destroyer of ground wires

[wildbob]

Hi Folks,
Been gone and busy with military stuff, and when i got home one of the first things I did after hugging the family was... OF COURSE FIRE UP THE BUGGY DAMMIT!!! "WUrrrr-wurr-wurrr-wurrrrrrrrrr......." Oh, is my battery dead? No.. Just me melting my wiring again.... For some reason I occasionally send craploads of voltage down my ground wire.. I'm wondering if it's something loose up in my dash I built.. I checked the negative terminal on the battery to make sure that was tight.. I'll have to do and autopsy of the harness.. (BTW it fired right up after, but anything that was next to the ground wire is melted too.) Oh well, I'll have to order harness number three..

[Sickartistic]

Gotta love those damn shorts. The heat is intense I feel your pain, luckily mine was only voltage regulators cooking.

[Sickartistic]

btw thank you for serving!

[bigmurph]

Do you know how to do a voltage drop test? That will be the easiest way to find your problem.

[SYCARMS]

Also check for short to ground.

[wildbob]

Yeah, I need advice how to diagnose this, electrical systems aren't part of my skillsets I've got a multimeter and I'm not colorblind..Those are my only bonuses as far as wiring goes. The problem ONLY happens when I crank the motor, so any help would be appreciated Thanks!

[ckau]

Your getting way too much resistance somewhere in the ground circuit.
either a broken wire inside the jacket, corroded wire and/or connectors or as Tom suggested, a dead short.
what size wires are used for the ground leads? How and where are they connected to the motor case?
Seeing as this occurs in the cranking cycle I would inspect all the wiring associated with this circuit first.
If it were me I wouldn't waste time trying to trace it down I would rip out the whole ground associated system starting at the battery then replace with 10g minimum. Once these wires get hot a time or two their life span deteriorates very quickly.
Replacing the whole ground system with fresh wire will give you a permanent fix.

[SYCARMS]

ckau is correct. I never had a problem with mine until I changed my stator to a 10 pole. after the change my ground would occasionally burn up and if I run the engine hard it would blow the fuse and I would have to replace it for the next start. When my harness went bad (at least I thought for it turned out to be the stator even though all checks showed it to be good) I made my own harness using 14g wire for the harness with 10g as the heavy load wires and ground, with sealed plug ends. I have not had any trouble since.

[wildbob]

I've replaced the harness twice, so corrosion/breakage shouldn't be as issue as the wires are new. The ground is going to the engine case in the stock location. If I'm not mistaken the ground wire is part of the harness, so I've been hesitant to split it open (obviously wiring isn't my strong suit.) I made a custom aluminum dash with new switches/ignition/etc and I'm wondering if something up on that end is wrong (ignition switch?) thats flooding the ground with voltage.. All the accessories the wire into the power seem to work okay (TT Vapor, lights, indicator lights, blinkers, etc) but maybe somethings amiss..

[bigmurph]

Put your volt meter on dc volts. Take the circuit n question and check across the circuit. You could go from the battery negative post to the ground at the engine. Start the engine and observe the volunteer readings cranking. I don't think you should see over a volt. If you do, you will have to make a measurement somewhere else in the same circuit until you isolate the problem.

[wildbob]

Originally Posted by bigmurph

Put your volt meter on dc volts. Take the circuit n question and check across the circuit. You could go from the battery negative post to the ground at the engine. Start the engine and observe the volunteer readings cranking. I don't think you should see over a volt. If you do, you will have to make a measurement somewhere else in the same circuit until you isolate the problem.

One lead of the meter on the Neg terminal one lead on the ground? Just making sure i'm hearing you right..

[xlint89]

You can also add another ground wire or strap from the engine to negative post of the battery for good measure.

Might I suggest you clean your ground bolt threads and chase the threads inside the engine case to clean any debris out. And do not use any thread locker (Loctite) on it as that may be preventing you from having a good contact.

Just a quick thought. Your bolt isn't loose or stripped out is it?

[bigmurph]

Yes. Start from both ends. If voltage is high on the ground side, you will leave the battery one there and move closer to it on the other side until you measure close to zero.

[wildbob]

Originally Posted by xlint89

You can also add another ground wire or strap from the engine to negative post of the battery for good measure.

Might I suggest you clean your ground bolt threads and chase the threads inside the engine case to clean any debris out. And do not use any thread locker (Loctite) on it as that may be preventing you from having a good contact.

Just a quick thought. Your bolt isn't loose or stripped out is it?

Ok, I'll check the bolts but they should be ok. I Like the additional connection idea. I'll also check that the Battery Tender connections that sit between the battery and the harness aren't cruddy and causing problems.

[wildbob]

Originally Posted by bigmurph

Yes. Start from both ends. If voltage is high on the ground side, you will leave the battery one there and move closer to it on the other side until you measure close to zero.

Roger that, I'll check that too.

[wildbob]

Originally Posted by SYCARMS

ckau is correct. I never had a problem with mine until I changed my stator to a 10 pole. after the change my ground would occasionally burn up and if I run the engine hard it would blow the fuse and I would have to replace it for the next start. When my harness went bad (at least I thought for it turned out to be the stator even though all checks showed it to be good) I made my own harness using 14g wire for the harness with 10g as the heavy load wires and ground, with sealed plug ends. I have not had any trouble since.

Awesome. I'll dissect the old harness to see how it's wired and maybe build a new one with beefier wires. The section of the harness than runs forward to the dash seems to be fine, but I'm rough on my buggy so I'll double check that something up there hasn't come loose too.

[wildbob]

Originally Posted by Sickartistic

btw thank you for serving!

Your Welcome!! 'Murica!

[xlint89]

Originally Posted by wildbob

Your Welcome!! 'Murica!

Thank you for your service, and also thanks for the laugh.

[wildbob]

So I dissected the 1st harness back to the point where all the ground wires connect together and the one to the engine case looks like the only one that heated up (besides the ones that were in close proximity)

[SYCARMS]

Run a braided ground strap from engine to engine carrier.

[wildbob]

Cool, hopefully the harness that's on it now can be salvaged with a new main ground. The one i took apart melted it's neighbors and is beyond hope. I'll probably get a new one and beef up the grounding on that one too..