M50 - buzzing noise at the exhaust when warm

[BMWDriver]

Well, I've recently noticed when the engine is warm, at temp, that there is a strange sound coming from the exhaust. It sounds like a high pitched whirring, almost like an electrical motor. Nothing of the sort when the engine is cold. This is at idle, and I've had nobody with me to check it out when pressing the pedal.

Opening up the hood, I hear nothing irregular coming from there. I'll make a vid if necessary.

It's an M50 pre-vanos.

[genphreak]

It is the fuel pump in the tank. It may be about to die.

On the other hand, it may last for decades.

And/or go away when the tank is filled up. If the car is not running right, nad it isn't a myriad of other things, check your fuel pressure (or have someone do it) as fuel pumps can die intermittently or gradually causing flow limitations and your poor ECU's brain palpitations, as it works to resolve the resulting combustion problems.

[BMWDriver]

Well, the engine runs flawlessly. I'll open up the trunk to see, but I'm pretty sure the noise is coming out right at the exhaust. I wonder that the exhaust tip covers I put on a while back are causing a vibration that makes that noise.

[h2oyo]

Well, the engine runs flawlessly. I'll open up the trunk to see, but I'm pretty sure the noise is coming out right at the exhaust. I wonder that the exhaust tip covers I put on a while back are causing a vibration that makes that noise.

That could be it, you maybe able to tap on the tips and see if you get a vibration sound from them? I know I had an annoying rattle from my exhaust but it was bad cats.

[Rick L]

+1

Sounds like the fuel pump. Your car can run perfectly with noisy fuel pump until it fails and leave you stranded. Ask me how I know... And it sounded like it was coming from the exhaust too.