Electrical Draw?

[ACHTUNG]

I'm having a problem with the electrical system in my 89 325i. I thought my problem was due to a bad battery so I bought a new one and I still have the same problem which is:

The engine starts right up when the battery is fully charged. I then shut the engine off and when I try to restart, I get nothing. Totally dead. I'm assuming there is a draw somewhere in the system however I don't know how to test for it.

Any suggestions?

[Brew]

Are you saying that the battery is dead immediately after the engine has been running, or after the car has sat for awhile, such as overnight?

To check for a 'key-off' draw, pop the trunk and disconnect the light. Make sure all the doors are closed, no lights are on, and the key is off.

Disconnect the negative terminal of the battery and connect your multimeter in series between the negative terminal and the battery ground cable. Make sure your multimeter is set to measure amps. You're looking for a amperage of less than 50mA. If you are higher than that, then you should start looking for the component causing the draw. Often a draw is caused by an aftermarket alarm or stereo.


If the battery is dead immediately after you shut the engine off, then you have a charging issue. Check your charging voltage with the car running-- you should have close to 14v. If not, first check your voltage regulator brushes (should be longer than 5mm IIRC). If they are good replace the alternator.

[ACHTUNG]

Are you saying that the battery is dead immediately after the engine has been running, or after the car has sat for awhile, such as overnight?

To check for a 'key-off' draw, pop the trunk and disconnect the light. Make sure all the doors are closed, no lights are on, and the key is off.

Disconnect the negative terminal of the battery and connect your multimeter in series between the negative terminal and the battery ground cable. Make sure your multimeter is set to measure amps. You're looking for a amperage of less than 50mA. If you are higher than that, then you should start looking for the component causing the draw. Often a draw is caused by an aftermarket alarm or stereo.


If the battery is dead immediately after you shut the engine off, then you have a charging issue. Check your charging voltage with the car running-- you should have close to 14v. If not, first check your voltage regulator brushes (should be longer than 5mm IIRC). If they are good replace the alternator.

It's dead immediately after I shut the engine off. I'll check the charging voltage. Thank you Brew.

[lordofthewaters]

Sounds like a grounding issue!
Check the engine ground that runs from the frame on the driver's side to the oil pan. Take your jumper cables and clamp one clamp on the oil drain plug, then clamp the other onto a bolt head or other clean well grounded place like on the steering rack. then try to crank it. If it works then you need to replace that ground, and I'd recommend going to the block with it instead of the oil pan. I had this problem a while back and it took me a month to figure out it was that gound even though it looked fine.

[ACHTUNG]

Sounds like a grounding issue!
Check the engine ground that runs from the frame on the driver's side to the oil pan. Take your jumper cables and clamp one clamp on the oil drain plug, then clamp the other onto a bolt head or other clean well grounded place like on the steering rack. then try to crank it. If it works then you need to replace that ground, and I'd recommend going to the block with it instead of the oil pan. I had this problem a while back and it took me a month to figure out it was that gound even though it looked fine.

I'll check that too. thanks.

[B2ThaZiZza]

get your alternator tested also just in case