Smoking Ground Wire

[454_SquarED]

My 87 running like a top after a new Coolant Temp Sensor and TV cable adjustment. Just when I say to myself, Self...this thing is running goooooood, I put my left blinker on, get into the left turn lane, after sitting for about 10 seconds waiting for traffic to clear the truck dies. Try to restart and there is barely enough power to turn the starter...smoke coming from the hood and i see this (Pic attached).

What in the holy name of Square Body demons caused this? Some funky ground thing? I've only had the truck for a couple weeks but its been fine up to this point.

The only thing on was the blinker trying to make the left. Every time i tried to start it that wire would start burning. Tried again and started and ran fine...ONLY THING DIFFERENT is I turned off the blinker. Drove it home like a BMW owner (Not using the blinker) and no problems. I suspect some short with the blinker circuit. I noticed the voltage gauge clocks back and forth while the blinker is on. I am assuming when the blinker is on that small wire is carrying the load of the starter but I'll be damned if I can figure out why when its got a big 2 guage wire sitting right next to it grounded nicely.

Ohm meter shows little to no resistance across the burnt wire to its grounding point.

Any ideas?

 

[AuroraGirl]

My 87 running like a top after a new Coolant Temp Sensor and TV cable adjustment. Just when I say to myself, Self...this thing is running goooooood, I put my left blinker on, get into the left turn lane, after sitting for about 10 seconds waiting for traffic to clear the truck dies. Try to restart and there is barely enough power to turn the starter...smoke coming from the hood and i see this (Pic attached).

What in the holy name of Square Body demons caused this? Some funky ground thing? I've only had the truck for a couple weeks but its been fine up to this point.

The only thing on was the blinker trying to make the left. Every time i tried to start it that wire would start burning. Tried again and started and ran fine...ONLY THING DIFFERENT is I turned off the blinker. Drove it home like a BMW owner (Not using the blinker) and no problems. I suspect some short with the blinker circuit. I noticed the voltage gauge clocks back and forth while the blinker is on. I am assuming when the blinker is on that small wire is carrying the load of the starter but I'll be damned if I can figure out why when its got a big 2 guage wire sitting right next to it grounded nicely.

Ohm meter shows little to no resistance across the burnt wire to its grounding point.

Any ideas?

you need to shore up the grounds. Heads to the firewall. frame to core support. Engine to battery. core support to battery.

 

[Scott91370]

And a new one from the battery to everything.

 

[TotalyHucked]

Don't forget each place the harness grounds. The front lights ground to the core support on each side.

 

[Truck82]

My 87 running like a top after a new Coolant Temp Sensor and TV cable adjustment. Just when I say to myself, Self...this thing is running goooooood, I put my left blinker on, get into the left turn lane, after sitting for about 10 seconds waiting for traffic to clear the truck dies. Try to restart and there is barely enough power to turn the starter...smoke coming from the hood and i see this (Pic attached).

What in the holy name of Square Body demons caused this? Some funky ground thing? I've only had the truck for a couple weeks but its been fine up to this point.

The only thing on was the blinker trying to make the left. Every time i tried to start it that wire would start burning. Tried again and started and ran fine...ONLY THING DIFFERENT is I turned off the blinker. Drove it home like a BMW owner (Not using the blinker) and no problems. I suspect some short with the blinker circuit. I noticed the voltage gauge clocks back and forth while the blinker is on. I am assuming when the blinker is on that small wire is carrying the load of the starter but I'll be damned if I can figure out why when its got a big 2 guage wire sitting right next to it grounded nicely.

Ohm meter shows little to no resistance across the burnt wire to its grounding point.

Any ideas?

What does the ohm meter show exactly? There should be about 0.1 ohms of resistance with absolutely no current running through the circuit. Isolate the wire when reading ohms.

 

[Matt69olds]

I bet you will find either a loose ground wire, or bad corrosion inside the insulation of the heavy ground wire.

Since the main ground wire is compromised, the smaller ground wire is trying to pick up the slack. The starter is pulling far more current than the wire can handle, causing the internal smoke to vacate. Everyone knows smoke is what makes electrical things work. Once the smoke is let out, electrical stuff stops functioning!!

 

[75gmck25]

Start with the dash cluster. There should be a black ground wire up high under the dash. On an '87 I think there is a ground bus it connects to on the firewall, and older trucks the ground is a post on the top of the emergency brake.

Then make sure the large 2 gauge ground wire on the battery connects to the alternator bracket or some other substantial part of the engine. Use a wire brush and/or sandpaper to clean down to bare metal, and make sure it's really grounded well. The battery end of it should also have a smaller wire molded on, and it will connect to a ground point on the radiator support. There should also be a ground on the back of the engine on the passenger side, running over to the firewall, and thick braided ground from the engine over to the frame rail on the passenger side.

Also take out the front turn signals and make sure each one has a ground wire, and then clean off the rust where its screwed into the body and reground each light.

In the back of the truck right above the point where you would have a trailer hitch, there should be a white ground wire for the rear light harness, and it should be grounded to the frame.

There may be a couple more ground points on an '87 since it has fuel injection and more electrical devices than the older trucks.

 

[AuroraGirl]

Start with the dash cluster. There should be a black ground wire up high under the dash. On an '87 I think there is a ground bus it connects to on the firewall, and older trucks the ground is a post on the top of the emergency brake.

Then make sure the large 2 gauge ground wire on the battery connects to the alternator bracket or some other substantial part of the engine. Use a wire brush and/or sandpaper to clean down to bare metal, and make sure it's really grounded well. The battery end of it should also have a smaller wire molded on, and it will connect to a ground point on the radiator support. There should also be a ground on the back of the engine on the passenger side, running over to the firewall, and thick braided ground from the engine over to the frame rail on the passenger side.

Also take out the front turn signals and make sure each one has a ground wire, and then clean off the rust where its screwed into the body and reground each light.

In the back of the truck right above the point where you would have a trailer hitch, there should be a white ground wire for the rear light harness, and it should be grounded to the frame.

There may be a couple more ground points on an '87 since it has fuel injection and more electrical devices than the older trucks.

the poor decision to use the thermostat housing to ground the PCM and run the engine ground was a poor choice