Alanw1992

Hi new to the page need some help
Got a 525d and fitted a new fuel pump in tank and everything going was great in till used all the fuel from right side and all went to left side can't Figure it out had about 3 pumps now do I have to reprogramming something or reset engine management and how does.it lift fuel from left side to right thanks

jtbgonesailing

Sounds like you didn't get the plumbing reinstalled properly. Need to check the plumbing in the left fuel cell by the fuel filter. There are return lines from the left cell to the right that enclude a scavenge return line. This particular line, feeding from the fuel pressure regulator, also scavenged fuel back to the right cell. This prevents the right cell from running low and starving the engine for fuel, while there is still fuel in the system. Have a look at these connections in the left cell.

You have a diesel, so the assembly in the left side doesn't have the filter built in. As you know you have an external filter assembly. The attached thread is on a gas fuel filter changeout, but it has a photo of your assembly that is located in the left cell. If you look closely at that photo, you can see, there at the electrical connector, there is the attachment for the fuel return line, to the right cell, that contains the scavenging assembly.

https://5series.net/forums/diy-do-yo...t-swap-121415/

Good luck and I hope this helps.

Alanw1992

Hi thanks for reply I haven't messed with any pipe work by the fuel filter this one work with 3 pipe from main pump in tank run in tank to the sender unit one pipe is a flat connect with like a hole in bottom of it and over Is to push fuel up to the engine this one is like mine
http://www.ebay.co.uk/itm/2004-BMW-530D-E60-3-0-DIESEL-FUEL-PUMP-SENDER-UNIT-IN-TANK-0580303043-306D2-/322389601740?fits=Car+Make%3ABMW%7CPlat_Gen%3AE60& hash=item4b0feaedcc:g:aFQAAOSwEzxYeQFg

jtbgonesailing

I edited my post to enclude a link that may help. Sorry I wasn't fast enough getting it up...

There has to be a return line from the left cell to the tight. Look at the photo of the assembly for the diesel unit in the left cell.

The flat connector with the hole in the bottom is the line that attaches to the unit in the left cell. That is your scavenger line to draw fuel out of the left cell.

Alanw1992

Yes that was I thought it was how does that work I can't really get the pipe work wrong in that flat connection there 2 little holes were fuel comes in and ment to go out to the other side


Also just put another 10gallon of fuel in and the milage on display stayed the same.if.i move the sender Manual it goes up and down fine could this be anything to.do with the fuel pump relay or fuel pump modual because just check and seen its a second hand one with e90 write on it

jtbgonesailing

Think you need to determine if you have the proper replacement parts installed now that you are talking about used parts from other model BMWs. Try going to: realoem.com Enter your vehicle vin number and work your way down to the fuel system. Identify the parts you are replacing and compare the parts numbers listed in realoem and what you removed. Do those part numbers agree? Now compare the use part that you installed, is that part number listed as a replacement part for your car? Used parts are always a flip of the coin as to wether they will in fact work properly, even if they are the proper part number called for.

You talk about putting more fuel in the tank and moving the float lever. There are to two float sending units, one in each cell. I think the left cell sending unit shows as 1/2 to full cell and the right sending unit with the fuel pump shows 1/2 down to empty.

When you replaced your fuel pump with the used replacement pump, did you also open the left cell and disconnect the fuel line and electrical connector from the assembly?

Alanw1992

Hi thanks for reply yes I had to disconnect the left side and pull the pipes out from the right hand side and reverse to install

The part number on the pumps I'm using are the same as the old one which come off the car first one that one seized up
Some one else had told me could be the relays because my first pump seized up there say the pump could be running full all the time could this be right

jtbgonesailing

To degrees, I thought your problem was/is, the fuel system was running out of fuel in the right cell with fuel remaining in the left cell. You've confirmed the used replacement fuel pump is the same part number as the original, good. If the replacement pump is working correctly, which it appears to be by virtue your engine runs as long as there is fuel in the right cell. I go back to my statement, believe you have a problem with your plumbing. The fuel line connections in the left cell, that returns fuel to the right cell are not connected properly or there is a problem with that line on the replacement fuel pump....

Alanw1992

Yes I think there something wrong with the connection on the left cell but can not find it I've check or splits on pipe work and blockages there isn't any if I blow down the return on the left cell it just blows bubble does not push anything to the right cell I need a diagram or pics.of how it works thanks

jtbgonesailing

Ok good.... You are in the left cell and have confirmed the line is clear. Look at the link I referred you to above and post number 22. This assembly in the photo in post 22 should be identical to your unit in the left cell. There are two lines from the fuel pump that go into the left cell. The line you blew through attaches firmly, with a click, to the bottom of the assembly in the photo and the electrical connector attaches there as well. If that line is not properly secured to the assembly, you will never get fuel back to the right cell. The second line, with the female quick connect assembly provides fuel pressure to the assembly in the left cell. The fuel travels through the assembly and out the bottom and to the line you attached at the bottom connector. The holes in that connection, allow fuel to be drawn into the return line, by a Venturi effect, scavenging fuel from the left cell and passing it to the right sell. Now the second line, with the quick disconnect fitting, attaches to a male connector towards the top of the assembly or bottom, hard to tell in the photo, believe it is there at the bottom, sorry. As long as you have the two lines attached as described, fuel will be transferred from the left cell to the right while the engine is running.