I have an 89 supra turbo 5speed . My battery some how keeps going dead. I have no aftermarket add ons that could be draining my battery except for a sony headunit and blitz turbo timer. Also no after market alarm system. I had both the battery and alternator tested at Pep Boys and they said both are fine. The voltmeter on my turbo timer also confirmed the alternator output looks to be ok. I think my problem has to be somewhere in the connection between my alternator and the battery. There are two wire comng off the alternator... one with a plug end and the other wire is held on by a nut. One of these goes to the battery and the other im not sure where it goes(ground possibly). One thing I am going to try is sanding the wire loop that is held on by the nut to the alternator. Possibly getting a bad connection? Another possibility is my battery is bad a Pep Boys is wrong. Any thoughts would be great.
battery keeps going dead
- Thread starter SupraTrbo89
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Have you messed with any wires from the alternator since it was running right? There should be a connector from the harness that plugs into the back of the alternator and a thick black wire that sits on the probe on top of the alternator and runs to underneath the fuse box. i dont think anythign should be going directly from the alternator to the battery.
Take a test light, hook it to battery positive, and keep the test light to body ground. Pull 1 fuse out at a time and see if the light goes out. If it goes out, it's in that circuit.
You can also do a amp test, take your meter, measure in amps, take neg cable off and measure the neg cable and the neg battery post. This will only tell you how much draw you have.
You can also do a amp test, take your meter, measure in amps, take neg cable off and measure the neg cable and the neg battery post. This will only tell you how much draw you have.
SupraTrbo89;1969753 said:
Try unplugging your TT overnight and see if it helps.
How long does it take before the battery is 'dead'?
The one wire is the voltage regulator. Make sure the battery terminals are cleaned from all corrosion as a bad connection can cause charging problems.
I decided to do a compression test the other day to check the condition of my rings and when I did this the only thing i touched electrical related was the EFI fuse under the hood and the negative battery terminal. The car started a ran for a few days after this and I parked it over the weekend and when I tried to start it I had dim dash light lights but not enough juice to crank it over.....now that I think about I did touch the positive terminal which my ratchet wrench while I was putting the negative terminal back on and got a spark. I wonder if I shorted something or blew a fuse? The car still runs fine though once a new charged battery is in...thanks for the feedback so far
SupraTrbo89;1969753 said:
1. The battery is bad.
2. The battery is not being charged while running. This is indicated on the dash by a picture of the battery. That is your discharge light.
3. Drain, do what 3.14 said.
4. A bunch of corrosion on the cables inside insulator.
SupraTrbo89;1969838 said:
Does it go dead with the new battery? Either way, this is your clue.
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Nick M;1969857 said:
I never got a new battery.....I just recharged the one I had with a trickle charger. Tonight I reinstalled the alternator and put the battery back in. While doing this I sanded down the terminals and all connections going to the battery/alternator.
I do not get any dash lights indicating the battery isn't being charged. I need to buy a multimeter so I can test the draw on the battery. I do not drive my supra everyday as it is not my daily driver. How long should it be able to sit and still start up with the battery connected? If I know it's going to be sitting for a while I usually disconnect the positive battery cable.
SupraTrbo89;1969865 said:
My car sat while being repaired at a body shop for over 6 months. When they finished, I hopped in and started the car without a problem. I asked if they had started the car or charged it, wondering if the battery would last myself. They said they didn't charge nor start the car while being repaired as they had my IC off for most of it.
Well, cables will cause the car not to start, but shouldn't make the battery go dead, unless the cables cause a short.
My car doesn't last too long for a charge without some help, but that's the security system. I can measure draw with the system armed (Which is actually less than the system disarmed) and given current draw and battery capacity, I can figure out how long I've got reasonably accurately. I'm generally okay for about 4 weeks, more than that, and I need to use a battery maintainer, which I have on all winter.
Knowing what your standing draw is (How much current is coming from the battery with the car turned off as it would be) is important. Some things run all the time, like the dashboard clock, ECU memory and the like. Aftermarket and even the factory stereos have some "off" draw as well for things like radio station and other presets, a clock, and so forth. Security systems will also draw a little to monitor for the keyfob, keep memory and sensor status (Though often the most current draw is to light up the flashing LED.) Aftermarket amplifiers often have some leakage current while off, as might stiffening capacitors, sound processors, or other sound equipment.
A bad alternator will also cause current draw. A good one might allow a tiny amount of current while the car isn't running, but a bad one will allow a lot. Checking draw while disconnecting the alternator (Both the charge cable and the voltage regulator connection) can tell you if the alternator is a problem, which it may be, even if it is charging the battery while running.
I have a multimeter with an ammeter that's good for up to 10A, more than enough to measure how much current the car uses while it's off. I put it between the negative post and negative terminal of the battery, then pull the terminal off of the post. Watch the display for a bit, and average the draw with the security LED on and the security LED off. (Doors locked and closed, hatch closed, hood pin taped down, security system armed.) It should be measured in milliamps.
Also, if you can, see if the battery goes dead while the negative terminal is disconnected. That will only happen with a battery that has an internal problem, or over the course of a very long time.
My car doesn't last too long for a charge without some help, but that's the security system. I can measure draw with the system armed (Which is actually less than the system disarmed) and given current draw and battery capacity, I can figure out how long I've got reasonably accurately. I'm generally okay for about 4 weeks, more than that, and I need to use a battery maintainer, which I have on all winter.
Knowing what your standing draw is (How much current is coming from the battery with the car turned off as it would be) is important. Some things run all the time, like the dashboard clock, ECU memory and the like. Aftermarket and even the factory stereos have some "off" draw as well for things like radio station and other presets, a clock, and so forth. Security systems will also draw a little to monitor for the keyfob, keep memory and sensor status (Though often the most current draw is to light up the flashing LED.) Aftermarket amplifiers often have some leakage current while off, as might stiffening capacitors, sound processors, or other sound equipment.
A bad alternator will also cause current draw. A good one might allow a tiny amount of current while the car isn't running, but a bad one will allow a lot. Checking draw while disconnecting the alternator (Both the charge cable and the voltage regulator connection) can tell you if the alternator is a problem, which it may be, even if it is charging the battery while running.
I have a multimeter with an ammeter that's good for up to 10A, more than enough to measure how much current the car uses while it's off. I put it between the negative post and negative terminal of the battery, then pull the terminal off of the post. Watch the display for a bit, and average the draw with the security LED on and the security LED off. (Doors locked and closed, hatch closed, hood pin taped down, security system armed.) It should be measured in milliamps.
Also, if you can, see if the battery goes dead while the negative terminal is disconnected. That will only happen with a battery that has an internal problem, or over the course of a very long time.
If the battery is not being charged it can go dead from repeated cranking.
Also if the battery is old and has been drained a few times likely it needs to be replaced.
Also if the battery is old and has been drained a few times likely it needs to be replaced.
I didn't even notice that comment. I bought a new rectifier assy. They are selling for about 125-130 from Toyota online.
I have not had a chance to test the draw on the battery as I have been working 16 hr days this week. I will definatly get to it this tonight or this weekend and report back what I find. I have had to bring this battery back to life several times so it could be shot. Like I stated before I had the battery tested and was told the core was fine but Im not sure I'm convinced.
What is an acceptable draw I should see while the car is off? Dan I noticed you said to tape down the hood pin. How does the hood pin draw from the battery?
Also what is a DVOM?
Appreciate the feedback. Good stuff guys.
If the current checks out ok Ill disconnect the negative and see if it goes dead. Something tells me I'll end up buying a new battery but just wanted to check other things first.
What is an acceptable draw I should see while the car is off? Dan I noticed you said to tape down the hood pin. How does the hood pin draw from the battery?
Also what is a DVOM?
Appreciate the feedback. Good stuff guys.
If the current checks out ok Ill disconnect the negative and see if it goes dead. Something tells me I'll end up buying a new battery but just wanted to check other things first.
So I did the battery draw test and it settled at 1 to .09amps after about 5 seconds and if I kept it there for another 5 to 10 seconds it stayed consistent at .02 to .01. Not sure why the reading changes when I wait 5 to 10 additional seconds. If my battery goes dead again I'm going to buy a new one.