Battery Voltage Dropping

garagedude · Post by **garagedude** » Fri Jun 22, 2007 6:58 pm

I have an 84 BII with a voltage drop problem. I'm loosing about 1/4 of a volt per day from my battery. This was doing it a while back so I needed a bigger battery so I thought I would get an "Ultima" yellow top battery. This battery doesn't drop voltage unless hooked up. Where should I start looking for a voltage drainning problem? Any ideas would be great.

Post by **Nobody** » Fri Jun 22, 2007 7:42 pm

If you pull a battery termial and hookup a test light in between the battery post and terminal, the light will come on if there is a draw on the system. Then you can pull fuses and see if the light goes out. If it does not go out, then start unplugging plugs one at a time. That should get you started.

garagedude · Post by **garagedude** » Sat Jun 23, 2007 6:40 am

Are you talking about "plugs" as spark plugs? Would the test bulb not come on just by being in the circuit if its between the battery and terminal?

Post by **Nobody** » Sat Jun 23, 2007 7:03 am

Plugs is referring to the various electrical connectors in the engine compartment. Hook the light between the neg bat post and terminal, and not it will not come on unless there is a draw on the system. Keep in mind there could be some draw from clocks, computers and dome lights.

garagedude · Post by **garagedude** » Sat Jun 23, 2007 7:55 am

thanks for your help. I'll let you know what I find out if I do? Next will be trying to get the exhaust bolts out to replace the exhaust gaskets that are making all kind of noises

garagedude · Post by **garagedude** » Sun Jun 24, 2007 11:04 am

I hooked up a small 12v. bulb to the negative terminal and didn't see any sign of light, so I opened up the door, dome light came on, small bulb lit up a little. When I turned on the radio the small light didn't come on? or when I turned on a small dash light thats on a cig. plug. What to do next?

Post by **Nobody** » Sun Jun 24, 2007 1:10 pm

You should get a test light, it will be more sensitive, or even better, many multimeters and can read current up to 10 amps.

There are just too many possibilities to guess. It's a pain, but you just have to start narrowing down list of possibilities. But first you need the right tools.

Bob Myers · Post by **Bob Myers** » Sun Jun 24, 2007 7:16 pm

I would hook the battery back up and pull the hot wire to the alternater and look at a small draw from there. Using a small test light between the wire and its corresponding terminal should yield no light. Any dim flicker at all and the rectifier pack is going or gone.

garagedude · Post by **garagedude** » Mon Jun 25, 2007 7:43 pm

Thanks, Now whats a rectifier pack?

Paul · Post by **Paul** » Tue Jun 26, 2007 12:38 am

a rectifier basically transforms ac voltage to dc voltage ......... but i believe he is saying either your voltage regulator in this case ..... or the coil for you ignition ..... depending on the motor in it.... because the 2.9 uses a distributor, but the 2.3 used a distributorless ignition, and i am unsure about the 2.8 but i think it was a distributor ignition ..... the main difference there being the 2.3 would have a coil pack made up of several coils ...... in which case it could be considered a rectifier pack ..... and i know the 4.0 alsao runs a distributorless ignition system or coil pack .... somethings i would like to know to try to help is .......

1) does battery seem to charge when motor is running ....... if so it probably wont be the regulator, unless charging at a weak reading ....... although this is still a possibility
2) another thing that can cause your problem is a bad sensor ...... but most likely not the problem if it does it when the engine is off and the key is not in the run position......... normally this would require a bad ignition switch, becasue the ecc relay being off, the starter relay being off, normally would stop voltage from being applied to any sensors
3) and if your starter solenoid is going bad or sticking, it could cause it ......... though it would cause the starter to hang most likely though and not shut off, although it does contain a coil that grounds through its housing and allows the contact to close...... but again the starter relay would have to be energized and would require the ignition switch to be on normally
4) keep in mind that radios, CB's, radar detectors, and especially amplifiers for stereos will cause a power drain on any electrical system ....... regardless of ignition position.... this is including cigarette lighters ........ This would be a good place to start to look
5) TFI ...... although some might disagree ...... the TFI module if it is starting to go bad can indicate a power drain on an electrical system....... but this will usually only take effect when the ignition switch stays closed across one contact .... the solution there would require both the TFI and ignition switch to be replaced because there would be no voltage applied with out the ignition switch being on normally ......... not start position but run position
6) headlight switch, dash lights, dome lights, brake lights, trailer wiring harness, and emergency flashers, turn signals ....... are normally energized when the ignition key is off ......... (This would be a good place to start to look)
7) ecc relay, fuel pump relay, and starter relay are un energized when the ignition switch is off ............

(IF YOU NOTICE MOST OF THE ELECTRICAL SYSTEM IS UNENERGIZED WHEN THE IGNITION SWITCH IS OFF) you might start by replacing the ignition contact and see if it helps with the problem, i had to replace mine 3 weeks ago and it costed me $8.00 for a new switch and took about 20 minutes to change ..........

i am not refering to the key ....

i am refering to the contact block attached to the upper side of the steering wheel, it has 2 screws in it and about 15 wires that energizes the majority of the electrical system in the vehicle.

if the run position of the contact is stuck closed then it could effect any of the sensors in the vehicle, and mine was stuck closed but would still turn the motor off when i turned the switch to off, becasue it contained 2 contacts inside the block for the run position and was turning of my electric fuel pump, i replaced mine becasue it was draining my battery the same as you are speaking about yours doing.......

hope this helps you find the problem, and as i said any of the above or numerous other things could cause your problem but i would start with a check of the ignition switch first

garagedude · Post by **garagedude** » Tue Jun 26, 2007 7:03 pm

Hi, Here's some info to your questions as best I can do
Number 1. Battery charges good when I drive it some. If the truck sets for about 3 weeks the battery will be down, might start, might not. Battery is a new Yellow top Optima Deep Cycle/Starting battery. Truck did the same thing over the winter so I put the new battery in thinking it was the battery which was old. The battery voltage stays around 13.2 volts when UNHOOKED from the truck.
2. The ignition switch seems to work properly at this time
3. I've not had any problems with the starter sticking, not working or continuing to run.
4. The first think I cked was my CB radio, small dash lights, etc. All are unhooked at the present time.
5. TFI was replaced last year.
6. All are working properly.
7. I didn't think that the 84 with carb system had an electric fuel pump.
I do have a new relay on a Ramsey winch but its unhooked too.

Bob Myers · Post by **Bob Myers** » Tue Jun 26, 2007 7:06 pm

Pull the hot wire from the alt and put a test light in series with the alt.

Post by **Nobody** » Tue Jun 26, 2007 8:03 pm

Bob Myers wrote:Pull the hot wire from the alt and put a test light in series with the alt.

I agree. You have to get a test light and follow the suggestions. It's a very good possibility that it's the voltage regulator or alternator, but you have to test.

Paul · Post by **Paul** » Wed Jun 27, 2007 1:49 am

well with the return answers given, i would say that the most likely problem would be the voltage regulator as before mentioned by the other guys...... test lights are inexpensive at most auto part stores ........ and it is the appropriate tool for the job ....... i recommend that you follow their advice as it is probably the most likely cause ...... if you still dont find the problem, you might consider pulling the fuse to your radio if it has a digital display because the clock in it and the memory storage for channels, over a month of sitting will cause a discharge in the electrical system, although it should be quite small .........

garagedude · Post by **garagedude** » Wed Jun 27, 2007 6:06 pm

I purchased a test light. Alternator was ok. After some cking and some luck I found that a wire with an inline fuse going to my second fuse block under the dash was powering the tach and tach light constantly. After changing this to a switched postion so that the tach/light is only on when the key is on, the battery stopped draining and the test light doesn't show any draining anymore. Thanks everyone for you help. I'm thinking the duraspark conversion is next. Garagedude