won't crank, neg battery cable ?'s

[87coupe50]

Hi all,

trying to troubleshoot a problem with my car. I'm currently deployed to Iraq and left the car with my wife to look after. She IM'd me yesterday saying that the car won't start. After some long distance patience and question I found out the car doesn't even crank.
Previously... she had some trouble starting it because the "battery was dying", so she used a neighbors charger, charged it and got it started. She since let it sit for a couple more weeks and went to start it the other day. Car wouldn't start again, so she put the charger on it again, but this time it didn't start. She sent me a pic because the small negative wire from the battery post "lools like it had been chewed on or something". It's not broken, but looks like it got heated up enough to melt the insulation about 5 inches from the battery terminal. I did some searching here on :SNSign: and came up with this.

That is correct. It is also the ground for the battery to chassis and is the ground for everything but the starter. On a car, a ground is the return path for electricity to get back to the battery.

The clamp on with 2 bolts battery terminal ends are a know problem causer. Corrosion gets in the clamped joint and works its way up the wire under the insulation. Avoid them like the plague...

I also have some wiring diagrams saved in my favorites but none of them show two wires (1 small, 1 larger) on the negative terminal. Just wondering where these wires connect and what they could affect to prevent the car from cranking. I need your expertise! What are your thoughts???

 

[87WhiteStang1]

ive had this happen... what i have concluded is that it was my starter and i am buying a new one now. the car used to crank decent when the battery was fully charged and now it only cranks every one in a while..i would turn the key and nothing at all when i had a full battery or was being jumpstarted. if i held the key in start position for a few seconds when it was not cranking it would start to burn the thin wire going from neg. terminal to fender wall. i have no idea why but i know the main thing causing it all is the starter.

 

[87coupe50]

Still working this issue: anyone know where the larger negative battery cable attaches to on the engine block? I know it's some where around the oil filter.

My wife was finally able to get the battery out and took it to get tested. It was low on charge but other than that... OK.

I had her turn the key to run and jump the two large posts on the solenoid (w/out telling her what to expect) boy, did I get an earfull when the sparks jumped at her. Anyways, after recomposing herself she tried it again and the car still wouldn't crank.

I'm thinking it's either the battery cables or possibly the clutch safety switch. Does jumping the solenoid bypass the switch? Any thoughts?

 

[HISSIN50]

I would not want my sig other trying to remove battery cable connections and cleaning them (they often suffer from galvanic corrosion issues). It just might lead to more issues than before..........

What I would consider is having her use a spare set of jumper cables to 'make' a new neg (and positive, if necessary) battery cable. The negative one can run from the neg battery post (be sure the clip touches the post in case you have a bad primary battery connection) and something like clean, shiny metal on the intake. This method also makes for quick diagnostics.

Kinda unrelated but something I could see needing to be done: If you decide to have her use a jumper battery (like using her car to jump yours), BE SURE she knows not to use the Mustang's negative battery post/terminal as a connection point for jumper cables connection.

Good luck.

 

[87coupe50]

thanks Hissin, you're absolutely right. I don't want her working on it (without me), but right now I don't have a choice. She pulled the connectors off the terminals with a pair of pliers, scarring them up. Just ordered a new set of cables. Now if I can get her to find out where the negative cable is connected on the engine block.
I am proud though, that she is out there wrenchin on a stang. in the cold... taking directions from me, 7000 miles away on a crappy phone connection. This should be the ultimate test of a marriage!

 

[jrichker]

The large negative cable bolts to the block down by the oil filter.
The small 10 gauge wire bolts to the body up near the winfdhield washer filler cap.

The picture shows the common ground point for the battery & alternator

Picture courtesy timewarped1972

The computer has its own dedicated power ground that
comes off the ground pigtail on the battery ground wire. Due to
it's proximity to the battery, it may become corroded by acid
fumes from the battery. It is a black cylinder about 2 1/2" long
by 1" diameter with a black/lt green wire. You'll find it up next to
the starter solenoid where the wire goes into the wiring harness