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Auxilary ground wire smoking...ugh

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OK, so on a cold day/cold start the Jeep takes a few cranks to get started...well, sometimes a lot of cranks (choke issue, different subject on that later). However, on the elongated cranking startups I have an auxiliary ground wire coming off top of NEG terminal to firewall (top arrow) that has started SMOKING, no Bueno. I have the standard large gauge ground to the engine block (bottom arrow).

My thought is, electricity will travel path of least resistance and the whole thing is trying to ground to the firewall?! Auxiliary ground not installed by me, but assuming was installed when auxiliary power for original dealer installed AC was done...as it has an auxiliary power to POS terminal.

Now, do I need the auxiliary ground or is just short circuiting the whole system?! I'm thinking I can just remove the thing and no loss since it all grounds through the large gauge wire to the engine block right?

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If that big fat red wire pointed out by the bottom arrow is going to the engine block, you're lucky it hasn't gone up in flames. :LOL:

Do you have a ground strap on your engine (from the block to the frame)? If the engine's not grounded to the frame, then the big fat ground wire is only grounding the engine to the battery, and your skinnier firewall ground wire is bearing the brunt of entire grounding effort - which could be why it's smoking (the engine being isolated by the motor mounts, and all). If you pop a ground strap from the engine to the frame, that should do it.
 

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The big ground wire should be going from the battery directly to one of the starter mounting bolts. The biggest load is the starter, so that is were the biggest ground should be. There should also be a ground strap from the engine to the frame to bridge the engine mount. Then secondary grounds to the body and whatever.
 

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Discussion Starter · #5 ·
Are you talking that little black wire with something yellow attached to it?

You might need a bigger boat 'er wire
Yes, that is the wire.

If that big fat red wire pointed out by the bottom arrow is going to the engine block, you're lucky it hasn't gone up in flames. :LOL:

Do you have a ground strap on your engine (from the block to the frame)? If the engine's not grounded to the frame, then the big fat ground wire is only grounding the engine to the battery, and your skinnier firewall ground wire is bearing the brunt of entire grounding effort - which could be why it's smoking (the engine being isolated by the motor mounts, and all). If you pop a ground strap from the engine to the frame, that should do it.
Yes, if red wire were grounded we'd be up in flames! Lol. Sorry should've been more clear, the lower wire is pointing to the attachment point of the NEG battery ground to the block. Block is strapped to frame on drivers side around engine mount (see new attachments):
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Back to original question; is the "little black wire with something yellow attached to it" necessary or can I just remove it altogether? Don't mind replacing it with a larger/newer one, but if it is just circumventing the main ground then why replace and not just remove?!

Thanks for the insight guys.
 

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Well if it’s smoking it means that it’s the ground for everything else like mister4x4 said. You got headlight, tail lights, blower motor, radio,wiper all going thru that little wire.
I think the original ground for the body was a flat braided cable. Something that can handle lots of current. Probably at least a 6ga wire or bigger.
 

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One of the first things I did when I got my CJ was to replace the main red / black battery cables to 2 gauge through the solenoid to the starter and to the block.

That bottom block to frame cable was swapped to a new 2/0 cable.

Mine also has the little ground pigtail from the battery to the firewall.

On mine, all connections are clean and tight.

My preference is for only a single wire on the battery terminals. All supplementary connections are made elsewhere.
 

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Discussion Starter · #8 ·
Right...and thanks. Confirms my thoughts; I'm gonna yank the sucker...ensure that everything is functional in ON position (engine off) then crank her over and recheck everything (with engine running). If it comes down to it I've got a section of 4ga leftover from winch install laying around and will throw that on there.

Stay tuned 😵‍💫, lol.
 

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OK, so on a cold day/cold start the Jeep takes a few cranks to get started...well, sometimes a lot of cranks (choke issue, different subject on that later). However, on the elongated cranking startups I have an auxiliary ground wire coming off top of NEG terminal to firewall (top arrow) that has started SMOKING, no Bueno. I have the standard large gauge ground to the engine block (bottom arrow).

My thought is, electricity will travel path of least resistance and the whole thing is trying to ground to the firewall?! Auxiliary ground not installed by me, but assuming was installed when auxiliary power for original dealer installed AC was done...as it has an auxiliary power to POS terminal.

Now, do I need the auxiliary ground or is just short circuiting the whole system?! I'm thinking I can just remove the thing and no loss since it all grounds through the large gauge wire to the engine block right?

View attachment 4166721
Uh.u wouldn't be a fireman by chance..
That heavy guage wire (red)
Point to by arrow is on positive post..
It should not go anywhere but to an
Battery isolator, or auxiliary fuse/breaker buss..such as for lighting. If it is going to firewall
You have a high current short to ground..thru a high resistance point
.which will get very hot...like a hot dog roast..
OK, so on a cold day/cold start the Jeep takes a few cranks to get started...well, sometimes a lot of cranks (choke issue, different subject on that later). However, on the elongated cranking startups I have an auxiliary ground wire coming off top of NEG terminal to firewall (top arrow) that has started SMOKING, no Bueno. I have the standard large gauge ground to the engine block (bottom arrow).

My thought is, electricity will travel path of least resistance and the whole thing is trying to ground to the firewall?! Auxiliary ground not installed by me, but assuming was installed when auxiliary power for original dealer installed AC was done...as it has an auxiliary power to POS terminal.

Now, do I need the auxiliary ground or is just short circuiting the whole system?! I'm thinking I can just remove the thing and no loss since it all grounds through the large gauge wire to the engine block right?

View attachment 4166721
If that red wire is not grounded..
But the second black ground is..to the firewall..two resistances in parallel, in this case the black grounds. Will more than halve the the resistance, so the starting current is going to flow thru the wire and the high resistance point
Getting very hot.
 

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Unhook the one going to the firewall.
What is your result..primary ground now smoking? Yes ,No?
That large of a current wire should never be grounded to the firewall.
It should going to th original frame
Ground point,otherwise you create
Wweird, fire causing ground loops,
Called a daisy chain.
 

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Discussion Starter · #12 ·
Unhook the one going to the firewall.
What is your result..primary ground now smoking? Yes ,No?
That large of a current wire should never be grounded to the firewall.
It should going to th original frame
Ground point,otherwise you create
Wweird, fire causing ground loops,
Called a daisy chain.
Thanks for the insight/thoughts; I was unclear on the original post and tried to clear it up on subsequent post. Large gauge red/pos wire is not grounded; large black/neg wire is grounded to block (which is strap grounded to frame). The "auxiliary ground" small gauge wire from neg battery terminal to firewall is one in question/smoking on hard starts.

I agree with unhooking it and see what happens as I believe everything is trying to ground through it and not the block/frame route, but can also replace it with a larger gauge wire if needed for some unforseen reason.
 

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The comments about your red wires are about harness protection.

As built there was a short length of red wire from battery to solenoid and from solenoid to starter. This was unfused and unprotected. Given the high loads it was impractical to put in fusible links.

All other harness circuits were protected by the fusible links A and B at the starter solenoid. These are not going to blow when your radio shorts but will if your harness is in danger of melting and a vehicle fire is about to start. One common places for harness fires is inside the firewall where wires can rub.

So the comment is whether you have some protection for that second red wire. Does it have a maxi fuse or go through a fuse box or have a fusible link of its own? How safe is it from shorting?

Schematic Font Parallel Engineering Plan
 

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Unhook the one going to the firewall.
What is your result..primary ground now smoking? Yes ,No?
That large of a current wire should never be grounded to the firewall.
It should going to th original frame
Ground point,otherwise you create
Wweird, fire causing ground loops,
Called a daisy chain.
Any aux power buss, or winch,lighting
Ground, should endeavour to put that particular buss/circuit ground on the same frame rail as battery ground.
 

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If that aux ground to firewall is getting hot on long cranking cycles, check to see if your primary ground from bat is routed to starter mounting bolt.the starter draws the most current in system.disconnect the primary ground from bat post..take volt ohm meter and check to see if the primary is either intermittent open or open..I would suspect all the starter current draw is going thru the aux ground, gets hot under long loads..By experience I do take the firewall ground off the same starter mount bolt. That supplies a common ground point
 

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If that aux ground to firewall is getting hot on long cranking cycles, check to see if your primary ground from bat is routed to starter mounting bolt.the starter draws the most current in system.disconnect the primary ground from bat post..take volt ohm meter and check to see if the primary is either intermittent open or open..I would suspect all the starter current draw is going thru the aux ground, gets hot under long loads..By experience I do take the firewall ground off the same starter mount bolt. That supplies a common ground point
It's good to see that grounding strap from the enging to the frame. in the picture.It's critical for a number of reasons. On the electronic engines, ECM/PCM,etc., a mishmash of multiple grounds can incur voltage and current spikes that electronics don't agree with. Especially with radios/audio with high current drawing audio amps. Addendum: If you need a CB set or Ham radio onboard, you would repeat that grounding strap along the frame from the body. That allows RF current to flow both over the body and the frame, acting as a slightly raised ground plane above the surface of the road. If a shunt coil is added to the coax/antenna connection, it brings the antenna impedance into 50 ohm range for closer matching. So, that grounding strap has critical function. Lowering resistance and creating low résistance path to starter circuit.
 

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I read them and as always confused by wiring diagram. My cherokee, 01, started acting oddly electrical at a gas station. I got it running and watched voltage gauge and speedo bounce from 0 to max then it seemed to be ok. About 1/4 mile from entry gate all went dark and it landed on drivers side. I am fairly sure that was from lower than expected voltage to ancillary devices, lights, gauges and computer box(es). They don't handle that at all well. I was not able to check for hot wires between the time it happened and following morning picking it up to set on wheels with a backhoe. A new battery with cleaned terminal cables down into insulation has seemed to fix.
 

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Pull the ground off the block. Is that spot painted, rusty, etc? Clean to shiny metal, and reattach. Better yet, use a starter mounting bolt to hold it tight to the starter body. Any paint between starter and block will cause resistance.

On older Freightliners, you always knew when the main frame-to-block ground cable was bad when the power steering pressure line started cooking when cranking the engine. Electricity follows the path of least resistance, and if it's using that little wire to ground when starting, you need better grounding.

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