335 Owners: Is this noise normal?

[bikenski]

My car was in for service a few weeks ago for the long cranking issue, and the High-Pressure Fuel Pump was replaced. Now the car starts quickly every time, but the sound of the engine under acceleration is different.

When inside the car, with windows up and sunroof closed, I hear a sound while under boost and accelerating. The best way I can think of to describe it would be as if you were putting your index finger up to your mouth and making the sound to tell someone to be quiet - 'shhhhhh'. Prior to the fuel pump replacement I don't ever remember hearing any sort of turbo or intake noise whatsoever - the exhaust note overpowered whatever noise was being made.

I'm wondering if perhaps a vacuum line could have been knocked loose during the fuel pump replacement, or if I'm just being paranoid, and the noise is normal. There does seem to be a slight hesitation while under light throttle, between 2000 and 2500 RPM, but the car still leaps at higher RPMs, and/or with more throttle applied.

Just trying to get some more data points before I schedule another dealer appointment. Last thing I want is to get the car back with the "Could not Duplicate (ie. You're Crazy)" diagnosis.

[bikenski]

bump - 80 views and no responses??

C'mon 335 folks, help me out here. Do you hear your turbos inside of your cars?

[rooster3.0]

I think your software was updated. There are reports that the new software will create a low rpm lag and a slightly different engine/exhaust note.

[Wolf33]

i hear a slight swirl kinda noise...dont know how to describe it exactly but its not all the time...depends how i accelerate... that doesnt say much but maybe its something you cab work with...:confused:

[Pocket Rocket]

Allow me to clarify, before you start heading to the dealership.

My brother-in-law had a similar situation. His car felt WAY underpowered when one accelerated, so much that the car didn't want to move...and sounded differently than normal, a Loud swirl noise sound. It turned out that one of the turbos was faulty. The turbo was replaced, and all is fine now.

[Wolf33]

hmm interesting..well i guess i should be heading into the dealer then...

[MikeCee]

Yes, I heard from the techs that the new software is not good for the 335 :(

[blaze739]

i hear a swirl noise too but i always thought it was the intake or turbo.. so this isnt normal then? i do feel like my car is slightly underpowered.

[Wolf33]

i have nothing to compare the power too...i do hear the swirl was assuming the same... i wish more people would comment on the subject :)

[MIDRVR]

I took my 335i vert in a couple of weeks ago because of the same type of noise and the tech agreed it sounded like one/both of the turbos were either leaving the waste gate open too long or a software update was needed. I take it back in on the 19th for them to put it on the dyno and then fix it. I also have the "cold-tranny jerk" problem as well which they are supposed to fix/update. Car has 6800 mi on it - otherwise it has preformed well. I have noticed a very slight drop in gas milage with the apparent turbo problem and somewhat slower response but nothing else.

[jago]

can you avoid the SW upgrade and still R/R the fuel pump?
my cab sometimes does take too long to crank, but runs like a clock.
i desperately want to avoid the SW change.

[jmsent]

can you avoid the SW upgrade and still R/R the fuel pump?
my cab sometimes does take too long to crank, but runs like a clock.
i desperately want to avoid the SW change.

I had my pump replaced yesterday as part of the service campaign. My software was not "upgraded". My car now runs much better, even though I never had long cranks at startup. Less hesitation on acceleration and much smoother in general. No loss of power or increased lag. Obviously the original pump was marginal. I don't see anywhere in the bulletin where it states that software must be upgraded when the pump is replaced.

[Djpeak10]

1

[Djpeak10]

Go on you tube or something and find some videos of some turbo'd cars, and see if they make the same noise as yours.

My .02 in owning 2 turbo cars before is it is just your waste gate my man.

I didn't read the whole thread so if your question got anwered my bad.

[luisrz68]

is your car still under warranty?.................if it is, take it back, get a loaner and go for a ride on the weekend!!!!!!!!

[MIDRVR]

I took my 335i vert in a couple of weeks ago because of the same type of noise and the tech agreed it sounded like one/both of the turbos were either leaving the waste gate open too long or a software update was needed. I take it back in on the 19th for them to put it on the dyno and then fix it. I also have the "cold-tranny jerk" problem as well which they are supposed to fix/update. Car has 6800 mi on it - otherwise it has preformed well. I have noticed a very slight drop in gas milage with the apparent turbo problem and somewhat slower response but nothing else.

Problem diagnosed as the front turbo failed and must be replaced under warranty. Waiting for new unit to be delivered and installed. Will update when I get it back with impressions of drivability.