Parasitic power drain - air compressor / pump
 

Hi, I'm a new member and this is my first post. This place seems like just the thing for me and my new car. Thanks in advance for any help.

I recently got a 1992 SSE from my dad and ever since I've had it, it has had battery problems. The battery currently in it is only about 5 months old as it was replaced just after I received the car. Since I work from home I only drive the car once every three days or so, and over time I've noticed the car starts getting weaker and weaker until a few days ago when it didn't start at all (now I keep it on a battery charger at night).

Over the few months I've owned it, occasionaly I'll hear a motor run for about 15 seconds in the engine compartment while the car is off. I never knew what it was, and statisticaly, it happened often for how little time I spent in/around the car when the engine wasn't running. Well just yesterday, I happened to be standing right next to the car with the hood up when the motor turned on, and I could see, hear, and feel that it was the air compressor that was running.

So, my question is... why does the air compressor / pump need to run while the engine is off (fancy suspension?), and what can I do to stop it from doing this and killing the battery (pull fuse or relay, fix leak)?

Also, just in case it matters...
1. The front? suspension chirps when I go over sharp bumps or potholes.
2. The power antenna failed a few years ago and my dad pulled the 15amp fuse for the 'power antenna / door locks' to prevent the antenna motor from running forever, that fuse had been missing until today. (today I pulled the relay so that I could replace the fuse - my interior lights work again!).

Thanks again.

I know Will (Willwren) has posted a fix for the compressor pump somewhere before. Unfortunately, unless you wanted to read through all his posts, I can't even suggest what to search for to find it. I'm sure he, or one of our other Gurus, will pipe in shortly. Rest assured, tho, ther is a fix!!

And welcome to the club! As long as you stay away from the lounge, there is a barrel of information to be found. Them people in the lounge are just wierd (And I am their leader!! :sillywilly: ) :lol:

Re: Parasitic power drain - air compressor / pump
 

ELC shouldn't drain your battery overnight, even if it runs twice as much as it should. It's just maintaining the ride height. I would suspect a slow leak, but again, nothing that would cause this by itself. Disconnect the clip on the compressor that holds the round black thing on. That's the dryer/check valve. Squirt some air tool oil in there. Put it back, and go back through the system, one connection at a time including the rear struts. Do the same. This can re-lubricate and seal the o-rings and may help.

There are two fuses that control ELC under the dash. #12 and #17. Pull these at night, and see if that helps in the long run. If they don't, I'll suspect that your alternator is under-charging your battery. The ELC relay is in the Maxifuse Relay center under your hood, but I don't recall offhand which one it is (it's not one fo the 3 closest to the driver).

Your suspension chirping is possibly a strut, but could be any number of things. We'll need more info on that. The antenna can be replaced quite easily with a unit from a wrecker. Should run you about 30-50 bucks, or you can simply put in a fixed mast antenna from an SE of almost any year. Any power antenna from 92-99 will work.

Re: Parasitic power drain - air compressor / pump
 

...which reminds me that I really need to dig out my writeup on how I fixed my power antenna when its core broke and let the motor run endlessly. It's pretty do-able, with a couple of bits from the hardware store...

I would suspect your ELC pump is running much, much more than it should. And I would also suspect a leak in the system somewhere. The ride is levelled out, then the air leaks until the back of the car falls down. Then the compressor has to turn on to pump it back up. This keeps happening because the air in the struts is leaking out.

Found solution
 

Ok, this is about a year late, but I figured I'd put this in for people with similar problems looking at search results.

My issue wasn't the air pump, (yeah, it runs a little too much, but no biggie). The problem was the alternator. For a while, the car had been at 12v when driving (as opposed to 14v) and then finally it started having serious electrical problems and power cut outs even while the engine was running. I replaced the alternator, and everything was good again.

This is a VERY old topic.