biglarry13

I go a nightmare, This 91' has a direct open somewhere ? The battery with all doors closed no key in ignition will arc like a welder when connecting the POS terminal . Here's the odd part, the car starts, runs has no codes but the fuses all still good not blown are so hot they will burn you. left parked a new battery will fully drain ( I mean ZERO volts ) in less than 20 minutes. It's just sitting collecting dust I fear a fire on this thing. I've toned out everything under the hood O.K there. So getting ready to rip out the cockpit ?

hcbph

Sounds a little like what I had at one time. Here's what I found and how I tracked it down.

I had the negative cable unhooked from the battery and the positive hooked up. I used a DVOM and measured amps from the engine block to the negative battery post, in my case it was 19 amps. I used the gauge/meter shown (got mine at HF but I've also seen it on Ebay) - pull the fuses out of the fuse block one at a time, plug it into the gauge and plug the pigtail of the gauge into where the fuse was in the block and take a reading. Fuses seemed ok, but when I got to the circuit breakers in the front of the panel (had to make some jumpers to do those) I found one that was causing the draw. Turned out to be the one that controlled the power seats and door locks.
When I started tracing that circuit I found the wife had put a lipstick tube in the well with the power seat adjuster and something laying over it on the console was pressing down on the lipstick tube which in turn was pressing down and holding the power seat adjuster. Removed that and the drain went away.

Another group you can check is the power lug under the battery (assuming yours is like mine. Take the wires with the fusible links all off, and add back one at a time and use the block to battery and see if your drain comes back. If so, that's the circuit to check out.

Not guaranteeing that's your issue but that's how I found mine. Same methodology should help you find yours.

Hope that helps, good luck. Let us know what you find.

billschroeder5842

Take heed at :29

If it were my car, I'd do the following:
1) disconnect the battery
2) Pop ALL fuses and relays out of your box
3) As mentioned byhcbph check one at a time till you find your big draw.
4) Trace and fix.

You got something potentially scary there if things are hot to the touch and draws that fast. It is a matter of time before something happens.

pcolt94

Remove all cables and plugs from the alternator. That’s one of the few items that can draw that much current and is connected to the battery.

Then connect the battery and see if the short and sparking has gone away.

Purple92

OK - You say that the current draw is happening and no fuses are blown. OK - that means one of three things - either the current draw is going through a fuse, and the current flow is less than the fuses rating, or the current flow is not going through a fuse, or there is a short int he wiring somewhere...

My suggestion - pull ALL the fuses - and then reattach the battery cable and see if the current flow is still present. If it is - then the current is not flowing through one of those circuits. You can put all the fuses back, and try disconnecting things like the alternator (as pcolt94 said - it's one of the more likely large current drains - if the rectifier diodes fail - it can draw a good bit of power), the starter etc. that are unfused.

If the current is NOT flowing after all the fuses are put back - put half a dozen fuses back at a time till you find which group causes the current to flow- then either use a tester as described above - or go one by one in the bank.

If none of the above works - you probably have a short in the wiring before the use box, or in one of the unfused circuits. Time to start hunting.


GOOD LUCK !!!

hcbph

Good points Purple92.

It would be really helpful if the requestor did the test I noted about taking the negative battery cable off and using a DVOM and read from something like the engine block to the negative battery connection and see how many amps is being pulled. Give an idea of possible circuits it could be.

pcolt94

This is a bad idea with the size the OP has indicated the " arc like a welder". The current sounds to be much more than 10 amps. The home DVM or whatever kind of meter you have normally has a 10 Amp max rating. If you put that meter in series with the battery terminal you are going to blow the meter or at least the fuse in it if you're lucky. I personally would not go there from what I have read in post 1.

hcbph

Mine showed up as 19 amps when trying to track it down and didn't blow up either meter I was using at the time. Get one of the freebee's from HF and if it goes bad, so be it. Still need some idea of how much is being drawn off to try and narrow it down. If you have a better suggestion - I'm all ears and I'm sure the requestor is too.

pcolt94

I have several HF meters and a good fluke meter plus more and all are 10 amps. I think the current draw is just too much for any meter and it will be damaged. Most people are not going to have monster meters for current.

I suggestion was to start with disconnecting the alternator and as you pointed out the rectifiers are a very possible cause of high current draw.

If the alternator is not the problem, then I would disconnect any sub-cables to the maxi fuses and other areas. You would think with that current drain something would be smoking in some part of the car however the alternator may not.

Another attack of the problem is disconnect the positive side of the battery and with everything connected in the car measure the resistance of the positive cable. Then start removing the alternator or any other item you want and watch for a large change is increased resistance.

bac22

A couple of amps will cause sparks when connecting the negative lead, but considering the battery drains to dead very quickly it would seem to be a serious short.

I would work backwards on this problem by removing all fuses and then using the Cen-Tech circuit testing which at 30A should handle the short that you seem to have.

https://www.harborfreight.com/30-amp...ter-67724.html

Hot Rod Roy

Here's my trick for chasing shorts: Connect a good headlight in series between the battery post and the battery cable. When you've got a high current drain, the headlight will shine. If you've got a normal low current drain, the headlight may glow just a little, or maybe not at all!

This same idea works good if you've got an intermittent short that is hard to find, and keeps blowing fuses!

Hot Rod Roy

The resistance of the positive cable will be ZERO ohms. What are you trying to say?

pcolt94

You don’t understand, you're not measuring the resistance of the "cable". With the high current there is a much lower low resistance then there should be in the system that the battery is seeing.

The negative lead of the meter goes to chassis. The positive lead of the battery is removed from the battery. Then you measure between the positive cable and ground. The resistance is going to be low. Then when you disconnect the alternator, other cables or maxi fuses, you are looking for a sharp increase in resistance on the meter. When you find this point of increased resistance, you have found the short or the circuit that it is in.

You light bulb test will work also as I have used that also in electronics for over 40 years.
There's always more than one way to find shorts.

Hot Rod Roy

Way too complicated. Please re-read post #1 to learn more about the OP. With my trick (post #11), you can jamb a screwdriver between the battery cable on the starter solenoid and ground, and the only thing you'll see is a bright light! No sparks, no smoke, no damaged meters, and my system is cheap!

pcolt, your post #4 is probably correct.