Looking for advice for my 05 r53. Recently the alternator went so I had it replaced. Brought it back home and all seemed fine except that it had this weird bogging problem where it seems to lose rpm when I hit the accelerator for about a second. I know they have lag but now it seems to bogg and I can hear the intake pulling in air while it does it. I assumed it was an intake leak and was going to figure that out on the weekend. Then I had to jump someone’s car during the week but instead of working like usual, my car decided to instantly die when we tried, and then I had to get both cars jumped. Since then I have driven my car decently far (~an hour) to charge the battery back up, then used it consistently for another couple days. After that I Let the car sit for a 2 days in my driveway and today I just tried to drive it again, but the battery is dead again. Sorry for the long story but I’m just not sure what the issue could be because if the new alternator was shot I wouldn’t have been able to drive it, and my mechanic told me that my battery is good.

didnt think this would be related but before this all happened I put on an m7 Cai and 16% reduction pulley.

Thanks in advance for the input

 

Seems like new alternator that you replaced is bad, or there is something draining your battery when the car is off. You will need a voltage meter to test the output from the alternator and also the current draw from the possible vampiric electrical device.

 

@gumbedamit thanks for the reply! So I checked the voltage from the alternator with my mechanic and it’s for sure working. He said my battery is probably just broken and that’s why it’s not holding charge. Do you know anything that could be draining the battery while it’s off?

 

Can you hear any noises? The power steering pump can fail and run continuously, it has a direct 100 A line (through a fuse only) to the battery, always on.