Help: Low Pressure Fuel Pump (LPFP)

[1911A145]

Hey Guys,

I need to change out my low pressure fuel pump. I have been getting fuel cut on my car at WOT but it drives fine under normal conditions. I replaced the LPFS already and it did not solve the problem. I am looking at my logs and it shows that the PSI in the LPFP is dropping to 50PSI around redline. Josh at COBB believes that the LPFP is the problem and it needs to go. I've even went back to stock tune and the same thing happens. So maybe it is just on it's last leg... I don't know.

BMW Sells the entire LPFP assembly and it is plug&play. It is about $300 and change and I can swap it in myself.

Mw question is this:

Would it be best to just go this route and swapt it out, or should i take apart the current one and replace the actual LPFP with a Walbro unit and solder, heat shrink, re-install, etc?

Also, are there any DIY's on accessing this part or how to remove the rear seats on how to get to it on our 135i's?

Thanks!

[b1aze]

It looks pretty straight forward based on some of the DIYs ive seen. It depends on what you think you might want to do in the future. If you think youll go bigger turbo or higher E85 blends, do the Walbro now. If not, just replace the whole thing. It would be a lot cleaner and easier to just swap the whole assembly.

[1911A145]

Originally Posted by b1aze

It looks pretty straight forward based on some of the DIYs ive seen. It depends on what you think you might want to do in the future. If you think youll go bigger turbo or higher E85 blends, do the Walbro now. If not, just replace the whole thing. It would be a lot cleaner and easier to just swap the whole assembly.

Long term I plan on just getting a custom tune. I really just want to be able to race the car now but can only daily drive it under "grandma mode". I didnt know if it would be feasable or cheaper just to put a walbro in there and what the process entails, which part number walbro would be best, how to get to it, etc.

[135Pats]

I would replace the entire pump with the OE part, opening things up has caused some serious issues for the DIY’ers attempting an in-tank solution. Lines falling off, fueling issues, on and on. If you find the need for more E85 down the road, add a Walbro inline to the existing system to boost output. A more elegant (and cheaper) solution IMO.

[1911A145]

Ok... I guess I'll just swap in the OEM part and be done with it.

Anywhere I can find out how to remove the back seats to be able to ge to the damn thing? I cant seem to get the back seats out. HELP! lol

[135Pats]

Originally Posted by 1911A145

Ok... I guess I'll just swap in the OEM part and be done with it.

Anywhere I can find out how to remove the back seats to be able to ge to the damn thing? I cant seem to get the back seats out. HELP! lol

Not sure…but LMK when you do figure it out! I’ll be doing the inline Walbro when HFS-4 arrives. And have no idea how to get the back seats out hah.

[1911A145]

Originally Posted by 135Pats

Not sure…but LMK when you do figure it out! I’ll be doing the inline Walbro when HFS-4 arrives. And have no idea how to get the back seats out hah.

DAMNIT!

Hear me out... the OEM drop in unit is $320. I have a business acccount so my cost is $284 OTD.

The Walbro one is $85 bucks. But I would probably be sitting there for a couple hours with a heater, barbed connections, splicing, etc.

If I buy the drop in unit it'll be faster, and if I decide later on to want more fuel I can always do a back end flash and install the walbro as a booster. hmm... just trying to find the easiest/cheapest route.

[135Pats]

Originally Posted by 1911A145

DAMNIT!

Hear me out... the OEM drop in unit is $320. I have a business acccount so my cost is $284 OTD.

The Walbro one is $85 bucks. But I would probably be sitting there for a couple hours with a heater, barbed connections, splicing, etc.

If I buy the drop in unit it'll be faster, and if I decide later on to want more fuel I can always do a back end flash and install the walbro as a booster. hmm... just trying to find the easiest/cheapest route.

Easiest and cheapest? OEM bucket and LPFP + Walbro inline, no question. I’m sure you’ve read the threads of people having issues with the in-bucket solutions. The lines never hold, clamps are often insufficient; things get tangled or kinked, etc etc. Just sounds like an un-fun time for an unreliable solution. So OEM LPFP + Walbro inline + a fueling solution (BMS flash or Protune flash) you should be able to support a lot of E85 before HPFP PSI starts to tank.

[1911A145]

OK... OEM it is for now then. I find it interesting my LPFP is giving out... not something you read on here about a common problem.

Thanks.

[135Pats]

No, but watch it start cropping up. Alot of people are using E85 in these motors, it's only a matter of time. Oh well not a hugely expensive replacement at least.

[1911A145]

Originally Posted by 135Pats

No, but watch it start cropping up. Alot of people are using E85 in these motors, it's only a matter of time. Oh well not a hugely expensive replacement at least.

I only used 3 tank fulls of E30 blend! Thats crazy....

Trying to source a LPFP now. My dealer has none from the supplier! Says closest one is 3k miles away in Cali. would take a week to get to me

[icabod7]

Same thing seems to be happening to me (or at least that's what I suspect) -- anyone have the LPFP part number and/or a link to good DIY?

[1911A145]

Originally Posted by icabod7

Same thing seems to be happening to me (or at least that's what I suspect) -- anyone have the LPFP part number and/or a link to good DIY?

http://www.ecstuning.com/BMW-E82-135..._Pump/ES37461/

Just lift up on the bottom of the back seats and they will lift right out. on the passanger side there is a round metal cap. unscrew it, unscrew the seal, and just plug and play install the new pump. It's pretty straight forward.