85fortheDrive

I continue to seek causes for the return of voltage drops in our 84. I noted the other day, as I was pulled over testing voltage with a multimeter, that the charging post on the car seemed warm. Is this normal?

My issues always surface when there is added load on the system - lights, stereo. Might thewiring harness or a relay be involved?

Thanks and Peace,
Tim

docmirror

Take everything apart on the jump post and clean it carefully. Us a wire brush on everything, you can even dip in a mild acid solution. Reassemble and test.

jcorenman

No, that indicates a loose/dirty/corroded contact.

When electrical current flows through some resistance, the voltage drops and heat gets generated at the point of resistance. Every wire and terminal has some small resistance, but the voltage drop- and the heat- should be negligible. If the terminal is getting warm then there is excessive resistance.

The drill of course is to disassemble, clean and reassemble the connection. Also check the main battery-cable connections at the starter and the alternator. Be sure to do this with the ground strap disconnected, this is the main power-bus and is unfused.

dr bob

I'll go on record as being against adding anything that's corrosive to the procedure. Even vinegar (acetic acid).

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Use a fine wire brush or sandpaper on all the ring terminals at that post until they are all bright and shiny. If there's any corrosion apparent in the copper conductors at those ring terminals, consider replacing the terminals onto good copper, with a heatshrink sleeve added. I brush the whole assy with Vaseline --after-- it's completely assembled for longer-term protection.

The jump post is normally protected by a plastic cover that helps keep rain and carwash water out of the connections. It also helps protect the 14-pin connctor there for the FOE wiring harness that includes the wire from the alternator and battery. Get a new cover (<$10 last time I looked) if yours is missing.

123quattro

Wire brush for the win...

Mrmerlin

an ink eraser works equally as well and wont remove as much of the coating on the connection lugs

docmirror

It works wonders. Of course, someone always has to go all the way to pure HF, and leave the part in for hours, thus coming back to a melted stub.

a DIP in MILD acid, followed by a decent flush removes less base metal than some brushing meathods, which was my first choice. But, I guess it's not for the faint of heart.

sigh........

85fortheDrive

Doc, Jim, John, Bob and Merlin:

Okay, I will clean all contact points at the post, the alternator, and the starter. A couple of years ago, I scrubbed all ground points on the car and so I have a little experience with that process. I'll unhook the back ground strap before touching anything.

You guys are the greatest...

Peace,
Tim

928SS

there are lots of contact cleaners that won't create a disaster too. some require water, some don't .

could also be a battery issue. a bad cell can create all kinds of strange issues/shorting/poor electrical system performance, etc...

I'd test the batt, and then just clean / check all connections from the bat up to the front.

buy at least a six pack first, to be properly prepared for whatever you find.

Imo000

Sandpaper leaves ridges and reduces surface area. If you can, use steel whool.

Mrmerlin

also pay attention to the ground strap if your hatch area is wet after washing the car or it otherwise getting wet from rain or snow then it a good chance the ground strap is corroded

Alan

Well maybe its obvious but everything in my engine bay gets hot...

But maybe if the ambient is cold enough that isn't the case for you...

Anyway check the relative temperature between the jump post and other similar metals nearby - as long as its not hotter then them it means nothing.

I assume it is warmer than other nearby items from what you noted - but make sure before you worry too much (I assume you have cleaned these connectors before given the issues you have had...)

Alan

j.kenzie@sbcglobal.net

Hi Tim,
I agree with the idea of careful inspection and cleaning of the connections at the jump post. If it is hot, compared to other nearby surfaces, then there is a high resistance path present there. It could indeed be corrosion or there could be a partially broken wire that is conducting through only 1 or 2 strands. Once you get things cleaned and any bad wires fixed, you can reassemble the connections tightly and cover with dielectric grease to protect from water and oxidants. I also agree with using fine steel wool to clean the connections, if not a brass-bristle brush is also nice.
Good luck, and I'll talk to you soon.
Dave

Fogey1

There's a product called Deoxit that works well.
http://store.caig.com/

It's not cheap but it lasts. I've had a can around for a long time, based on good things i heard. I remembered it the other day when I opened a severely corroded battery compartment in a radio and tried for the first time. It's not instant, but I came back to shiny clean contacts.

M. Requin

If the "jump post" is warmer than normal, it is carrying current, which means simply that it is shorting to ground. Look at the associated wiring.