need some help on this one. so twice now i have gone out to the car to start it and nothing!! no power, no nothing, so dead the lights wont come on. two weeks ago i drove the car all day no problems. parked it and it sat for about 4 days. came out that fourth day to go for a drive and dead! so i jumped it got it running and the elec choke was stuck on!?!?! (brand new holley). fixed that, but the car was charging. drove the car 175 miles that day with turning it off and starting, no issues all day. so i get home, park it, and two days later i decide i would wash the car. thing fires right up and seems to be fine, so im thinking SWEET!! not the case......so today i went out to drive the car to work and just to check i turn the light switch on.....nothing!!!!! something seems to be draining the battery enough in a few days to completely drain the battery. i know the alternator is working and the battery is a new interstate. basically everything mechanically on my car is new. oh yeah i should mention too, over the last few days i have been checking to see if its dead by turning the key and checking my volt gauge. and every day except today it has seemed fine. any ideas?!?!?!? thanks Jason
Look for a sticky/sticking brake light switch. May not be the problem, but I've seen it stymie the best. Charge your car back up, drive it around the block a time or two to warm everything up. Park it in its normal place, and then just before you go to bed, go see if the brake lights are on...if not...wait another day and see if it still starts. I don't know what type of switch you have, but anything that moves can get sticky - plungers that won't fully release, levers that won't either, even pressure switches have moving parts that can fail. Other option is to charge it up, and then put a VOM between the positive post of the battery and the REMOVED positive cable - see if there's a drain of any kind. Dome lights that stay on....either by forgetting you rotated the headlight switch or a sticky door plunger. Radio not slaved to the ignition switch that may be on, but turned low last week while you were talking to someone. Trunk or engine compartment light (not real common on hot rods) with sticky switch. Check that current draw (battery post/cable test) if the problem isn't obvious. dj
Find someone who can check the charging system in the car. Could be bad diodes in the alternator. Connect a test light between the negative battery post and cable, if it lights up and stays on, something is pulling current.
happened to me recently. it would start,run and then after being parked for a day,it would not start the next day. it got worse and worse. My battery cable(+)wa sold and was working sometimes. Inexpensive test. good luck
Check for current draw like mentioned above but use a multimeter and do it in-between the negative pole on the batt and the removed negative terminal. Almost sounds like if you haven't got a draw your battery is a dud!
Also make sure you battery terminals are tight and free of corrosion loose or dirty terminals can actually draw current
what type of alternator? Delco 1 wire or 3 wire, Autolite, prestolite, Motorola, it makes a difference in diagnostics for power draw on charging system.
well to reply to all of ya, my radio is not hooked up, my brake light switch is a gm style. and the brake light switch only works with the key on, so i know its not the brake lights. my alternator is a gm one wire that was rebulit by a good shop located near me. i dont have any dome lights, or door light switches. my setup is pretty basic and to me, i think it shoulndt be hard to find what the problem is with such a simple setup. also i have all new battery cables and a new rebel wire harness in the car. i appreciate the input guys and i hope i can figure it out. the trouble is im storing the car tonight for the winter so i might have to diagnose it next spring..... Jason
This is one of those intermittent gremlins that can drive you insane or insaner. It almost sounds like a bad battery, look for a possible loose post and never rule out a glove box or trunk light that gets left on. Also see what you have powered up that is hot all the time. But do go with the draw test and charging system check from someone who knows their stuff. Bob
Had one of these a while back, same problem. I've been fixing on cars over 40 years and have seen this once. Drive it daily or every other day and no problem, but after 3 or 4 or 5 days battery would be totally flat. Mine turned out to be the voltage regulator, or cut out inside the alternator. What was happening ? It seems that once battery voltage dropped to a certain point the regulator would connect the alternator to the battery. Since the alternator was not being spun by the engine at that time said connection only served as a drain on the battery. This is not supposed to be possible according the store that sold me the alternator, but a new alternator fixed the problem. I'm quick on this stuff, only took me about 6 months to figure out what the problem was.
so could i just disconnect the alternator and leave it for a while then check it and see what happens??
i got one doing the same thing right now.and im about to set it on fire!!ive always thought i was pretty good at fiquring out shit but this damn car has me feelin like a fool.i swear i can hear this car snickering at me.
I know the feeling. i got the car going in the middle of sep and has been problem free since...until now. but at the time i was driving it almost every other day so im sure it was enough to keep the battery up. i hate this kind of stuff. why cant it just all work out?!?!?!? haha
Turn the car off and pull the ground cable. If it sparks when you pull it you have a short (actually a long) that you need to chase down. If not you may have a dead cell in the battery. Take the batter to the local autoparts and have them check it to see if its shot or not.
You probably don't have a trunk light either but just thought I'd ask. I had a car doing what you describe, the trunk light wasn't going out when the trunk was shut. A clip on ammeter is handy for finding wires with current flow in them. You just put the ammeter against the wire (no direct connection needed) and it will indicate current flow.
If you've got no current running anything while the car is parked and it sits for a few days at a time, it pretty much has to be either a dead cell in the battery or the voltage regulator is draining the battery dead. My bet is on the regulator.
Well don't find out the way I did. I disconnected the battery and checked for a current between the ground lead and neg battery terminal, no problem. Then after checking some other stuff on the truck visually over several days and finding nothing I decided to check for current draw again. I found enough of a short to fry my old Simpson Multimeter. Should've used the battery cable and looked for sparks.
I got frustrated & installed a battery kill switch while trying to figure it out, a temp solution while I was trying to find the drain, after replacing the alternator the problem went away, BTW 48 Chubby; thanks for the explanation. Anyway, the kill switch still comes in handy.
Take your volt meter and check from the + terminal to the top of the battery case to make sure that you don't have a current draw across the top of the battery. I've seen batteries go dead in a matter of hours because of a draw across the top when they are dirty and damp.
Take a test light on with a light bulb in it. Connect it between the ground cable and ground. the bulb will glow the brightness will tell you how much current draw. Now disconnect the alt wire If the light goe's out thats your short. If the light still glows start removing fuses until the light goes out.The fuse that the light goes out is your problem.
Yes you are. Okay- who wired your car? Is it a harness kit, or is it 'factory'? Do you have a diagram? Without having a bigger picture, it would be hard to tell. However, the regulator is a likely cause. Have the alternator tested, I think your local NAPA will do it for free or cheap. Check for current draw first, as previously posted - between the - terminal on the battery and the cable.
Had one doing simmilar. Would hold charge for a few days before drained to low. Turned out to be a capacitor hooked to the voltage regulator(factory installed). It was bad and would slowly drain the battery. Since the replacement regulator was electronic cut the wire to the capacitor problem solved.
ok, i was confused about the regulator. i was thinking of the box that would be mounted on the firewall. i guess i didnt realize there is still one in the alternator. a friend of mine and i wired the car. i used a rebel wire kit. im going to use the test light method and track it down. shoudlnt take long to find it......i hope!
I had this problem once and it was the dome light staying on not enough to see but on, I say that only to let you know it can be a very small drain. I never run anything with a memory so I use a battery switch
The guys have covered all the areas that can kill a battery over time. The test light between the removed ground cable and the negative post on the battery is a good way to see if there is any draw with the key off. A dim light means slight draw and the brighter it gets the more draw there is. Even brand new alternators can have a bad diode on feedback current to drain the battery, and batteries themselves can have shorted out plates that bleed current off internally. We had a Buick that was fine 5 days a week when you were driving it for work, but the battery would die over the weekend when it sat unused. Turned out to be an internally shorted battery where a couple of plates were touching. During the week it didn't have a chance to go dead before you drove it and charged it back up, but sitting over the weekend would allow it to go dead. My Son just had the same thing happen to the Optima in his T bucket. It would go dead over a short period of time. Replaced the battery with a new Optima, no more problems. Don
The Jalopy Journal
