted. Using the 12Gauge fusible links from NAPA. Luckily it came in the 5 foot roll. Might need all of it before this is figured out. If anyone can help it would be greatly appreciated.

 

Have you checked you Glow Plugs? Here's a couple of prints for ya

 

Yes i just replaced the glow plugs and i am getting the correct OHMs. Everytime i go to even place the new links on the starter solenoid it sparks, when i tried to take replace them with the batter terminals disconnected, once i connected the terminals back to the batteries, the wires melted and caught fire.

 

Ok I would check the lead going to the GPR & the IAH (Intake Air Heater)relay for a short to ground ( Black/Orange wire) see if it is rubbing any were and has rubbed the insolation off the wire.

 

Richard,
I will check again, maybe i missed something there. Thanks for your help and i will let you know if i find anything out of the ordinary with the wires.
Russ

 

Ok sounds good, and BTW Welcome to FTE

 

Thanks for the welcome

 

I think B+ wire on the back of the alternator is on that same fusible link as well

 

Okay went home last night spent about 3-4 hours going through the darn thing looking for something that would tip me off. Again replaced the GPR last night, replaced a randon 30 Watt Buss Fuse, and checked every wire going from the starter solenoid to the GPR, The Intake Air Heater and back to the Alternators. Bought new Motorcraft Plugs to replace the ones which are in there. Still cannot figure out why it is still sparking and catching fire everytime i place the main GPR fusible links to the starter solenoid. There are 2 other sets of fusible links connected to the starter solenoiod but neither of those are having any problems so that should isolate the short. But i dont know where else to look. If the glow plugs were bad on either side of the engine, would it cause this? Thanks for all your help guys, this has pretty well got me baffled.

 

No, the glow plugs are not powered until the GPR is closed. If the links are burning out as soon as you connect power to them, then there has to be a short somewhere between the stater solenoid, and the glowplug relay. Now if it is burning the links after you turn the key on and the GPR closes then i could possibly see a short under the vavle cover, but you said you ohmed that out and all readings were in spec. There has got to be a chafed wire in the bundle somewhere that is causing the short.

 

I would disconnect the lead from the AIH to the AIH heater element to rule that out. I believe Brendan (Papadelogan) had a ground problem at the AIH element that was frying the fuseable links.

 

Okay so I didnt mention this before, and i am not sure if this brings anything else into play, but i am running the dual alternator system (ambulance package) not sure if this could cause more headache to it.
I took the wires out of the sheaths last night and ran them all the way back to the GPR. Now i did find that the wires coming from the top alternator going around the GRP and the AIH were spliced together with that wire coming out to the solenoid with the fusible link. It was all originall ford wrap and seal.
So i will need to unhook the lead wire to the AIH then try the fusible links again, got it. i will try this and see what happens.
Again thanks for all the help. Well i will say one thing, all this is a great learning experience

 

Here is a Power Distribution Print, shows the fusible links going to the GPR,AIH and Alternators. I would start at the Alternators and remove the wire there first then work my way back.

 

Deluxe06,
Thanks for the diagram. As far as starting from tthe alternator back i did that last night. Took all the wires out and checked them for any signs of burns or scrapes. Everything was fine. I will check again tonight and post the results. Hopefully happy ones, but im not too optimistic at this point.

 

I guess I worded(wow were that come from)it wrong, what I was trying to say is pull the wires off the alternators(one at a time) then try hooking up the link to see if it arks. When it does'nt you will have located a point of interest. Do this all the way back to the starter solenoid.