Okay, what the hell. My car is haunted.

[kronus]

Basically, the way it goes: I unlock the car, power locks work fine. Door opens, lights come on fine. I sit down, turn the key, dash lights blink and then ALL power goes out. No clock from relays, no starter motor whirr, no interior lights, no dim OBC display.

I get out of the car, open the trunk, trunk light is out. At this point, there are several ways I've brought it back from the dead:

1) have it sit for a month in Farbin's driveway, swapping random parts that we thought were malfunctioning. Eventually it just starts up and drives.

2) take off the battery cover tray, and brush a jumper cable clip on the positive terminal of the battery. The rest of the cable is not attached to anything at this point. Suddenly, there is a spark, trunk light comes on, and it starts up fine and drives.

3) lightly press my hand down on the plastic battery cover tray. Suddenly, the trunk light comes on, it starts up fine and drives.

4) whack the alternator with a wrench. Same story, starts up fine and drives.

The battery is fairly new and stays completely charged after these episodes. When the car is not dead, it's working 100%.

I am stumped. Help. '87 325.

[Court M3]

battery ground cable maybe? Just going off 2 and 3.

[Adrian_Visser]

gremlins, fun times are the battery cable conectors corroded? could be that same thing for the alternator if there is corrosion on some conection on it.

[Knockenwelle]

Check and make sure the cables are both tight on the battery posts. Maybe try a known-good battery? Yours could have internal issues.

[kronus]

This is a known-good battery. Previous one wasn't.

I cleaned out and tightened down the clamps. We'll see if it happens again. Could the ignition switch do this?

[accident]

battery came out of my wrecked ETA. brand new in october.

check your ground cable connection to the body.

i doubt the ignition switch could cause this.

[kronus]

Ground connection is sparkly.

[StereoInstaller1]

I would explain what is going on, but I hafta go poop.

[mooseheadm5]

Bad connection at one of several places:
Battery + or - cable at the battery
Terminal block to main power cable
big red cable at back of starter
engine ground
battery cable to chassis ground in trunk

Lastly, possible bad cable, but remove, clean and tighten all of the above. You probably solved it by tightening the battery cable.

[kronus]

Bad connection at one of several places:
Battery + or - cable at the battery
Terminal block to main power cable
big red cable at back of starter
engine ground
battery cable to chassis ground in trunk

Lastly, possible bad cable, but remove, clean and tighten all of the above. You probably solved it by tightening the battery cable.

Excellent, thanks. Going to go down that list and clean tomorrow morning. Do M20's have two or three ground points? I could only find two(oil pan strap and under the diagnostic connector), just making sure...

[mooseheadm5]

Only those two, IIRC. Just so you know what is going on is that when there is a loose connection, low currents can flow through them, but when you put the high draw from the starter through that connection, the amperage basically frys that connection and oxidizes it, rendering it useless. The reason it may come back later is probably from heat cycling- the connection will expand and contract and move enough to make an OK low power connection again, until you crank the starter. These same symptoms can be caused by bad batteries or cables, but you always want to rule out the connections first, since they are the cheapest, most simple, and the most common cause of the problem.

[kronus]

Thanks. Technical explanation is greatly appreciated.

Once this issue goes away I can finally tackle my parasitic draw :|

[accident]

Once this issue goes away I can finally tackle my parasitic draw :|

Did you get a woman? </badjoke>

[kronus]

Did you get a woman? </badjoke>

nope. Probably better that way.

[mooseheadm5]

Start parasitic draw chasing with your ammeter. Most likely causes on an E30 are glove box light, trunk light, SI board, and any aftermarket accessories (radio, alarm.) Key off draw should be around 45mA tops. 400-800mA draw is usually a light bulb. 100-200 is usually something electronic.