E34: Can a dead battery cause engine problems?

[jim_b]

Hello there,

Today I found the battery of my '96 E34 completely dead (I suspect I'd forgotten the CD player on). Assuming the battery is just drained and still usable, I connected to the battery of a friend's car with the intention of starting and eventually charging my own battery. The engine was starting and then producing horrific (metal-to-metal) sounds and also vibrations, and then in 10 seconds it was going off (RPM were abruptly going from 1100 to zero). Then after the engine was off, a 5-second "rubber-against-glass" sound was appearing from under the hood.

Could the dead battery cause these problems (I suppose problems in the synchronization of the engine)? Has anyone experienced something similar or have a suggestion what I can try next before I take it to the service point?

Any help is greatly appreciated!

[Paul in NZ]

Your post is unclear wehter this is YOUR engine or the engine of the other car .I can imagine a car with a very low battery could run poorly at idle but once the engine is running fast enough to get the battery voltage up then it should run fine

[bloodyvsunday]

Metal on metal, and glass on ruber sounds!?


Ehhh doesnt sound anything close to a b attery issue..

instead of jumping the battery...
just disconect it and charge it at an auto store for free or yourself.
then try again.
battery might be shot.

[632 Regal]

your sound is most likely the belt slipping on the alternator pulley. Since the battery is real low the alternator is trying to pump full amperage which is definitely enough to cause issues. Start it up and drive it around for a few minutes and I'll bet you the noise goes away.

My car does this every time it sits for a few days ;)

[jim_b]

The problem was frozen battery liquid caused by the combination of a full battery discharge and temperatures as low as -15 C. In that situation, jumping the malfunctioning battery had allowed only to start the engine but not to sustain 12 volts, hence the engine was out of synchronization.

Replacing the battery with a new one fixed the problem. Thanks for your suggestions.

[bloodyvsunday]

glad its fixed.

Ie noticed that unless you have a brand new battery in these bmws, you should keep the battery in mind for every issue lol

[repenttokyo]

keep in mind that asking your alternator to charge a completely dead battery can easily kill the alternator.

[whiskychaser]

keep in mind that asking your alternator to charge a completely dead battery can easily kill the alternator.
x1
http://www.thirskauto.net/Alternator.html