94 850 Turbo Parasitic Battery Drain - Very Strange Phenomenon

[scot850]

The sensor is built into the door lock mechanism for the courtesy lights.

I can't think of anything that should be causing the whirring sound you are talking about in the location of the A/C compressor or power steering pump. With the engine off and the whirring happening you could try a stethoscope or a long screw driver pressed to your ear to see if you can identify the area for the noise. I am thinking it is more likely the cabin fan is running due to a short in the resistor pack or possibly the engine fan. Some do run on when the engine is warm for a short time after stopping.

The issue with the lights going on and off is possibly a broken wire in any of the door cables where they exit the door and enter the 'A' pillar. It can also be caused by the rear doors. This is a slow process to buzz out the wires looking for opens or shorts in each wire. I have had to do this on several occasions.

Neil.

[rsmigel]

If you remove the -ve battery cable, and then connect a electrical tester across the negative terminal to the -ve battery connector, you will see the drain. If that is what you are doing, 10mA is a normal condition. On later P80's up to 50mA is ok.

Neil.

Yup, that’s how I measured it using a Fluke multimeter.

[PAT57250]

Bonjour
je vous ecrit de France
1) Mesurer avec un VOLTMETRE la tension au bornes de l BATTERIE
-A L ARRET environ 12,4 volts
-MOTEUR TOURNANT environ 13,8 / 14,2volts
si ok
2)DEBRANCHER LE petit fil SUR L ALTERNATEUR (EXCITATION)
Verifier si toujours debit en Ampêre
je pense que cela peut etre une DIODE du REGULATEUR DE TENSION de l ALTERNATEUR

by SO LONG AND GOOD LUCK

[RickHaleParker]

2)DEBRANCHER LE petit fil SUR L ALTERNATEUR (EXCITATION)
Verifier si toujours debit en Ampêre

Le régulateur de tension est intégré à l'alternateur. Il n'y a pas de fil d'excitation à déconnecter.

[fnord]

I found what created the whir. It's the device situated between the 1st and 2nd fuel injectors; it appears to have a vacuum line connected to the bottom. Not sure of its function.
If I leave fuse 15 plugged in, when I turn off the engine, these instrument panel lights stay on: low fuel, bulb out, battery, oil, brake, park brake, ABS, coolant, service. Could that be a problem with the ignition switch?

[abscate]

Yes or with wiring faults.

[budoboy]

Sorry it's been so long since my last update. I think I may have fixed the parasitic battery drain problem, or at least, made it into a much, much slower drain. While replacing other things in my car (PCV system, radiator), I discovered that the fuel system relay (up above the radiator) was acting strange. It started acting strange after putting everything back together. If I closed the hood while the engine was running, the engine would die. While cranking the engine, I could tap the relay and the engine would fire up. I replaced the relay, and besides fixing the starting issue(and occasional fuel cutoff on acceleration), the car can now sit for about 4 weeks before it sees the amount of drain I was seeing in only 2 or 3 days before. I am testing the battery every couple of days and it seems to drop abut .1 volts per week now. I don't know what "normal" would be as far as battery drain for a car sitting in storage, but this is a huge improvement in my mind. Thanks for everyone's advice.

[FireFox31]

Thanks for the long-term followup. I was chasing a battery drain which seemed to magically stop. Following your suggestion, I wonder if a device is malfunctioning only some of the time. I'll consider that.

[scot850]

'Normal' drain is about 0.010A - 0.050A (10-50 mA) depending on the car. The older cars I had (98 and older) were around 10-15mA. My 2000 'R' is about 45-50mA and part of that is the aftermarket Viper security system.

Neil.