924Board.org

[Cirno]

No, my car isn't a pile of rust. My battery cables are though.

To begin, when I got my car of course it had a dead battery. I put mine in but it was dead too. After I finally got it charged, I put in the key, tried to crank it...nothing. The lights dimmed, but no sound. So I tried a couple more times, then I heard a click and poof...all the lights went out, everythings dead. 0 power.

So I call it a night. Today after looking at some posts that describe the above situation, I'm convinced its my literal ball of rust that used to be a battery terminal.

It was easy to replace the ground wiring and terminal, however the positive leads are a whole different story. The cable leading down to the starter is green. I pulled the insulation off and it's green way way down the cable. The other three cables are in a slightly better state.

So now I'm at a crossroad; do I replace the entire cable leading to the starter? OR, do I splice in a short piece of cable from where I cut it to a new terminal?

If I do replace the starter cable, what is the connection like on the starter? Is it just a mash the wires on with a bolt style or some kind of plug? I haven't jacked my car up yet to look at it.

[Cirno]

Nevermind! I solved my own problem.

I just mashed the cables into a new terminal real good and used a lot of cleaner spray.

YAY, the starter works! The Car turns over! Now I'm waiting on my spark plug wires and water pulley.

[bnoon]

Green = copper's rust color = best to replace it if it's clear down the wire. Green tips near connection points can be cleaned up with warm water and baking soda. Remember to dry with compressed air and coat with eletrical grease before retermination.

Also, replace ALL of the grounds, not just from the battery to the body. You've got to get the ground from body to intake manifold, body to charge tube (if you're a 931), and intake to alternator. Also, make sure the + cable from the alt is good too.

Copper wires that are green with rust can have resistance values several times higher than a wire in good condition, and that means amperage must increase to feed the same load value... which leads to "poof" when amperage can get high enough to actually cook the wire or the item they are powering. Coat the connection points and any bare wire with electrical grease (most any grease is better than nothing) to help stall future problems.
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'80 924 Turbo - SOLD!
1986 Porsche 944 Turbo - SOLD!
Porscheless

[Cirno]

My Alt is missing its back shroud, and that terminal is also a ball of rust. I skimped a bit on grounding as I'm out of wire. I may just get a whole new (or used) alternator just to be safe.

If I remember correctly from my electronic courses, electricity follows along the outer edge of the wire, not through the center. So thats why corrosion on the outside of the wire would cause that resistance, right?

So many wires I'm gonna have to replace. Argh

[datatrain]

Current flow in the wire at DC is an electron flow through the wire.

At radar frequencies current flow is on the surface and is called the Skin Effect.
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'78 924 NA with Collector plate
33 year old car, with me for 21 yrs
Mint '92 318i BMW
Near mint '98 Buick LeSabre
VE7HFR