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Discussion Starter #1 (Edited)
I'm posting for others that may experience this in the future. This issue is resolved for me now, but I'm hoping future searchers will have a faster time diagnosing this issue as a result of this thread. This happened on my 11/02 build 325Ci with the M54B25 motor with 88k miles. No "mods" other than the NGK Iridiums I put in for shiggles.

Symptoms
  • Growling noise when turning to ON (but not start) in the morning. Sounds like the Chewbacca sounds commonly associated with the CCV, but louder and with a lower frequency. On some instances the vibration is felt through the floor.
  • Sound comes from the front, towards the floor.
  • Growling continues after start, and doesnt go away until the motor warms up to full operating temperature. You can still hear it sporadically after warm up albeit at a much lower volume.
  • Growls are most noticeable when letting off the gas after a spirited acceleration. This is when you feel it coming through the floor.
  • Power cut-off at WOT, with a sensation similar to hitting the brake when in fact you were flooring the gas pedal. This symptom manifested later on, and would have helped me skip the other parts I replaced if this showed itself earlier.
  • At 1/3 tank, the left fuel lobe had approximately the same amount of fuel as the right lobe, checked via the hidden cluster menu 6.0. This is a symptom that has been described by others when their fuel pumps were close to failure.

Replaced, in order
  • DME fan
  • CCV and related hoses
  • Fuel Filter
  • Fuel pump - this fixed it

This problem was tricky because all the growling sounds were coming from up front. It wasn't until the throttle lag at WOT and correspondence with other members did I finally replace the fuel pump. On a side note, BMA had the best price for the VDO pump.

Time between the first growl until the car started to choke at high rpm was about 4 weeks. Note that because I don't drive this car everyday, I had a chance to take my time. If you're having these growling sounds and you put more miles on your car than I do, time between noise to failure might be significantly shorter.

I corresponded with a few guys about this issue, but I'll let them share if they feel like it. As mentioned this issue is resolved for me now, but thought I would post it for the benefit of future searchers. E46s are getting older, so the likelihood of growling noises and failing fuel pumps become more likely every day.

Before all of this I thought the suggestion to replace the fuel pump at a fixed mileage or time interval was unnecessary, especially since this car is primarily driven on the freeway on the weekends. I'm starting to think there's good merit to that suggestion.

Edit 03/05/17 : Here's a video that illustrates the growling. Sounds a bit different when heard from inside or outside (this is outside obviously) but you'll get a good idea of what I'm talking about when switching the ignition to ON.

https://youtu.be/YDY6f7gRwgk
 

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cvx5832, I just wanted to thank you for posting your solution. My 2002 330ci just had a fuel pump failure at 235,000 miles with the exact symptoms you described. Your post helped me to fix the problem with certainty that the problem was the fuel pump.
 

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Discussion Starter #3 (Edited)
cvx5832, I just wanted to thank you for posting your solution. My 2002 330ci just had a fuel pump failure at 235,000 miles with the exact symptoms you described. Your post helped me to fix the problem with certainty that the problem was the fuel pump.
No problem. Thanks to Kalim too. He went through the same thing and gave me the certainty I needed that it was indeed the pump, even though the symptoms pointed elsewhere. Since I never saw the problem+solution documented in the same thread before, I posted it for whatever benefit to the next guy.

And 235k, wow. I barely got 90k out of mine...
 

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i only got it when i turn te key (not start). it makes some noise..

its not constant, but still...

time to replace mine also ;)
 

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This is why I have been suggesting that about 8 year is kind of the magic age for a fuel pump PM replacement. Most of the time with the non M cars, you can get to 8 years without being stranded, you can replace the pump and probably never have to worry about it until the cars 16th birthday.

I have not had many instances where the pump was specifically noisy like this, but I can in fact see how it could happen. Most cases there were some unusual performance issues that were thought to be due to a soft fuel pump.

I have had a pump for my 2006 E46 330cic Convertible on hand for over a year. Figured it was just a matter or time and it WILL eventually need to be replaced. Since I also know a lot of E46 owners, I figured I could always pull it from inventory in a pinch for someone else.

Now I just need to decide when I will install the pump in my car.

It is like the snow blower analogy. You live somewhere it snows a lot, you finally decide it is time to invest in a snow blower, you figure the next Winter season you will be able to put it to good use, the it sits for 3-4 years until you really need it!
 

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No problem. Thanks to Kalim too. He went through the same thing and gave me the certainty I needed that it was indeed the pump, even though the symptoms pointed elsewhere. Since I never saw the problem+solution documented in the same thread before, I posted it for whatever benefit to the next guy.

And 235k, wow. I barely got 90k out of mine...
No prob! Glad my experience could help someone else out. :thumbsup:

FWIW, my sedan was an M54 325i auto and started showing symptoms after 5 years and 40k miles. The noise was very loud and reverberated under the driver's floorpan, but only during priming and after I had let the car sit overnight. I had the transmission software updated under warranty for an unrelated delayed engagement problem and the noise would then continue after engine start into warmup, changing with application of the accelerator. I figure this was due to extra fuel demand from an increase in hydraulic pressure and hence load from the transmission. The fuel pump fixed it right away.
 

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I had a similar noise happen right under my feet on the driver's floor. The fuel filter wasn't rotated 100% correctly and was vibrating under certain circumstances while driving. Usually when on throttle/load. I put the car on the ol' lift and simply re-rotated the fuel filter the correct way. Noise went away
 

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Some more details about my fuel pump failure-

Before the hard failure of my fuel pump, about 3 weeks ago, my car started to misfire badly. I shutoff the engine, waited about ten minutes and restarted and it ran fine. I checked for codes and there where some misfires and that's it.

Ran fine for a couple of weeks. I noticed a little rough idle when first starting in the morning which I was attributing to the unusually cold weather. Then I started hearing a "foghorn" noise under my feet where the fuel filter resides. It's the growl that cvx5832 described. My fuel pump was also making more noise than I remember. Just recently, my "service engine soon light" came on. The codes were fuel trim banks 1 and 2, permissible range exceeded. But the car ran fine.

Then right before the hard failure it started misfiring badly again. I parked, went shopping and when I came back the car would not start. There was no noise coming from the fuel pump. It was dead.

The good news is that the replacement took about 45 minutes and now all is running well. I think better than ever.

The "foghorn" sound was very puzzling to me at first. I'm thinking it has to do with the fuel regulator not receiving enough pressure or enough constant pressure when the fuel pump is soft failing that causes the regulator diaphragm to vibrate loudly.
 

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Discussion Starter #9
The "foghorn" sound was very puzzling to me at first. I'm thinking it has to do with the fuel regulator not receiving enough pressure or enough constant pressure when the fuel pump is soft failing that causes the regulator diaphragm to vibrate loudly.
This is what I was thinking too, a resonance vibration of the FPR diaphragm.
 
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