Burnt fusible link and bad solenoid???

[Thefarmboy21]

The last time I drove my truck, we pull started it because the batteries were dead, or so I thought...turns out the fusible link wire to the glow plug solenoid burnt in half and the started solenoid went bad because it wouldn't turn over. It's an 87 6.9 with the new style (7.3 style) wiring harness and controller. So my questions are this....

1. Did the starter solenoid short out and burn the fusible link or visa versa?
2. Where do I get or what do I use to replace whatever I need to re wire my glow plug controller to work properly. I've never seen anything other than inline fuse buses at auto parts stores???
3. Should my glow plug controller still be ok?
4. Where can I get an injector seat tool?

I really like my truck but it's been a nightmare from day one. It sat for almost 10 years before I put a different motor in it and between the mice and just sitting everything has made this truck a 3 year ordeal that still has all kinds of issues. And I am bound and determined that it's going to be my daily driver before summer is over. ***Also where's the best place to get new return line caps and seals? I plan to put clear line on all of them because I think I'm getting air in the lines which in turn even before the wires burnt, was causing me to have to roll start the truck in order to start it??? And when/if I decide to get new injectors, will I need a whole new set of return caps etc? Thanks.

 

[tbrumm]

You will to contact Conestoga Diesel in PA. Mel Agne, the owner, is a major contributor to this forum (member name "agnem") and builds the famous " Moose" injector pumps for our trucks, He will have the return line kit you are looking for. Occasionally, injector seat tools come up for bid on eBay, but many people clean the bores with a 12 gauge shotgun brush. Mel might be able to help you out with seat tool as well. As for your electrical problems, I am sure others will post soon to help you with that.

 

[madpogue]

When a fusible link burns, it opens the circuit. It's typically a device on that circuit that fails, which in turns burns the fusible link. So most likely, the GP relay shorted in some way that drew too much current, which burned out the fusible links. IIRC, there should be two parallel fusible links providing always-on power to the relay. Of course, it's also possible that a wiring problem between the relay and the GPs themselves, or an issue with the GPs themselves, is what cause the excess current draw, which burned out both the relay and the fusible links.

 

[Thefarmboy21]

Both fusible link wires burned about 4" and I'm not sure about the GP controller but the STARTER relay is what isn't working. I have to cross the terminals for it to crank.....and it of course doesn't start :/

 

[79jasper]

Eh, make your own harness or buy one.

Sent from my SM-G900R4 using Tapatalk

 

[madpogue]

Okay, the two failures are probably unrelated, then. The fusible links, all the main power wires connected to the starter relay, don't actually use any of the relay's circuitry. They just use that terminal on the relay as a junction point to connect all those wires.

One final check on the starter relay - rather than jumping the two big terminals, run a jumper wire from the battery +ve to the SMALL terminal (the one with the single wire that you just pull off) on the relay. If the truck starts, or the starter cranks, the relay is GOOD, and for some other reason, you're not getting a good power feed from the ignition switch.

 

[Thefarmboy21]

Ok so neither problem would have cause the other? Because they happened at the same time as far as I know....unless they both went bad sitting for a few months. But I don't think so. Also on the fusible link wires....when I noticed the were burnt I touched them together again and they immediately burnt off even farther. Could my glow plug controller and/or relay be bad and causing it? Can I just do away with it somehow? Like a push button or do I still need the controller for that?

 

[79jasper]

Nope, just a relay.
And obviously a huge short somewhere. Replace the wire.

Sent from my SM-G900R4 using Tapatalk

 

[madpogue]

Ok so neither problem would have cause the other?

First you have to confirm a bad starter relay with the above test. Jumping the relay and starting the truck does NOT necessarily mean the relay is bad. It's possible that there's yet another fusible link blown, so there's no power to the starter circuit going through the ignition switch. The above-mentioned test will help determine that.

sitting for a few months

Good chance mice chewed one or more wires, and some hot bare wire is touching something causing a dead short as mentioned above.

Can I just do away with it somehow? Like a push button or do I still need the controller for that?

You can bypass the controller with a manual switch, but you can't bypass the relay. You wouldn't want a switch that carries as much current as the GPs themselves. Besides, that doesn't get to the root cause.

You need to find that short. Disconnect the fusible link wire(s) at the always-hot big terminal on the GP relay. Then re-connect what's left to the junction point on the starter relay. If they burn again, the short is between that junction point and the relay. If not, then disconnect the wire(s) from the other big terminal on the GP relay, and reconnect the fusible link wire(s). See if they start to burn again. If so, then the relay is bad. If not, then there's a short between the relay and one or more of the glow plugs. In that case, you'd want to disconnect all the glow plugs, reconnect the supply and then connect each GP one by one, to see if one of them causes the short. But my money's on the relay.

 

[Thefarmboy21]

Ok, guess I've got a lot of testing to do. What can I use for the fusible link wire to check it AND then replace it when I find the problem? Mine are burnt really bad. And where's the best place to get a new relay?