battery in hatch = battery drain

[grey88smokin]

84 SVO has had a battery drain since I put the battery in the hatch; I used the Taylor 0 or 2 gauge kit. I have put the DMM across the positive and the negative side of the battery; I read to do it both ways.

I have a draw of 2.7 amps. None of the fuses changed anything. I have pulled everything off of the hot side of the starter solenoid except the battery cable. That left me with a drain of .88 to 1.02 of an amp. Attaching anything such as the MSD box or any of the other wires that attach and inter-grade into that mess of wires brings the drain back up to 2 amps.

So I have been fooling with those wires, disconnected the alternator and ruled it out and now the tach is no longer working. Does this sound related to the problem or just something totally different?

I started the car to find the tach was not working, but I have verified that the charging system is functional and is charging the battery.

The battery is grounded to sheet metal in the trunk, I used the grinder to make sure I had a clean surface for the ground. However I do have a high level of resistance from the positive side of the battery to the ground location.

Searching I found that people that have in the past relocated the battery had problems with battery not charging with out an added ground from the engine. I am however having no trouble charging the battery and my grounds all have zero resistance.

I really need some advice or direction with this. I am not sure what comes next.

[Keasbey]

Maybe the positive side is grounding somewhere? Whats the resistance between + and the -?

[grey88smokin]

From the positive of the battery to the ground in the hatch there is no resistance. I will check tomorrow for the resistance between the + and - cables, that is what you meant right?

[THESVOTRUST]

Nest time you are running or KOEO -touch your brake lines under the hood going to the valve block!

IF warm (have seen them HOT use care)..........you maybe hunting for a ground the alum will let you know !

Mark
P.S. The dedicated grounds for chassie and eng to chassie will take care of it.

[grey88smokin]

Ok, I have the drain narrowed down to two things.

One is the horn/radio/clock fuse

Two is the thin brown wire, when connected the fuel pump primes.

I am in the process of digging through the interior trying to find the source of the drain on the horn/radio/clock fuse. It is not the radio itself, nor the horn, took them both out and nothing changed.

My autometer temp gauge keeps resetting itself now, I keep hearing the little motor in it resetting. This just started happening.

[Erics SVO]

The temp gauge resetting may be from the low voltage situation. I may "die" when the voltage hits a certain point. Then "wake up" when the voltage comes up enough after the drain stops. Maybe thats your drain? Where exactly is thr brown wire? Pic? Also I'm with Mark run back to the block and make a good ground.

[grey88smokin]

Came out blurry

http://good-times.webshots.com/photo/2851235250096549235kwMaoY

Those are the wires attached to the battery side of the starter solenoid, disconnecting the FP relay did nothing to change the drain that brown wire has on the battery.

The gauge is wired in with the oil pressure gauge, both are electric, they are both wired in together for power and power for the lights. Not sure if I knocked something loose on it or what. I have it disconnected and it was not a source of the battery drain.

I have ruled out the horn relay also, disconnecting it did not cure the drain. I dug through all the wires going to the clock, the radio, horn relay and came up empty.

Would a short finder help find the drain? Or would it have to be a short that keeps popping the fuse? I am really frustrated with the car, I feel like a dog chasing its tail.

[dagenham]

Put a simple test light between your -battery cable end and the post on the battery and see if it lights. If it does you have a dead short. I had this problem with the wife's Cougar. It drained a brand new battery over night. It turned out to be a bad taillight. Replaced the light bulb and solved the drain.
I dont know what happened to the bulb that it caused this problem, but I am 100% sure that it was the problem.

[Chuck]

I had a Mustang with a bad stop light switch. If the night was PITCH dark you could see the tail-lights barely glowing; otherwise you could not see anything wrong. Just sayin...

[BrianO]

did you have this problem before the battery was relocated to the rear? I'm curious how this stuff could just pop up all of a sudden when you had no issue prior to this. I would be checking what all I changed for the battery relocation and verify the battery is grounded very well. do you have subframes? I learned that grounding in the rear was not so good, until I got subframes connecting to the front/rear better. once I fixed the ground my charging issues went away. this was on my Gt..not the svo.

[THESVOTRUST]

Don't forget the importance of the secondary ground (small wire) on the driver fenderwell !!

Mark

[grey88smokin]

did you have this problem before the battery was relocated to the rear? I'm curious how this stuff could just pop up all of a sudden when you had no issue prior to this. I would be checking what all I changed for the battery relocation and verify the battery is grounded very well. do you have subframes? I learned that grounding in the rear was not so good, until I got subframes connecting to the front/rear better. once I fixed the ground my charging issues went away. this was on my Gt..not the svo.

I had to put the battery in the trunk. When I put the NPR in with the rotated upper the battery was in the way. I have been racking my brain, the battery was in the trunk with out issue for a month or so before it began to drain. So they probably are not directly related as I thought. No subframes yet.

I measured across the battery and got 2.08 amps, and have a drain of 2.08 amps. So there probably is a wire shorted, but the fuse is not blown. My head is spinning again thinking about it.

[Meotchh]

I measured across the battery and got 2.08 amps, and have a drain of 2.08 amps. So there probably is a wire shorted, but the fuse is not blown. My head is spinning again thinking about it.

Ok how did you hook up your ameter?

Someone else already mentioned the simple way to test this with a test light.
Have you done that yet?

[blueboss]

I have put the DMM across the positive and the negative side of the battery; I read to do it both ways. I have a draw of 2.7 amps.

From the positive of the battery to the ground in the hatch there is no resistance. I will check tomorrow for the resistance between the + and - cables, that is what you meant right?

You're contradicting yourself and unfortunately, your both wrong. In your initial explanation, you measured current draw across the battery which is wrong, but anyway.....then in your second statement, you measured RESISTANCE from the positive battery to to the new ground point in the hatch. Which, is also wrong. In the first example, all you've done is measure how much current is flowing THROUGH THE AMMETER ONLY. I.E. you've measured the battery. Does you no good. In the second example, you've measured the sum of the internal resistance of the battery with the negative cable. Again, does you no good.

I measured across the battery and got 2.08 amps, and have a drain of 2.08 amps. So there probably is a wire shorted, but the fuse is not blown. My head is spinning again thinking about it.

As Mitch stated and as I noted above, you do not measure current across the terminals of a battery. Dagenham was spot on with the test light example. Ironically, this also works with an ammeter. The correct procedure for measuring current flow in YOUR situation would be to disconnect the negative battery cable, connect one lead of your ammeter to the negative cable and the other lead of your meter to the negative battery post. You are now measuring the TOTAL circuit current. From here, you can start pulling fuses/isolating circuits from the main until you find the culprit.

Additionally, when verifying your grounds, they should be referenced to the negative battery post. Meaning: If you want to check the RESISTANCE of the engine side ground point that is the engine to firewall ground strap, you would place one end of your meter on the test point and the other on the negative post of the battery. My benchmark is anything less than .5 ohms is good. Above that, start cleaning the point until it's within spec. Once you've verified that specific point, you may now use it as a reference instead of the battery as you know it's a good connection.

Another point to add. You mentioned you isolated the alternator and that it charges without issue. Here's the problem: Inside your alternator, you have something called a rectifier bridge. This bridge has 4 diodes in it (among other components beyond the scope of this discussion) that basically turn the AC output of the alternator (how it got is name) in to rectified (not true) DC so that the rest vehicle can use it. If one of those diodes are bad, it will still charge the battery without issue but with one added benefit.....it will most efficiently drain a battery. Like overnight efficient.

So, if it were me, in addition to what's been suggested, I'd disconnect the alternator at the harness plug so that it's isolated from the battery and the car and continue troubleshooting until everything else is ruled out. Or, take the alternator and regulator to your local parts house that tests those things free of charge and do the deed.

[thomp22]

If you end up replacing you Alt. do yourself a favor and replace the Voltage Reg as well, there both cheap enough, and they work together. Learned the hard way.