HPFP: I have a theory

[john08135i]

I was wanting to take a poll on how many had there HP fuel pumps fail and whether or not they have mods.
Maybe all of those who are running piggybacks making more power are causing teh HPFP to run harder thus fail early. If so then will they keep failing?

When you take the poll it wont say who said yes to having mods so dont worry about that.

I am just trying to determine if there is a trend or not and are the NEW pumps built or designed better.

[Dr_Jones]

A better way at this might be...

how many miles till your original pump failed? (~4k for me)
how many miles on your replacement (#881) pump? (~7.5k)
Has your replacement (#881) pump failed? (NO)

[Judge]

Seems like most users on 1Addicts mod their cars so don't be surprised (or make any conclusions) if the majority of HPFP failures happen to people with modded cars. You're not going to get a good sample on this site.

I know there have been at least two members on this forum who've had the HPFP failure with a completely stock 135.

[martinsmu]

Seems to me that stock cars have more HPFP than Modded ones? Odd

[AtomiK]

Originally Posted by martinsmu

Seems to me that stock cars have more HPFP than stock ones? Odd

What?

[busyguy8]

mine is an '09, all stock, and failed at about 2k miles.

[BSM 135i]

mine went out 2 weeks after i bought the car, it was bone stock.

[ORIGIN M.]

They better fix this crap, if they want to sell cars.

Ridiculous!

[warpdude]

'09, all stock, got it replaced at around 4k miles. I'm at around 6k now and I may just be paranoid, but I've occasionally been getting longer cranks and/or really rough throttle application right after ignition :/

[jeremyc74]

Originally Posted by john08135i

I was wanting to take a poll on how many had there HP fuel pumps fail and whether or not they have mods.
Maybe all of those who are running piggybacks making more power are causing teh HPFP to run harder thus fail early. If so then will they keep failing?

When you take the poll it wont say who said yes to having mods so dont worry about that.

I am just trying to determine if there is a trend or not and are the NEW pumps built or designed better.

There have been tons of failures on stock vehicles, and by extending the warranty BMW is pretty much admitting that they have a problem and haven't been able to correct it. The HPFP is extremely complexe (as far as pumps go) and there's a lot of room for issues in the manufacturing of it, even if the design is perfect.

There's a good sticky with a lot of information on exactly how it works if anyone cares to take a look at it.

HPFP is under the engine management section:
http://www.1addicts.com/forums/showthread.php?t=204091

[ORIGIN M.]

They had better figure its killing sales accoss most of the model line.

Because you know it is!!!

[penny]

Just died. 10k miles, 12 months, mostly stock.

[Lester]

Should do a poll - How many fuel pumps that fail are driven on cars that the owner lets the fuel tank get to reserve on a regular basis, versus how many fuel pumps fail on cars where the owner runs the car only on the top half? This is one statistical correlation that would prove interesting. Does running on empty have a detrimental effect on our fuel pumps?

[Zuzu]

Mine failed before the mods at around 1500km's.

[jeremyc74]

Originally Posted by Lester

Should do a poll - How many fuel pumps that fail are driven on cars that the owner lets the fuel tank get to reserve on a regular basis, versus how many fuel pumps fail on cars where the owner runs the car only on the top half? This is one statistical correlation that would prove interesting. Does running on empty have a detrimental effect on our fuel pumps?

Why would the fuel tank level have anything to do with the HP fuel pump failing?

[BlackjackMulligan]

Originally Posted by jeremyc74

Why would the fuel tank level have anything to do with the HP fuel pump failing?

I had heard before that they are lubricated with the gas and they "heat up" when the tank gets low. I don't know if this is true or not.

But isn't the pump in the engine compartment? If so, how could the gas level of the tank affect it?

[jeremyc74]

Originally Posted by BlackjackMulligan

I had heard before that they are lubricated with the gas and they "heat up" when the tank gets low. I don't know if this is true or not.

?

That part's a myth. It was a problem on some early vehicles with in-tank pumps, but it's been solved for decades, but the people who had failures have effectively spread the word and it still persists. There's a plastic sump around the fuel pump that traps enough fuel to keep it cool even when the level is very low.

Originally Posted by BlackjackMulligan

But isn't the pump in the engine compartment? If so, how could the gas level of the tank affect it?

Exactly right. The HPFP that's failing is driven off the engine, and is mechanical, not electric. It's a 3 piston positive displacement pump with an electrically controlled bypass regulator. There's a pressure sensor on the inlet side that protects it if the feed pressure drops too low, and a pressure sensor on the outlet side (mounted on the fuel rail) that's used as feedback to the ECU for pressure corrections.

I've heard that the failures are some sort of seal inside and it's related to issues in the manufacturing process. (It seems like that's what an early BMW statement said, but I don't have a link to it so take it for what it's worth).

I posted a link earlier to the BMW technical documents that give an in-depth explaination of how the system works. If fuel level had anything to do with it, the 128i would have the same issues, because it uses the same in-tank pump as the 135i.

[TunedM2C]

Yeah, it doesn't matter if your stock or not.

[takrdown]

So for those of us that plan on keeping this car until well passed the warranty expires...is this a DIY capable job and how much is a new pump?

[penny]

HPFP is covered for 10 years or 120,000 miles. My SA told me this today when I brought it in cuz of a dead HPFP.

After 10 years...a DIY should pop up here.

[jeremyc74]

Originally Posted by takrdown

So for those of us that plan on keeping this car until well passed the warranty expires...is this a DIY capable job and how much is a new pump?

It seems like it's only taking a couple of hours for the dealerships to change it, so it should be DIY capable for a lot of people.

I think the cost is around $600, but I'm going from seeing it somewhere in a threads, so don't hold me to that. Maybe one of the guys who've had it changed can look at their service ticket and see if it's listed.

[penny]

I'll post that service ticket here tomorrow when I pick mine up.