Ground wire catches fire - Team Camaro Tech
Electrical & Wiring Troubleshooting electrical.

 
LinkBack Thread Tools Display Modes
post #1 of 15 (permalink) Old Aug 20th, 09, 09:03 PM Thread Starter
Senior Tech
Lex
 
Lexlas's Avatar
 
Join Date: Jun 2009
Location: California
Posts: 1,279
Ground wire catches fire

Well i gotta say problems with my camaro are like a curse so far, i've owned it four months or so. I just had a new engine put in and i am suppose to put in 500 miles asap, street driving. I have been driving it and it's been ok. Yesterday it would not start in my garage ? Why, i don't know. I checked some of the wiring after i checked the battery and some were rusted and i cleaned them up cut and re did them nicely to make a good contact and it started great. Maybe it started because i moved them around ? The thing is today it started perfectly i drove it for 10 minutes or less and stopped at a local park. i got ready to go and again it would not start ? WTF ? so i checked under the hood and one of the wires on the firewall started to heat up extremely hot and then it was disolving itself and smoke everywhere from this thin wire ! Holy crap ! i disconnected the battery right away by turning the kill switch to the off position and it stopped. I had to get it towed home. I followed that wire frome a behind the headlight somewhere and it goes all the way to the starter. Why did it get hot and catch fire ? Any one know ? I will tow it back to the shop tomorrow and see if they wired something incorrectly when they put in my new engine. I will take pix when it's day time. That wire by the way was covered in black tape all the way along the firewall, strange ?


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


68 Camaro / 400 ci / 3.73 10 /
Edelbrock Performer Series 600 cfm no. 14054
Edelbrock Performer EPS Intake Manifold 27014

98 GMC Suburban / 454 V8 / K2500 4x4

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Lexlas is offline  
Sponsored Links
Advertisement
 
post #2 of 15 (permalink) Old Aug 20th, 09, 09:34 PM
Super Moderator
Bess-68's rule
 
Everett#2390's Avatar
 
Join Date: Sep 2000
Location: Va Beach VA
Posts: 31,670
Garage
Re: Ground wire catches fire

Good thing a kill switch is installed. Good quick decision making.

This wire you describe, from the headlight area, OE design = Pass side is a junction block connecting battery positive pigtail with red wire across rad support to horn relay buss bar. OE alternator hookup has a red wire crimped with another red wire from horn relay to dash to headlight switch and on through electrical system from there.

If an internal reg alt is added, previous owner(s) may have ran a large wire from starter solenoid post to this junction block to charge battery. If solenoid stuck in ON position and starter drive jammed into flywheel ring gear and kept starter engaged and with starter motor not turning, lots of current is being transferred. This action is called 'locked rotor' test and gobs of current is drawn, until cable melts.

Without pictures, hard to suggest other possibilites. When you went to start the engine at the park, you would have heard a 'clunk' and no return of solenoid when key was released, starter jammed.

Hope damage wasn't too bad. As I said, I can only speculate. From the alt shown, the heavy gauge wire from BAT terminal is routed to _______? The two wire plug on the alt, is it 'll' or '- -'?

Give a man a rescued dog for the health of both their souls. May 2017 ROTM Winner - Thank you!
'
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
CUBS - 2016 World Series Champions - Thank you, Joe Madden Ö enjoy your next chapter.
Everett#2390 is offline  
post #3 of 15 (permalink) Old Aug 20th, 09, 10:25 PM
Gold Lifetime Member
Lane
 
Join Date: Feb 2002
Location: Livermore, CA USA
Posts: 1,157
Re: Ground wire catches fire

Wow Professor Everett hadn't heard locked rotor current in awhile....

I installed an aftermarket ammeter in my 67 in high skool..used too small of guage wire..it did the same thing..and runs a similar path.

Perhaps it was patched and needs to be replaced with heavier wire..whatever it is??
67 RSS is offline  
 
post #4 of 15 (permalink) Old Aug 20th, 09, 10:41 PM
Senior Tech
Sean
 
Join Date: Feb 2002
Location: N.W. Washington
Posts: 7,962
Re: Ground wire catches fire

"Locked rotor", I have to consider this everytime I do a motor load calc at work , don't see it used with cars much but Everetts' right, that would do it.
It's got to be a dead short pretty much for that to happen, either through a stuck switch to something thats not working like a motor, or with that wire since it runs in a pretty ugly environment with heat and sharp edges, it may have gone to ground at some point on the body or motor, follow it from the point it burnt all the way to it's point of termination. Was the ignition still in the 'on' position?

Whats odd to me is why is that wire going from the block behind the battery to the starter? Are they picking up main power from down at the starter for the terminal block? It should come right off the battery to that block, and from the block to the horn relay and all the rest of the accessories right?
At the starter you should just have 1 or possibly 2 small wires, and the large battery wire. The purple (or whatever color by now) should be the ignition, and the other wire if still there should go to the pos side of the coil.
Sounds to me like you need to track that guy down, who knows where it goes and what a previous owner did, the black tape all over it raises flags to me. Let us know what you find.
Don't get frustrated, you'll get it and it will be worth it!

Sean

1968 rs with an old school 354" SB2.2 pump gas motor.

Repetition does not transform a lie into a truth.

Franklin D. Roosevelt
68rs406 is offline  
post #5 of 15 (permalink) Old Aug 21st, 09, 04:15 AM
Moderator
Kevin
 
KevinW's Avatar
 
Join Date: Jul 2000
Location: Millstone, NJ
Posts: 11,048
Re: Ground wire catches fire

Something is not right here. I have been rebuilding all my 69 harnesses, taillight to headlight, so I have been "into" the inner workings of these lately.

First, the factory wrapped the engine harnesses in non-adhesive tape. If the tape is gooey "electrical" tape, then it is an later add-on.

The firewall harness is seperate from the headlight harness. There should be NO wires that go from "behind the headlight" to the starter from the factory. Both of those harnesses go into the fuse panel seperately. The path of electricity does jump from Batt harness to starter harness, but it goes through the ignition switches under the dash first.

If a wire goes up in smoke, then you have a short, plain and simple. A short can also be a wire that had insulation exposed to a 12v of a higher amp rating that then runs down the wire and exceeds is rated capacity and the insulation cooks. Finding the short is the fun part.

These 40 year old harnesses with previous owner's "improvements" are dangerous. Either buy new factory replacements or you have to take off the tape wrap of the harness and inspect them.

That is what I have been doing. Every harness (taillight, middle, dash, engine, headlight) has been removed, stripped of wrapping, visually inspected for char (found a lot!), non factory splices, connector damage. Then using my spare harnesses, repairing, replacing, re-splicing correctly, ohms check and rewrapping. Tedious work, let me tell you. I thought the dash was the hardest until I got to the headlight/battery harness. That one took the most abuse and had a lot of damage. The fusible links were really beat up. I am surprised the car did not catch fire previously after what I found.

I am still tracing, respliceing that harness. What I did find out was when the factory did joins of wires of ground, batt/alt wires, they wrapped the joint in an adhesive black duct type tape, then wrapped the harness in the non-adhesive kind. I am redoing mine the same way.

Good luck on your investigation!

Kevin


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
KevinW is offline  
post #6 of 15 (permalink) Old Aug 21st, 09, 07:44 AM
Senior Tech
Russ
 
Join Date: Jul 2009
Location: Gilroy,CA
Posts: 1,748
Re: Ground wire catches fire

I agree that the wiring in these 40+ year old cars can be scary. I found several places where insulation had been worn through from general wear or maybe backyard mechanics tugging and pulling on the wires.

Since I had planned to clean up and re-route much of the wiring anyways I replaced all the positive wires in my engine compartment with nice 10ga heavy insulated wire. I have also replaced all the ground straps with new straps and any ground wires with 10ga. It's easy to do, just go slow, solder all your connections, and cover with 2 layers of heat shrink tube.

Russ (RJ)
The Garlic Capital, Gilroy,CA

(sold June 15,2014) 1968 RS convertible that is not quite stock

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
rj68RS is offline  
post #7 of 15 (permalink) Old Aug 21st, 09, 08:10 AM
Gold Lifetime Member
Tom
 
Join Date: Mar 2008
Location: the 02176
Posts: 5,983
Re: Ground wire catches fire

I had a similiar situation after an engine swap in an old 4Runner. The (-) battery cable wasn't well connected to the block. In fact, I think it was connected to the inner fender. It was trying to return all the current through a weeny, ~ 12GA wire from frame to block. Weeny wire eventually smoked when trying to start the truck. Make sure your battery ground is well connected to your block.
That's what it was in my case anyway. Good luck.

'67 rs - ordered new by my Grandfather
327 L30, K-K, Deluxe int, tach & gauges, 12 bolt posi, 4 speed.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
-
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Melrose RS is offline  
post #8 of 15 (permalink) Old Aug 22nd, 09, 11:03 AM Thread Starter
Senior Tech
Lex
 
Lexlas's Avatar
 
Join Date: Jun 2009
Location: California
Posts: 1,279
Re: Ground wire catches fire

Well guys all you talk about sounds like you know allot about electrical issues. I really don't have a clue. I do know that my battery is in the trunk and a kill switch with it and another what seems to be a kill switch in the front under the steering colum but the button does not do anything when switched. I did switch it and thats when these problems started occuring. I took the car back to the shop where they just put in the new engine to see if maybe they plugged up something wrong but they replaced the wire that burned out and changed the starter because they said it keeps spinning when they connect it. Now they called and said that when they put the new starter and reconnected it all the headlight assembly wires all burned ! So they are tracking the electrical issue to find out where there is a problem. This all of a sudden electrical issue just got large. Don't know what will happen but i will take pictures and stuff when it's back in my garage, don't know when that might be.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


68 Camaro / 400 ci / 3.73 10 /
Edelbrock Performer Series 600 cfm no. 14054
Edelbrock Performer EPS Intake Manifold 27014

98 GMC Suburban / 454 V8 / K2500 4x4

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Lexlas is offline  
post #9 of 15 (permalink) Old Aug 22nd, 09, 11:18 AM
Moderator
Kevin
 
KevinW's Avatar
 
Join Date: Jul 2000
Location: Millstone, NJ
Posts: 11,048
Re: Ground wire catches fire

Sorry to hear that! Sounds like you will be better off buying new harnesses. The front kill switch hacks must have did something bad. It will be less money to buy new, then to have the old rebuilt using a shop $$$ IMO.

Kevin


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
KevinW is offline  
post #10 of 15 (permalink) Old Aug 22nd, 09, 12:27 PM
Banned
Ron
 
Badbird's Avatar
 
Join Date: Jul 2005
Location: Dearborn Heights, MI
Posts: 3,176
Re: Ground wire catches fire

I wouldn't even drive these old clunkers with the original wiring harnesses!....They are fire hazards for sure!.....That's why I completely rewired my car from front to rear with the Painless Wiring, 18 circuit wiring kit!....Now I can drive with no fear of being burnt up like a toasted marshmellow from the car catching fire!
Badbird is offline  
post #11 of 15 (permalink) Old Aug 22nd, 09, 11:49 PM
Senior Tech
 
Join Date: Mar 2002
Location: Austin, TX, USA
Posts: 5,277
Re: Ground wire catches fire

Burning ground straps is exactly what I think of when someone is posting about voltage problems and someone answers by saying "put more ground straps on it". The starter is a hungry beast and needs exceptional power and ground feeds that all the others are derrived from.

Dave
========================
68 Coupe, 350 w/ Edelbrock Performer RPM heads, cam, intake, 700R4, Dave's small body HEI
dnult is offline  
post #12 of 15 (permalink) Old Aug 23rd, 09, 06:38 AM
Moderator
Kevin
 
KevinW's Avatar
 
Join Date: Jul 2000
Location: Millstone, NJ
Posts: 11,048
Re: Ground wire catches fire

Quote:
Originally Posted by dnult View Post
Burning ground straps is exactly what I think of when someone is posting about voltage problems and someone answers by saying "put more ground straps on it". The starter is a hungry beast and needs exceptional power and ground feeds that all the others are derrived from.
Yikes! The ground straps are not used for the starter AT ALL! They are for the chassis grounds only. Starter gets its negative path through the engine block via the bolts. Make sure the threads and knurls of the starter bolts are unpainted and only the outside of the starter is painted. The negative battery cable has to go on the engine block! The positive wire is fed thru the relay.

Also make sure all your ground straps and ground wires are tight and touching bare metal.

Kevin


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
KevinW is offline  
post #13 of 15 (permalink) Old Aug 23rd, 09, 06:10 PM
Senior Tech
 
Join Date: Mar 2002
Location: Austin, TX, USA
Posts: 5,277
Re: Ground wire catches fire

Quote:
Originally Posted by KevinW View Post
Yikes! The ground straps are not used for the starter AT ALL! They are for the chassis grounds only. Starter gets its negative path through the engine block via the bolts. Make sure the threads and knurls of the starter bolts are unpainted and only the outside of the starter is painted. The negative battery cable has to go on the engine block! The positive wire is fed thru the relay.

Also make sure all your ground straps and ground wires are tight and touching bare metal.
Agreed. However a lot of rear-battery mounters are using the body and frame for ground and IMHO, that's asking for trouble. Despite all the heavy metal in the body / frame, there are lots of places for bad connections to develop and then those little ground straps become a serrogate.

Dave
========================
68 Coupe, 350 w/ Edelbrock Performer RPM heads, cam, intake, 700R4, Dave's small body HEI
dnult is offline  
post #14 of 15 (permalink) Old Aug 24th, 09, 07:42 AM Thread Starter
Senior Tech
Lex
 
Lexlas's Avatar
 
Join Date: Jun 2009
Location: California
Posts: 1,279
Re: Ground wire catches fire

Quote:
Originally Posted by dnult View Post
Agreed. However a lot of rear-battery mounters are using the body and frame for ground and IMHO, that's asking for trouble. Despite all the heavy metal in the body / frame, there are lots of places for bad connections to develop and then those little ground straps become a serrogate.
This might be why it became a problem. I wonder if also it had anything to do with the paint they did on the firewall. I'll be calling the shop later to see what is being done and where the short was. I wonder if i should replace the starter ?


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.


68 Camaro / 400 ci / 3.73 10 /
Edelbrock Performer Series 600 cfm no. 14054
Edelbrock Performer EPS Intake Manifold 27014

98 GMC Suburban / 454 V8 / K2500 4x4

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.

To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
Lexlas is offline  
post #15 of 15 (permalink) Old Aug 24th, 09, 04:46 PM
Senior Tech
 
Join Date: Mar 2002
Location: Austin, TX, USA
Posts: 5,277
Re: Ground wire catches fire

There wasn't a short perse. What happened was your main ground path developed a bad connection (near open) and your ground strap tried to carry starter current (which can vary from 100-900 amps). So the problem was the big ground not making a good connection and the little ground tried to carry the load.

I've seen lots of car stereo amps burn up from this same problem. Usually, big amplifiers are bonded directly to the battery. If the block ground develops a bad connection, the stereo amp tries to carry starter current. Inside the amp, the little copper foil traces will vaporize.

The block must always have a good ground connected directly to the battery. Even in rear battery mounted setups, I recommend running a heavy ground wire directly from the battery (-) to the block. But even then, if that big ground develops a fault, the same problems can develop.

Dave
========================
68 Coupe, 350 w/ Edelbrock Performer RPM heads, cam, intake, 700R4, Dave's small body HEI
dnult is offline  
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Team Camaro Tech forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address.
NOTE we receive a lot of registrations with bad email addresses. IF you do not receive your confirmation email you will not be able to post. contact support and we will try and help.
Be sure you enter a valid email address and check your spam folder as well.



Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome