High pitch sound fuel pump.

[teagueAMX]

Originally Posted by MPHCPA

I have an 09 Z4 3.5 and the car went into limp home mode. It was the HPFP. The dealer told me this is an issue with the twin turbo.

Marty

You wonder why a company of BMW's capability and resources can't fix this problem!

Marty, how many miles on the car at the time?

[bemmers]

What's wrong with BMW??? They have had fuel pump problems for way to long to ignore this. People have complained when the 2003, 2004 Z's came out, as well as the 3 series. It's a SAFETY ISSUE!!!!!

[mikeinaustin]

the HPFP issue is well known and much discussed. they have had years to fix, but have not. yes bmw extended the warranty for 07-08 vehicles with the HPFP, but they have not done so for 09/10 vehicles. this is the main reason i went with the 3.0 engine instead of the twin-turbo 3.5 on my z4. i did not want to worry about getting stranded, randomly and potentially often (some people have had 5 pumps installed in 2 years).

[zEdP]

Hi again,

After the high pitch sound, the sound has changed. Now it has started humming with a low pitch sound (~600 hz) at a level that you can hear it with all windows closed (low speed driving). It hums not continually but is comes and goes with an interval of one second.

I guess it's dying; it is a matter of time. I hope the next few days it will survive.

I called BMW service, next Monday they will look at it.

EdP

[laphil]

Hope this works out for you. I'm really curious to find out what the dealer tells you it is.

[willysp]

I'm late to this thread, but no noises at all from my 35i (DCT) after 6 weeks and 1700 miles. I keep it in the garage with top down usually, so would likely notice as I drive in.

It would have gone back to dealer had I noticed any such noises.

[Dante]

Keep us updated! I'm very interested in what they say.

Originally Posted by zEdP

Hi again,

After the high pitch sound, the sound has changed. Now it has started humming with a low pitch sound (~600 hz) at a level that you can hear it with all windows closed (low speed driving). It hums not continually but is comes and goes with an interval of one second.

I guess it's dying; it is a matter of time. I hope the next few days it will survive.

I called BMW service, next Monday they will look at it.

EdP

[Alext]

You are lucky ...you have one of the rare, legendary musical fuel pumps!

[clwwong]

Where is the sound coming from? I hear some noises during acceleration, does the fuel pump sound happen during acceleration?

[Dante]

Originally Posted by clwwong

Where is the sound coming from? I hear some noises during acceleration, does the fuel pump sound happen during acceleration?

I've only noticed it on idle and it clearly comes from the back (drivers side). The Z4 has many whirring sounds for. e.g. brake energy regeneration and other features. BMW also designs such turbine like sounds.

But the fuel pump whine is clearly noticeable and doesn't change with RPMs.

[clwwong]

Thanks. I notice the sound is from the back, the whirring is like turbine. It changes it's tone with acceleration.....then I assume is normal now.

[zEdP]

Hi,

I didn't visit BMW service today because the 'humming' sound was not noticeable anymore. So I guessed that a fuel level of less than 3/4 could be responsible of muting the sound. So I filled it up and yes, the sound is back.

Tomorrow I will visit the service station.

@ Alext:
> you have one of the rare, legendary musical fuel pumps!

It sounds like a low female voice, singing ooo ooo ooo oooo oo ooo. Boring!

EdP

[Dante]

Thanks for the update!

[teagueAMX]

Originally Posted by zEdP

Hi,

I didn't visit BMW service today because the 'humming' sound was not noticeable anymore. So I guessed that a fuel level of less than 3/4 could be responsible of muting the sound. So I filled it up and yes, the sound is back.

Tomorrow I will visit the service station.

@ Alext:
> you have one of the rare, legendary musical fuel pumps!

It sounds like a low female voice, singing ooo ooo ooo oooo oo ooo. Boring!

EdP

The fuel pump is in the bottom of the tank to insure an adequate pick up when fuel is low. Normally, anything above 1/4 tank and the pump is completely submerged, which is good for keeping the pump cool. So one would assume that the sound would be even more muted when the tank is completely full, but in your case the more fuel the louder it get's.

Curious what the dealer's explanation is as it's somewhat illogical IMO.

[Dante]

I'm by no means an expert, but pretty sure the Z4 has more than one fuel pump.

Originally Posted by teagueAMX

The fuel pump is in the bottom of the tank to insure an adequate pick up when fuel is low. Normally, anything above 1/4 tank and the pump is completely submerged, which is good for keeping the pump cool. So one would assume that the sound would be even more muted when the tank is completely full, but in your case the more fuel the louder it get's.

Curious what the dealer's explanation is as it's somewhat illogical IMO.

[teagueAMX]

Originally Posted by Dante

I'm by no means an expert, but pretty sure the Z4 has more than one fuel pump.

You're right, the twin turbo direct injection engines have a second one. One is in the tank (low pressure) and the other is on the engine (high pressure).

The low pressure in-tank pump sends fuel to the engine, where the pressure is boosted by the high pressure pump for the direct injection system.

[twin turbo]

Originally Posted by MPHCPA

I have an 09 Z4 3.5 and the car went into limp home mode. It was the HPFP. The dealer told me this is an issue with the twin turbo.

Marty

I think I am in the same boat. The guys on e90post are telling me that the long cranks are the early signs of a failing HPFP. No limps yet and no codes, but lots of long cranks. Time to remove the mods and take a trip to the dealer. Oh joy...

[teagueAMX]

Originally Posted by twin turbo

I think I am in the same boat. The guys on e90post are telling me that the long cranks are the early signs of a failing HPFP. No limps yet and no codes, but lots of long cranks. Time to remove the mods and take a trip to the dealer. Oh joy...

I've heard they have a revised pump design so I'm curious if the replacement is a long-term fix.

[bemmers]

I hope all of you take your Z's in for service. My 05 3.0i was in for a fuel pump problem many, many times. They changed it 3 times, other times they didn't hear the noise, so they wouldn't fix it. It doesn't make noise every time you turn the key, and this being my "toy" with only 13,000 miles, BMW has given me a very hard time, actually they don't want to be bothered by me anymore. So, we're in litigation now. My warranty ran out, and I still have the noise. But, I still like my Z, just hate the embarrassment.

Like I said before, BMW has known about this problem since 2003 Z's to present. I looked up the part # on my repair orders for the fuel pump and guess what?????? It's for a 2004 Z.

[bemmers]

Has anyone found out about the fuel pump noise? Is the fuel pump different in a 2005 than a 2009? Just curious.

[teagueAMX]

Steve Dinan mentioned that BMW has been working with their pump manufacturer to improve the pump design. They have a new designs out that are supposed to taking care of the problem, however, by what I've read hear on the forum people are still having issues.

Another thing he mentioned is that dealers have sometimes automatically replaced the infamous high pressure fuel pump (HPFP) mounted on the n54 engines, assuming it was the problem without proper diagnoses. But in fact in some cases it turned out to be the lower pressure fuel pump mounted in the tank. He indicated that the some of BMW's efforts have been to put more diagnostic info in the latest ECU flash software to indicate which pump is failing.

[bemmers]

My 05 has had both, the siphon pump and the fuel pump changed (several times). Not sure what I have as far as HPFP & N54. From what year to what year did they change the pumps?