Fuel pump assembly diy?

[ray7792]

Hey,

Does anyone have tip or guide on replacing the fuel pump on these cars?
Think mine is starting to go, loud humming/whining sound and slight shudders when idling.
Seems to be getting a little worse as time goes on regardless if fuel level.

I've been trying to find a guide but have not had any luck. Anyone here done it themselves?
Is it similar to the e85 z4 guide here https://www.pelicanparts.com/techart...eplacement.htm

Just have to remove catback and heatshield?

Thanks!

[NoQuarter]

Not too hard but not pleasant either working under a fuel tank.

Remove the exhaust, remove the heat shield, be sure you have the proper wrench to remove the pump.

fmorelli may have some tips. He did his recently.

[ray7792]

Originally Posted by NoQuarter

Not too hard but not pleasant either working under a fuel tank.

Remove the exhaust, remove the heat shield, be sure you have the proper wrench to remove the pump.

fmorelli may have some tips. He did his recently.

Thank you for mentioning the wrench, I'll need to double check on that...

[rjahl]

Originally Posted by ray7792

Hey,

Does anyone have tip or guide on replacing the fuel pump on these cars?
Think mine is starting to go, loud humming/whining sound and slight shudders when idling.
Seems to be getting a little worse as time goes on regardless if fuel level.

I've been trying to find a guide but have not had any luck. Anyone here done it themselves?
Is it similar to the e85 z4 guide here https://www.pelicanparts.com/techart...eplacement.htm

Just have to remove catback and heatshield?

Thanks!

These pumps make noise when running. There must be a way to check delivery pressure before assuming the pumps is dying.

INPA has some good tools to test these things.

[paris1]

[QUOTE=rjahl;23808159]These pumps make noise when running. There must be a way to check delivery pressure before assuming the pumps is dying./QUOTE]

Particularly when the OP owns a 2014 which should have the later design pump and injectors, if I'm not mistaken. Someone chime in here with more knowledge on the subject before this guy wastes a lot of time and money!

[ray7792]

[QUOTE=paris1;23808183]

Originally Posted by rjahl

These pumps make noise when running. There must be a way to check delivery pressure before assuming the pumps is dying./QUOTE]

Particularly when the OP owns a 2014 which should have the later design pump and injectors, if I'm not mistaken. Someone chime in here with more knowledge on the subject before this guy wastes a lot of time and money!

Hahaha thanks for the concern~
I won't be doing it just yet, but its just that the whine and slight shudders at idle have gotten significantly more noticeable just within these last 2 weeks.
No long cranks or anything yet so may wait for then.

I have a cobb AP, apparently it can check the lpfp pressure delivery, I'll probably log it tomorrow...supposedly 72.5 PSI is the OEM's target

Edit: Z4 doesnt have the necessary lpfp sensor for logging.

[fmorelli]

Unfortunately there is no direct way to know the LPFP pressure. In fact folks are running into problems with the EPK now trying to install the Walbro 525 Hellcat pump (versus the typical Walbro 450) upgrade. Some of this is sensor related, and unique it seems to how the Z4 system works differently than the other N54 brethren. We call that, #z4tax

Doing the LPFP is a PITA on the Z4, unlike any other BMW where it is behind the rear seat cushion and a 15 minute exercise. I'll pick up from NoQuarter comments. You also want to empty the fuel tank. Not it is dual hump. You can run it as low as you feel comfortable. Then you have two choices: either use a siphon or when you crack the LPFP seal allow the passenger-side tank hump (where the LPFP lives) to drain into a bucket. Make sure either way, you are not in a close space. The fumes are pretty heavy duty and not good for you. The siphon sounds like a nice idea but in my experience exceptionally difficult to figure out if the hose is in the near side hump (passenger side is the fuel cap) or the hose is on the driver side. Obviously draining the driver side is not helpful given the dual hump. Be prepared for gas to come out when you break the LPFP seal, regardless of siphon or not.

Note inside the tank are actually two pieces - an internal filter and the pump. (see RealOEM). In the diagram I highly recommend buying a new filter kit (#3). BMW calls it a lifetime filter, if I recall. Note it is a "kit" which in BMW-speak means it comes with the o-ring seal. If you are not going to replace the fuel filter, then purchase a new seal (#4). I recommend also buying the screw cap (#5). Two reasons: if you are in a rusty area, I've seen those rust. Second if you beat it up during removal, easier to just have a new one. During reassembly I recommend some oil on the o-ring so it seats well, and any kind of grease (bearing, white lube, etc) on the ring when it goes back on.

To remove the ring, you can buy a tool for it - there are many for as little as $15 (check eBay), or you can use a punch and hammer and tap it to break it loose. When you have the screw cap off, you will have to wiggle the filter to break the seal. Just be ready for fuel to come out the bottom side. Once drained, you can reach up inside and pull the pump out, which hangs inside the tank. This can be done by feel, pretty easily in my opinion. The filter and fuel pump bucket use quick disconnects for their interconnects - pretty easy as well.

Assembly is reverse and pretty obvious. When restarting the car, fuel pressure builds pretty fast. If I recall the CAS kicks the LPFP on when you open the driver door, so it is up to pressure when you hit start.

Hope some of this helps you. Remember to manage emptying the fuel - that's the worst of it.

Good luck!

Filippo

[Lurcher]

Originally Posted by fmorelli

Remember to manage emptying the fuel

Betting this is like emptying a radiator - it's never truly empty until it spills on you....

[ray7792]

Originally Posted by fmorelli

Unfortunately there is no direct way to know the LPFP pressure. In fact folks are running into problems with the EPK now trying to install the Walbro 525 Hellcat pump (versus the typical Walbro 450) upgrade. Some of this is sensor related, and unique it seems to how the Z4 system works differently than the other N54 brethren. We call that, #z4tax

Doing the LPFP is a PITA on the Z4, unlike any other BMW where it is behind the rear seat cushion and a 15 minute exercise. I'll pick up from NoQuarter comments. You also want to empty the fuel tank. Not it is dual hump. You can run it as low as you feel comfortable. Then you have two choices: either use a siphon or when you crack the LPFP seal allow the passenger-side tank hump (where the LPFP lives) to drain into a bucket. Make sure either way, you are not in a close space. The fumes are pretty heavy duty and not good for you. The siphon sounds like a nice idea but in my experience exceptionally difficult to figure out if the hose is in the near side hump (passenger side is the fuel cap) or the hose is on the driver side. Obviously draining the driver side is not helpful given the dual hump. Be prepared for gas to come out when you break the LPFP seal, regardless of siphon or not.

Note inside the tank are actually two pieces - an internal filter and the pump. (see RealOEM). In the diagram I highly recommend buying a new filter kit (#3). BMW calls it a lifetime filter, if I recall. Note it is a "kit" which in BMW-speak means it comes with the o-ring seal. If you are not going to replace the fuel filter, then purchase a new seal (#4). I recommend also buying the screw cap (#5). Two reasons: if you are in a rusty area, I've seen those rust. Second if you beat it up during removal, easier to just have a new one. During reassembly I recommend some oil on the o-ring so it seats well, and any kind of grease (bearing, white lube, etc) on the ring when it goes back on.

To remove the ring, you can buy a tool for it - there are many for as little as $15 (check eBay), or you can use a punch and hammer and tap it to break it loose. When you have the screw cap off, you will have to wiggle the filter to break the seal. Just be ready for fuel to come out the bottom side. Once drained, you can reach up inside and pull the pump out, which hangs inside the tank. This can be done by feel, pretty easily in my opinion. The filter and fuel pump bucket use quick disconnects for their interconnects - pretty easy as well.

Assembly is reverse and pretty obvious. When restarting the car, fuel pressure builds pretty fast. If I recall the CAS kicks the LPFP on when you open the driver door, so it is up to pressure when you hit start.

Hope some of this helps you. Remember to manage emptying the fuel - that's the worst of it.

Good luck!

Filippo

Very late but I never said thank you. So thank you for the details, I really appreciate it.

Actually did not go through with changing out the LPFP. Once the temperature had dropped below like 45 degrees, all the weird sounds completely stopped. However, now that the temps are creeping up again the whine has come back but its really only at idle that I notice it, regardless of fuel level. Very odd...wonder if its like overheating. Either way will just continue to monitor for the time being as its just noise.

Thanks again all.

Random edit:
I had some medium-long cranks and slight shudders at idle when I originally posted this that I thought was related to the LPFP but after I got a new battery those issues vanished.