MKIII 89' parasitic drain

[tobsta]

Hi guys,
Im writing this on behalf of my mate who owns an 89' MA70 and has recently been having troubles with his battery going flat after a couple of days or so. He original purchased the car with an old battery installed and began having issues with it draining. We assumed that the battery was gone and needed replacing. Especially after we had to recharge it multiple times. In the process of this happening I installed a viper alarm/ remote start system and his new stereo system which drains quite a large amount of power. I figured that he should really fit an optima or odyssey battery due to the new audio system but he couldn't afford one at the time and we fitted it with a rather decent lead acid battery for the mean time.
This is where things started to go downhill. The battery lasted a week and was running fine until one day he went to start his car and the battery was flat. I figured that he probably just had the stereo on for too long without actually driving the car and a quick battery recharge would be sufficient. The battery life has just gotten worse and worse since then and I know that the battery is probably now no good due to the fact that it has been deep cycled so many times.
I thought the there may be a parasitic draw in the car, possibly from the new alarm system that I fitted that could be the cause of the problem so i took my optima battery out of my car and tested the current draw when the car was completely off with the doors closed. It was ridiculously small... only about .9mA so i armed the alarm and tested it again. It jumped up to about 1.4mA but this still doesn't seem anywhere near enough to be draining a battery over a few days.
Is there anything else that could be the cause of the problem that I wouldn't be picking up with the multimeter? I think that if these measurements are current that he may have just deep cycled the battery too many times, and it has just gotten worse and worse since he's been recharging it.
If anybody could shed some light on my problem that would be greatly appreciated.

Cheers
Toby

 

[aloshan]

-battery might be screwed , take it to an auto parts store and get it tested
- alternator might be drawing current went off due to f*cked diodes , confirm this isnt happening
- lastly (what took me 5 months to figure out) check your relays and make sure none of them are stuck open

failing this , youve just got to keep pulling until the draw goes away...

 

[IBoughtASupra]

Get a volt meter and connect it between the negative pole of the battery and the negative wire terminal. Pull the fuses one at a time and check when the voltage goes down. Reinstall the fuse after you remove it before pulling another one.

I am not sure what the specs should be but maybe Jetjock can chime in here. Maybe 10 milliamps?

Here is a basic guide, but not Supra specific.

http://www.popularmechanics.com/cars/how-to/repair/how-to-stop-car-battery-drains

 

[Nick M]

Optima is going the wrong way. They are good at resisting heat and vibration (top battery killers), but suck at producing cranking amps. You could have replaced a weak battery with a low quality unit. Have you checked the charging system? Or does this happen over a few days when it sits? If so, you do have a draw somewhere. .9mA seems wrong. 50mA is the standard, and the PCM uses most of that for the keep alive memory (KAM).