More info on LPFP 'hum', please

[jeffp1105]

I've developed what I believe is the LPFP hum/whine. Just to confirm how to isolate it:

I have a 2011 E89 35I:

• start engine
• turn off audio
• turn off all climate control

Hum starts about 5-10 seconds after engine start. Does not change with throttle position, for me does not change with tank volume. Hum is consistent in volume and tone and comes from behind me somewhere (not clear left or right but definitely rear of car)

Here are my questions:

• What are your experiences with warranty replacement BEFORE it fails?
• Does the hum mean it will fail imminently or can it hum for a while?
• How long have you lived with the hum?
• Any chance my Cobb (Stage 1 Sport or Aggressive) 'caused' the problem?
• Any other advise on dealing with this?

Thanks guys!
Jeff

[jparnes1]

If it's the HPFP, then it is a known problem with a service bulletin for which BMW extended the warranty to 6 years/100k miles. Just bring it in and they'll likely swap it out for you. Not sure about LPFP. In any case, if you just let it go, your car will eventually go into limp mode and you'll need to get towed to the dealer.

[jeffp1105]

JParnes1,

Thanks for the info. I think I had ruled out the HPFP as it does not apply to the 2011. I see you have a 2012. Do you have info indicating more than the 09-10 Z4 was included in the exchange/warranty extension?

Thanks!
Jeff

[nicknaz]

Hi Jeff,

I recently had all 6 injectors and HPFP replaced on my 2012 model year 35i

The symptoms were long crank at start up and a rough idle (tachometer bouncing around a bit, and then some vibrations coming through via the steering wheel).

No hassles with the warranty replacement, but there was a few days wait for parts.

Interestingly, I DID NOT have any humming prior to the HPFP replacement, and I DID have some intermittent humming immediately after the replacement, that has not re-occurred for several days

My $0.02 is that all N54 owners should watch out for the HPFP symptoms, since (supposedly) my car already came with a revised part and it failed, and others have experienced failure as well after the 09-10 model years (which I believe are the only ones where the 100k mile warranty applies). Also, the hum isn't necessarily an issue, and the rough idle and especially long crank are the things to look out for.

[Crazykoh]

Originally Posted by jeffp1105

I've developed what I believe is the LPFP hum/whine. Just to confirm how to isolate it:

I have a 2011 E89 35I:

• start engine
• turn off audio
• turn off all climate control

Hum starts about 5-10 seconds after engine start. Does not change with throttle position, for me does not change with tank volume. Hum is consistent in volume and tone and comes from behind me somewhere (not clear left or right but definitely rear of car)

Here are my questions:

• What are your experiences with warranty replacement BEFORE it fails?
• Does the hum mean it will fail imminently or can it hum for a while?
• How long have you lived with the hum?
• Any chance my Cobb (Stage 1 Sport or Aggressive) 'caused' the problem?
• Any other advise on dealing with this?

Thanks guys!
Jeff

I had a lpfp hum. It was a soft high pitch noise from behind me or the passenger as I remember. Not terrible, but enough to be annoying. I asked them about it at my dealer and they replaced it under warranty before an actual failure. The pump is over the tank or something and is a pita to get to, apparently, so it took a couple of days (also they heard the first replacement whine, so they replaced it a second time at the same visit). No problems since. I try not to let the tank get below 1/4 full. I don't know if that makes a difference.

[redhot]

Originally Posted by nicknaz

Hi Jeff,

I recently had all 6 injectors and HPFP replaced on my 2012 model year 35i

The symptoms were long crank at start up and a rough idle (tachometer bouncing around a bit, and then some vibrations coming through via the steering wheel).

No hassles with the warranty replacement, but there was a few days wait for parts.

Interestingly, I DID NOT have any humming prior to the HPFP replacement, and I DID have some intermittent humming immediately after the replacement, that has not re-occurred for several days

My $0.02 is that all N54 owners should watch out for the HPFP symptoms, since (supposedly) my car already came with a revised part and it failed, and others have experienced failure as well after the 09-10 model years (which I believe are the only ones where the 100k mile warranty applies). Also, the hum isn't necessarily an issue, and the rough idle and especially long crank are the things to look out for.

Did the dealer mention the reason for the injector failure?? If I can take care of mine with using an injector cleaners every 1k mile then I would like to do that, however if the solenoid were to fail (regardless of fuel type) then there is no recourse....

[jpwolfe31]

We had our humming lpfp replaced under warranty with no issues. It is actually in the fuel tank and sits on the bottom with the fuel filter. There is an access door built into the side of the tank. The fuel cools the pump and I heard you might prolong its life if you keep the tank 50% full.

[nicknaz]

Originally Posted by redhot

Did the dealer mention the reason for the injector failure?? If I can take care of mine with using an injector cleaners every 1k mile then I would like to do that, however if the solenoid were to fail (regardless of fuel type) then there is no recourse....

They didn't mention the reason for the injector failure.

I use "top tire" gas and I get the engine oil over 250F on a regular basis, so I am GUESSING it was not a carbon build up issue

[tranquility]

Originally Posted by jeffp1105

I think I had ruled out the HPFP as it does not apply to the 2011.

It does, unfortunately. I have the same MY and recently had my HPFP replaced out of warranty but luckily still covered by BMW. Alas, my fuel injectors were out-of-pocket.

Originally Posted by nicknaz

Interestingly, I DID NOT have any humming prior to the HPFP replacement, and I DID have some intermittent humming immediately after the replacement, that has not re-occurred for several days

Hmmm, I thought that I was the only one, it didn't make sense to me because they only changed my HPFP and injectors and presumably didn't touch my LPFP, so I didn't know what to make of it. I still hear a faint noise. No idea what solution there is...previously when I had it a long time ago when I first bought my car, I simply switched fuel brands and it disappeared, so I always assumed it was that. Now, I'm going to have to figure it out again, if possible.

[BMWZ4RIDER]

My 09 35i has had the HPFP replaced in 2010 at the 8500 miles mark under warranty and has the 100000 BMW warranty coverage on this part. I also have the BMW 7/70 Gold Extended protection plan, so I am covered, so says the plan brochure.
The last 2 drives this week I have noticed this described "low volume HUM" coming from behind me and could not figure out what this was and where it was coming from.
The car starts fine and runs great (So far).
It is extremely annoying and will be taking the car in if it persists.

[zEdP]

Originally Posted by jeffp1105

Here are my questions:

• What are your experiences with warranty replacement BEFORE it fails?
• Does the hum mean it will fail imminently or can it hum for a while?
• How long have you lived with the hum?
• Any chance my Cobb (Stage 1 Sport or Aggressive) 'caused' the problem?
• Any other advise on dealing with this?

Hello Jeff,

• What are your experiences with warranty replacement BEFORE it fails?

I have had the same issue and requested to replace the low pressure pump. It took some time to get the replacement approved by BMW. Because it was quite "loud", they approved it after all.

• Does the hum mean it will fail imminently or can it hum for a while?

I'm reading the E89 forum quite frequently from on 2008. Correct me when I'm wrong but I have never read a post regarding a failing low pressure pump. There are several threads about the hum sound.

• How long have you lived with the hum?

After replacing the pump, the new pump started humming after several months but only when less than ~20% fuel is left, but not as loud as the previous one.

• Any other advise on dealing with this?

Still under warranty with a hum sound that is quite noticeable during driving, I would request a placement.