e46 electrical problems...

[B2ThaZiZza]

Not sure if any of you guys can help me but on a e46 325i 4dr I replaced the fuel pump,fuel filter,spark plugs, and coils and the car will start and is able to drive but will slowly lose power and eventually kill the battery but if i manage to keep it running all of the dash lights will turn on and will be lit up but will turn off or dim when i pump the gas pedal.

Im thinking the alternator but i started the car and unplugged the battery and it still stays running. I also noticed a slight buzzing noise inside the car but im not sure where its coming from. The car will be ok to drive for maybe 20mins then if i leave it for a second to go into a store for maybe 20-45min it will not start and i need to jump start it to be able to drive it home then after that it wont start again.The battery is completely dead and wont charge.

[e30lov]

alternator. Lots of weird things happen when the car is low on voltage (dash lights lighting up as you described.) I would have the alternator checked at a parts store and go from there.

[Edev]

alternator. Lots of weird things happen when the car is low on voltage (dash lights lighting up as you described.) I would have the alternator checked at a parts store and go from there.

This. I've seen it many of times at work. Best of luck to you!

[B2ThaZiZza]

Ok will do. Thats wierd that after replacing all that the alternator would go out.

[JeST]

If it was the alternator your red battery light will be lit. If it were electrical I doubt it would let you start let alone drive even for a little bit. Sounds like the fuel pump is choking out and letting the car die eventually. I would double check your work.

[B2ThaZiZza]

I checked the connections on the fuel pump and the fuel lines and they are fine. i also checked the grounds on the ignition coils and they are plugged in and plugs are clean. Im stumped, its too dark to see so i will check tomorrow and i will get the alternator checked also.

[e30lov]

If it was the alternator your red battery light will be lit. If it were electrical I doubt it would let you start let alone drive even for a little bit. Sounds like the fuel pump is choking out and letting the car die eventually. I would double check your work.

if i manage to keep it running all of the dash lights will turn on and will be lit up but will turn off or dim when i pump the gas pedal

This statement leads me in the direction of inadequate charge from the alternator. The alternator simply is not providing enough output to charge the battery.

The alternator isn't 100% dead yet, but its on its way out very quickly.

[Liam]

What was the reason for the work you did?

Also: There is a sub harness ground at the rocker box cover that comes from the coil harness... Did that get left off?

And: One sure fire way to kill an alternator is to disconnect the battery while the car is running.

[JeST]

This statement leads me in the direction of inadequate charge from the alternator. The alternator simply is not providing enough output to charge the battery.

The alternator isn't 100% dead yet, but its on its way out very quickly.

Not sure if the OP noticed it or not but on an e46 if the alternator is done the red battery light will come on on the cluster. It will not come on for anything else (say a dead battery).

If the car starts then let it idle and check for the red battery light (should take less then a second to show).

Guess its just a coincidence OP is having issues after all of the recent work.

[B2ThaZiZza]

The car has more than 150k miles so i and my friend are doing maintenance since he will be getting this car from his sister for free. His sister never really took care of it. We still need to change the oil, do the belts, inspect and replace the brakes, check the radiator and hoses,etc. She also used to drive the car until it had low gas or would just shut off from no gas. Pretty much just drove the shit out of it never avoided potholes, curb checked the rims, lagged on maintenance until me or my friend would do it. This car looks nice theres no body damage and interior is pretty clean but i know this car got raped.

[mikeedler]

Not sure if the OP noticed it or not but on an e46 if the alternator is done the red battery light will come on on the cluster. It will not come on for anything else (say a dead battery).

If the car starts then let it idle and check for the red battery light (should take less then a second to show).

not always true.

I still do not for 1 second understand the thought of disconnecting the battery with the car running to see if the alt. is o.k.??????
put a multimeter on the battery with the motor off, see what the voltage isshould be about 12,0 volts, then start and see what it is, should go up to about 14,7 Volts--- yes, this is not 100% accurate, but it will help in a bind.

I also think alt. is bad.

[10Toes]

+1 for alternator and to test it with a multimeter at the battery.

[JeST]

not always true.

Care to elaborate? I worked on nothing but e46's for a living and would like to learn something new.

[brutus87]

e46s scare me
GL

[Pac1373]

Not an experience with an e46', but there is also a possibility (if I didn't miss reading something) that it is the battery itself.
I had the same issues with another type of car. after replacing the alternator, The problem ended up being a bad battery, it would not hold a charge at all, and all the systems were affected, no amount of jumping would help after awhile.

have fun, get battery AND Alternator tested before throwing your money at it.