The battery dies every night. I've been running a little expirament, and pulling various fuses from the vehicle, charging it, and letting it sit. It's either completely dead every morning, or not enough juice to even get started. Already replaced the battery trying to track this down, and I've run out of fuses to pull. Any ideas?

There's another set of leads coming off the battery,

other than the two factory cables. They look like bubba-made cables, but half the original car looks bubba-made anyway. Black one on neg, white one on pos. Any suggestions? Maybe those bubba wires are going to some old aftermarket alarm I couldn't find, and its draining the power? I found some wires under the passenger carpet that literally went nowhere, and were just cut. Hmn...

Although a better solution,
Anyone want an 86 z51 115k auto with 8/10 paint, 8/10 interior, and needs minor work? I'll let it go for 5,000. Not a penny less.

 

this might sound dumb, but do you leave the hood up at night while running your tests, i know my battery has died just from the underhood lights :cheers:

 

Nope.. in fact, I disconnected the underhood lights a long time ago. (In case they were on even with the hood closed)

 

Try removing the MAF. Had the same type of problem on Jens old 87. Looked and looked, car ran fine no codes but the MAF was screwed up somehow and making the battery die every night. Worth a shot..

 

Also try disconnecting the alt, sometimes a bad alt could cause this. Try also disconnecting the pos bat cable and put a volt meter inbetween the post and cable and see if your pulling a lot of volts. good luck let us know. :cheers:

 

Disconnect either battery cable and connect a test light in series with the cable.( between the cable & the battery) The test light will light if you have a draw. Make sure everything is off, check glove compartment and console cover. If everything checks out okay and the light is still on, un-plug the alternator. If the light was on in the first place, anything you do to make it go off is the cause. If the light didn't go on in the above test, then I would blame the battery. They do fail in this manner occasionally.Hope this helps

 

Cool.. thanks

 

There are 8 fusible links on the battery jumper cable next to the battery. One of these circuits could be drawing current and you can find it by unbolting these fusible links and disconnecting one at a time with an ammeter in series with the positive battery cable and watching for a drop in battery current.

 

stingray1970 and JFB are dead on with their advice. Follow it!

 

I also agree with this line of troubleshooting, but aren't certain things such as the ECM hot all the time? Might you see current draw on some of these circuits which would be normal ?

 

The ECM is on all the time and gets its power through one of the fusible links on the jumper post next to the battery. If the ECM is draining the battery, you will find this out when you disconnect the ECM fusible link. My 87 vette draws 28 milliamps when parked and this will not discharge a car battery overnight.


[Modified by jfb, 10:22 PM 1/2/2003]

 

You already got some great advice, here is what I did. I got a disconnect switch for the battery, one with a screw ****, install it on the neg bat post. I removed my battery and set it on the floor then hooked it to the cars bat cables with jumper cables. You can hook a amp meter across the disconnect switch. Disconnect all the cables from the jump start block the little junction block behind the battery and disconnect the one connector from the battery cable, so now the only thing connected to your battery are the cables and the starter. See what the amp meter is reading, should be pretty much zero, if not you have a problem with either your battery cables(could be bad connections at starter, gound point or bad cables) or your starter. The battery cables can corrode inside the plastic casing and be hard to see. If you are ok with everything disconnected install one of the jump start block wire at a time and check the amps each time. One note when some of the wire are installed your lights will blink drawing a lot of current and will peg your meter, this is where the screw **** comes in use the **** to connect the battery and wait for the lights to stop blinking then connect the meter and unscrew the ****.
Hope this helps you should at least be able to find which circuit is the problem, after that it could be a real pia to find the problem in the circuit, you can leave it disconnected over night as a test and see if your battery stays charged.
Good luck.

 

The ECM is on all the time and gets its power through one of the fusible links on the jumper post next to the battery. If the ECM is draining the battery, you will find this out when you disconnect the ECM fusible link. My 87 vette draws 28 milliamps when parked and this will not discharge a car battery overnight.

:iagree:

I just wanted to alert him that some circuits will draw current and that finding one may not be the cause of his problem.

I've spent too much time chasing my tail troubleshooting things that are operating normally.


[Modified by 1MoorTym, 9:51 AM 1/3/2003]

 

This good advice, start with the fuse block and make your way back. The only problem I had with the fusible links was trying to determine which was went to what (even with the diagram) You should also make sure you have a good battery and check your stereo equipement running off a seperate line off battery (ie amp)

 

I agree with those who think it may be the alternator. Since an alternator is an AC device, you have to translate it's output to DC for the car's electical system. This translation is done via a converter called a rectifier that contains 4 diodes which perform the conversion. If a certain one of them goes bad, it can allow reverse current through itself to ground, thus draining the battery as it sits. This can be measured, as pointed out, by hooking an ammeter in line with the positive terminal and see if there is constant current draw at rest.

 

If alternator diodes are shorted then it will discharge the battery but alternator cans till charge.Been there done that.

 

Do you have an aftermarket sound system? Maybe a short in an amp? :confused:

 

I'd check the easiest and simplest first. One of my door switches were intermittant and keeping the interior lights on all night but only sometimes. Since the interior lights stay on for a bit anyway, I didn't notice it right off being in a lit garage. The lights come on when I open the garage and having no night life outside the garage (ha), I didn't notice this for a long time. A little WD-40 on the switches cured this prob. FWIW.

BIG JIM

 

There are many good posts on this subject. I had a battery with top posts as well as side terminals. Only needed the side terminals. The top positive post even with a plastic cap on was touching the frame and as such drawing amps from the battery causing it to die every other day. :skep:

 

I just bought an '86 vert with same problem. The previous owner pointed it out before I bought the car. He removed the radio fuse from the fuse block and the battery will hold a charge. I am planning to track down the problem in the radio circuit, but suspect it is just a bad Bose stereo. The radio sounds ok but drains the battery. You might try removing the radio fuse.


[Modified by Mikedril, 6:27 PM 1/5/2003]


[Modified by Mikedril, 6:27 PM 1/5/2003]