czentner

I posted a thread earlier this week. My car keeps killing batteries, I've gone through 2 in the last 3 years.

Alternator tested good, but I noticed I had a 90mA parasitic draw.

I pulled all of the fuses and relays one at a time but none changed the draw more than 1-2 mA.

Then I remembered how I pulled out the vestiges of an aftermarket alarm system probably installed in the 90s. There is also an immobilizer who has a single wire that connects to the pos terminal of the battery. I found out about the immobilizer one day after pulling the battery out and accidentally ripping this wire off its connector. When trying to start the car with this wire disconnected, the car would crank and fire for about 2 sec, then die.

So anyways, doing my parasitic draw test, when this wire is disconnected, the draw drops to 10 mA!

I tried chasing this wire but it goes down deep somewhere between the engine and firewall.

I think what I'm going to do is just wire it up to a hidden switch somewhere easily reachable from the driver's seat and flip it off every time I get out.

Anyone see any issues with this approach? What would you do? I'm scared to start trying to mess with wiring to an ancient aftermarket immobilizer...

odonnell

You would save yourself a headache by just removing the immobilizer....usually they intercept a coil wire and ground it.

Tom M'Guinn

I went through the same thing. The ancient Circuit City alarm was drawing current like crazy and I had no details on its wiring. I ended up removing the seats so I could lie on my back and trace the wires. In my case, they clipped the primary ignition power on the underside of the fuse box and intercepted it with the alarm. I didn't want to risk disturbing all the other wiring by pulling up the fuse box, so I worked on my back to solder the original wires together way up under the dash. Total pain, but 100% worth it to get that junk out of the car. If you dig in, I bet it won't be as hard to trace as you fear. Your switch idea is creative, but unworthy of a Porsche.

czentner

Hmm. I've ripped out most of the old alarm system and the car still runs. Good.

I've traced the wire that is drawing 90mA I think I have traced back to the Vitesse MAF.

I did not install the MAF in this car, do they need a permanent 12v power source? Or can it be a switched 12v source?

I guess it's time to email John....

odonnell

Should be getting switched +12v

There are many places to take it from in the engine bay.

fast951

Already replied to your email.

MAF needs a "Switched" 12V.

czentner

Thanks for the tips in your email, John.

I took apart the wiring at the MAF to AFM junction and sure enough, someone had extended the red wire for the MAF power using black wire and ran it direct to the battery pos terminal.

I found the cycling valve plug you mentioned hidden under the intake.

I fished it out and verified that it had power when ign on and no power with key out. Spliced the MAF power into that and now the car runs and my parasitic draw is gone! So exciting.

Thanks again!

Adonay

Good find hopefully you get to keep your battery charged now