Why does my car whine like a lil' b****h

Hey everyone,
When I start my 330ci up in the morning, I hear this whine coming from under the car. I originally thought it was coming from the engine bay somewhere, but no, it's sort of coming from the rear axle / anywhere under the car. It whines, then starts to rumble, then car dies along due to the RPM drop (have to start a few times before it constantly runs). I originally thought it was the serpentine belt slipping, or some bearing in the alternator or cooling pump. But this is definitely not coming from the engine bay. The whine is intermittent and only happens when cold. Again, it's not a constant whine. It's like my car is crying when its cold.

Could this be transmission related? Or is it really coming from under the hood and you think it's something else? Open to any suggestions (no SEL light on either)
Thanks!

Probably your fuel pump is toast and also the filter.

+1 but you sound unsure from whence the sound is coming...so try using a hose/stethoscope to isolate it.

Thanks for your help! The more i think about it, the more the fuel pump makes since. Is there anyway to confirm that it is the pump?

Have someone else turn the key to position and see if you hear the pump prime. Then have them start it.

Or while your car is running, simply go to the back seat and put your ear to the rear passenger seat bottom. Do you hear a whine?

The fuel pump lives under the back seat. You said the noise is the belts/pulleys, but they are nowhere near the back seat.

BEFORE you do ANYTHING, you have to decide where the noise is coming from. Try opening the hood before you start the car. This helps to isolate the source as being the front of the car or not. Given your first post, I cannot figure out how anybody would arrive at the fuel pump as the problem because any noise from the pump would not make you consider belts and pulleys as the source.

One process that happens on a cold start, and never happens at other times, and comes from the same area as the belts and pulleys, is the Secondary Air Pump.

The SAP is a pump that lives at the front of the engine on the right hand side (as viewed from the driver seat). It is used on a cold start to force additional air into the exhaust stream to help the CAT do its job before it comes up to temp so that it can do its job by itself. The SAP runs for about 2 minutes, then stops. The bearings in the pump are known to fail, and the pump becomes very noisey when this happpens. The pump is noisey anyway, but the bearings make it worse.

Well, I know it's the fuel pump. Why? In stuck along side of the road. It made 40 miles before it dies out. 2 miles from home. It's totally shot now. If I prime it, it's only enhogg for it to start.

Well here lies a complication. If you had 40 miles left on the OBC then your fuel level sensor is inaccurate, not the pump. The sensor is on the left side and costs $90. Go run a bottle of 20oz Chevron Techron

Fuel level sensor inaccurate? But I hear the pump "not working and whining".

The OBC says I still have 90 miles or so.

Originally Posted by Solidjake

Well here lies a complication. If you had 40 miles left on the OBC then your fuel level sensor is inaccurate, not the pump. The sensor is on the left side and costs $90. Go run a bottle of 20oz Chevron Techron

He made it 40 miles before it pooped out, not 40 miles left on the OBC. OP, your fuel pump is done for. Replace it and your fuel filter.

Do I need to replace the fuel filter if I just replaced it 8k miles ago?

Originally Posted by jdstrickland

The fuel pump lives under the back seat. You said the noise is the belts/pulleys, but they are nowhere near the back seat.

BEFORE you do ANYTHING, you have to decide where the noise is coming from. Try opening the hood before you start the car. This helps to isolate the source as being the front of the car or not. Given your first post, I cannot figure out how anybody would arrive at the fuel pump as the problem because any noise from the pump would not make you consider belts and pulleys as the source.

One process that happens on a cold start, and never happens at other times, and comes from the same area as the belts and pulleys, is the Secondary Air Pump.

The SAP is a pump that lives at the front of the engine on the right hand side (as viewed from the driver seat). It is used on a cold start to force additional air into the exhaust stream to help the CAT do its job before it comes up to temp so that it can do its job by itself. The SAP runs for about 2 minutes, then stops. The bearings in the pump are known to fail, and the pump becomes very noisey when this happpens. The pump is noisey anyway, but the bearings make it worse.

Come on, JD. We all know the idler bearings and fuel pump belt are under the back seat!

Originally Posted by citrusjohn

Do I need to replace the fuel filter if I just replaced it 8k miles ago?

Then no, didn't realize you replaced it so recently. Run a bottle of Techron through a full tank for good measure then.

Originally Posted by BMWCruisn

unless you have an SULEV... then the whole tanks gets replaced at a cost around $8k.

Which is covered by BMW NA unless you're past the 11 year 130,000 warranty (or whatever the exact numbers are).

Hey OP, sorry to drudge this up out of the depths, but was it your fuel pump and filter? My car has recently started to whine on cold mornings. Sometimes it sounds like it's from the engine compartment and other times it sounds like its in the cabin.

Just like the OP was told, you need to isolate where the sound is coming from first.

Thanks bud. I was more-or-less interested in what he found was his problem. I'm gonna go through troubleshooting to pinpoint my problem. Sometimes it's just handy to know what others have experienced just in case. In my opinion anyway.

Originally Posted by choxor

Just like the OP was told, you need to isolate where the sound is coming from first.