Melted Ground Cable..

[marco_1978_spyder]

I was starting the red spyder up yesterday.... It hadn't been started in a week or two so it needed some cranking to get the fuel flowing.

I don't crank for more than 6-8 seconds at a time, if it's a cold start and needs extra tries.

Just before I got it to start, I noticed some smoke in the cold air. My small cable ground is melting its caseing. Batt voltage before cranking 12.63

Engine block ground completed a circuit to get a battery voltage reading so everything seems connected. Standard battery to engine block ground and strap from block to firewall . I couldnt get the continuity sound to work, so I didn't test the connection that way.

Time to clean up connections?

[macman]

Yes Marko just because you have contenuitty it does not mean that it can handel the amperage.clean the cables or replace and clean and check cable at back of engine to firewall and from body to battery.

[lleelduo]

Back in the day, when these cars were new, they had a body ground problem. The connection to the body would corrode and lose contact. Then the shift cable would act as the body ground. Bad connection, it would eventualy weld the shift cable inside the sleeve solid! OOPS, my age is showing.

[cjbiagi]

I run a heavy bradied cable from the engine block to the chassis for just extra insurance. Cheap and easy...

[marco_1978_spyder]

I run a heavy bradied cable from the engine block to the chassis for just extra insurance. Cheap and easy...

I have one too.. Gonna check connections and go from there.

[zeke]

Check battery voltage while cranking. Lower the voltage is, the higher the starter draw will be. I use #4 welding cable on my vehicles for the engine ground and starter supply wires.

[cjbiagi]

I had custom replacement battery cables made and I went with the largest diameter cable that could still be used with the stock side post connectors, I think it is either #2 or #4, can't remember off hand. It's always better to run the heaviest cable and some of the stock ones are not very heavy at all.

[spencerforhire]

The smaller 10 or 12 ga. ground wire from the battery to the body is there to provide ground for everything BUT the starter. If it melted during an extended period of cranking, there is corrosion or a loose connection where the main heavier gauge wire attaches to the engine block.
A braided ground strap from the block to body would not really help in this situation; the ground path would still have to go through that small wire if there's a problem with the main large cable.

[zeke]

I use something similar to this for cleaning grounding points and lugs. The particles are extremely harmful to engines so be mindful of that. Clean the block and lug and put er back together and your problem should be solved. If not, replace the large cable and small one if you haven't already.

[dindin]

you sure its the ground wire and not the hot wire?? If it melted to the housing it may have rubbed against it and shorted to ground?? I never seen a ground melt before,
Al

[zeke]

If the large engine ground wire has resistance due to a bad connection, the starter will try to draw a couple hundred amps through the small ten gauge ground, thru the body and then thru the firewall strap. Ten gauge is good for 38 amps max in free air so it gets hot and melts the insulation. Seen it happen lots. If your battery voltage drops to eight volts when cranking, the starter current draw can double. Always charge a battery that has sat for a while before attempting to crank with it.

[cjbiagi]

This is where I had my custom cables made up http://www.wiringharness.com/
They made them with the stock side mount ends and heavy gauge wire. I also had them include the small extra ground wire that attaches to the fender. Very nice cables, should last a very long time and I don't have to worry about voltage drop. They don't list anything specific for our cars (surprise, surprise) but if you give them the specs they can make it.

[cjbiagi]

While working on the Monza to get it ready for the show I did take a close look at the battery cables, they were made with # 2 cable. That is quite a difference from the factory or replacement cables that are 6 or 4 gauge.