Junction block wire started smoking when try to start?

[Tdouble]

1988 V10 Suburban's been starting and running great, went out to start it yesterday and wire at junction box started smoking.no power or sound from starter. It's the smaller of the 3 wires on passenger side of junction box with a fusible link, the larger one has a fuse inline. This one runs down into a wiring conduit that goes behind the engine towards passenger side and dissappear. Am trying to figure out if it's a wire to my alternator or starter but is to tight to follow it and to dirty/old to tell what color.
I'm figuring it's gotta be a short somewhere, or could it be my starter locked up and causing the burning of the wire? Thank you for any help.

 

[Chevy 88]

Your main power wire goes strait from the battery to the starter, so you know that's not sorted. There is a wire that basically goes from the key to the starter (a few twists and turns aside), and when you try to start the engine, that wire becomes electrified. That's what signals the starter to... start.

So if that wire is shorted (insulation melted, shorting out on the exhaust), then something is going to smoke or burn out when you try to crank it.

So you want to take the keys out of the ignition, and then use a volt meter on the starter to check for continuity between the starter signal wire and ground.

That will confirm that the wire is either shorted or not.

In the mean time, you can still use the truck by jumping the starter with a screwdriver until you get it fixed.

 

[75gmck25]

Sounds like the wire running from the ignition switch to the starter solenoid. It runs over from the fuse block area to the back of the engine, and then down through a protective metal tube to the starter terminal.

 

[Old Guy Bill]

“Fusible Link” it’s a section of the factory wiring that is designed to do exactly what it did…
Possibly the starter/solenoid has some type of problem causing a high current draw.
The “Fusible Link” should be replaced when the problem is corrected.

 

[75gmck25]

If you crawl under the truck and clean off the wiring terminals on the starter, one of them is the S terminal (solenoid). It may be the only one that has a single wire on the small terminal.

Disconnect the wire running to the S terminal. Then if you jump/touch a short wire from the S terminal to the lug where the main battery cable connects, the starter should turn over. If it does not turn, or you get more smoke, then you have a starter issue (short, etc.). This means replacing the starter.

If the jumper wire makes the starter work normally, the short is probably in the wire running from the solenoid terminal up to the ignition switch. It could be grounding on the metal tube, or any of several other points. You will have to find the bare spot and probably run a new wire to replace the bad section. I think it’s probably a 10 gauge wire with a 14 gauge fusible link, but I would have to verify with a wiring diagram for your truck.

 

[Tdouble]

Jumped the starter now no power to fuel pump? Is the fuel pump same wires connecting to the junction box?

 

[Tdouble]

Fixed it!! Was a coil wire grounding out back behind Engine... Had no power to Fuel pump so when I tried to jump the starter, was a no start just turned over. Had to chase down the 4 wires coming from Junction Box.. Thank you for the responses and advice, you all are Very knowledgeable and helpful............