Fuel Tank Sensor - D-Sport 2005

X5-D-Sport · Post by **X5-D-Sport** » Tue Sep 28, 2021 11:32 am

Hi People,
my D-Sport ran VERY low on diesel recently, & now.... even with £100 of diesel onboard the dash needle reads ZERO & the fuel light is on.
AND
if i drive for more than 260 miles... after the tank filled to the neck, it runs out of fuel & stops.... even tho there is another 200+ miles of fuel on-board, & will only be re-started with a gallon put back into the tank.
This hints at one side of the tank fuel sender reading empty & pumping fuel to the other side of the tank

SO, a few questions to you guru's out there.... does it have a float on an arm, or a cylindrical vertical sliding float.
I understand there is a level sensor on each side of this tank, as it is a saddle tank straddling the Prop-Shaft.

So, before I yank it all to bits & get fuel splurting every where, does any one have knowledge of the fuel tank system set-up & what the likely cause issue is ?

Could it be a simple fuse blown....
Could it be a fuel float managing to get stuck under one of the many pipes inside the tank ?
or some thing else

any help much appreciated.
regards
Grant B

X5Sport · Post by **X5Sport** » Tue Sep 28, 2021 6:23 pm

Sounds as if the transfer pump between the two parts of the tank is faulty.

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X5-D-Sport · Post by **X5-D-Sport** » Tue Sep 28, 2021 8:39 pm

I was wondering this.... but that would not explain why the fuel level indicator at the display cluster stayed at Zero ever since the vehicle was run to empty... with 550miles from the previous fill & 30 miles below its zero miles remaining.

My theory was, that the big side of the tank also has a level float, that is jammed under a pipe, & thus fuel is always pumped from the filler side of the tank to the other side, thus causing the filler side of the tank to run dry after 230 miles & the vehicle stop.

If the large side of the tank was running dry from use, then I would get 300 miles from it easy..... just pondering...
AND
ever since the 550 miles use before a £110 re-filling leads me to think that a float has got tangled on tubes inside the tank itself, as there are loads of them strewn around in the tank - a lot more than the diagram actually shows..
AND
the fuel tank level ALWAYS reads empty...

Wayfarer · Post by **Wayfarer** » Wed Sep 29, 2021 8:21 am

Know nothing about BMW fuel systems but could it be that if the fuel gauge is saying empty then that stops the transfer pump operating to stop it pumping dry, so once the small tank is empty it’s empty? Just a thought.

X5Sport · Post by **X5Sport** » Wed Sep 29, 2021 12:55 pm

Stick a variable resistor on the float output and see if that changes the gauge perhaps? Sounds as if there's an issue with the sender in terms of level but that doesn't completely explain the other part about the tank being full but the range is significvantly less (and you aren't puffing smoke like a steam train from the exhaust!!) unless the pump system does prevent run-on-dry?

From memory access is all under the back seat base. Worth checking in case it's a squashed wire, but I think that's less likely. Stuck float is defo worth a squint at though given it's all happened after a 'dry event'. Could also be crud in the link pipe for the jet pump?

X5-D-Sport · Post by **X5-D-Sport** » Wed Sep 29, 2021 2:16 pm

yes agreed Richard.
I have another issue that all the pipe couplers are the crush connectors that squeeze the pipe to the connection points.... NOT quick release connections unfortunately.... which make it a real ball-ache to get the pump out of the tank...

Yes, all was well until running 550 miles out of a tank of fuel... it drove for almost 30 miles AFTER it said empty & into a gas station, since then it has always read EMPTY at the cluster.

X5-D-Sport · Post by **X5-D-Sport** » Thu Mar 31, 2022 5:15 pm

hello again people,
I am wanting to rejuvenate this post in case some one else has suffered the same issue.
the vehicle gets to empty after about 230 miles & will STOP.

so, a recap.
about a year ago it was driven to about 560 miles & 30 miles AFTER it claimed to be empty.... this was due to a diesel shortage & hunting for fuel.
So, the fuel system was working properly at this point.
I then put about £50 of diesel into the tank, & it read EMPTY, when it should have been half full.
So I added another £50 approx. of fuel to top it up to the filler neck.

It still reads Empty, & the vehicle ran out of fuel & stop when 240 miles were used.
Meaning, it defo has half a about 1/2 a tank remaining & still runs dry.
whenever I fill the tank, I can only get about £60 in the vehicle to fill to the neck.... meaning the tank is always already just under half full.

The X5 has a saddle tank that straddles the rear prop-shaft.

So firstly, I am curious as to which side has the fuel pick-up - Right or Left. ??

I am trying to apply some logic here...... to work out which part has failed....
the failure will most likely be one or other of the tank float sensors - & there is one in each side of the saddle.
My guess is that it is one of the fuel level sensors...
AND
because the tank was run to almost dry at 550 miles, says to me that the floats on BOTH sides of the tank float sensors ended up on the floor of the tank...

This also says to me that.....
the side with the pickup is not the side with the float failure, as i would always get some 500 miles per fill as the fuel would be pumped to the pick-up side of the tank...
As I only get approx 230 miles before the vehicle stops due to lack of fuel, the side of the tank WITHOUT fuel MUST be the fuel pickup side & the opposite side MUST be the side that is almost full has the float that has failed or gotten jammed at its lowest position, hence all avaiable fuel is pumped to this side.

So, which side is the fuel pick-up on the E53 diesel sport...?
Any one know, before i pull it all to bits & get fuel everywhere lol

StuBeeDoo · Post by **StuBeeDoo** » Thu Mar 31, 2022 6:18 pm

According to BMWFans version of ETK, there are two level sensors/pick-ups, but only one incorporates a pump. My money's on your problem being a blockage in the pipework from the side opposite to the pump. The pump is emptying the side it is on, but can't draw fuel from the other side because of the blockage.

Therefore, if you pull both the sender units out of the tank, the one that doesn't have a pump is the one that will likely have two faults - blocked supply pipe to the opposite side, and float arm stuck fully (or nearly fully) down. From the orientation of the image, I would pull the left-side unit first - but beware............ If it is the correct (ie offending) one, it will be nearly full of diesel.

Leslie · Post by **Leslie** » Thu Mar 31, 2022 7:52 pm

It fills in the right side and goes out the left side I think if its like the e70

(you could see which tank is full or empty when you run low on fuel by taking the covers off) which means the fuel in the right side isn't getting over the hump in the centre , when you fill it the right side will spill over when filling and driving and fill the left but the right side will not flow over once below half full as it can't go uphill. Id think the transfer pump that moves from right to left is faulty ,maybe it overheated while running with no fuel for quite a while and blew a fuse ? That would explain no level reading but may not be the problem in this case . The diagrams may refer to USA cars which might have the fuel pump and filter on the opposite side so may well not be right for a uk car confusing things further

The info above suggests the fuel level is determined by adding both levels left and right together but you are getting no level at all as none are reporting back rather than just one , this also seems like one fuse covers both as with one working it should only be possible to get a half full reading at best no matter how much fuel you put in.

X5-D-Sport · Post by **X5-D-Sport** » Thu Mar 31, 2022 8:58 pm

Many thanks Leslie... Good information.

Becaise everything was working perfectly until the tank was totally empty, so i am presuming that if as it seams the right side of the tank is mostly full of fuel & the pick-ip side is running dry, then the float is potentially trapped under some of the intetnal tank pipes, the tank then thinks it is empty that side.... & keeps pumping fuel from tbe pickup side/left to equalize both sides.....

So, in theory.... the right side of the tank level sensor is trapped & once released iy will all wotk properly (with any luck)

Leslie · Post by **Leslie** » Thu Mar 31, 2022 10:31 pm

Get the lids of for a look when the fuel is next low

henrym3 · Post by **henrym3** » Mon Apr 04, 2022 11:02 am

If you access the hidden menu it will tell you how much fuel is in each side, google hidden menu for x5 on how to access it. Sounds like the suction jet pump isn’t working to transfer from one side to the other where the fuel pump is. From my reading this is generally a failed "o" ring on the suction jet pump which can be replaced. Probably £200 plus at BMW or 50p if you diy

X5-D-Sport · Post by **X5-D-Sport** » Mon Apr 04, 2022 11:13 am

Aha... Henry... long time no speak Sir.
I hope you are well.

I have just had ANOTHER dose of Covid & still alive..
Just lol.

O am goinh to shove my arm in the tank later this week & have a poke about too..

The O ring sonds like a possibility for sure.

I need this fixed as i have only 220 miles between fills at the moment & am sick of lugging 300 miles of fuel around that i cannot uses lol

henrym3 · Post by **henrym3** » Mon Apr 04, 2022 12:31 pm

DIY: E53 X5 Siphon Pump with Improved O-ring and Teflon Wrap
Well that link hasn’t worked. Must improve computer skills.

henrym3 · Post by **henrym3** » Mon Apr 04, 2022 12:41 pm

https://www.xoutpost.com/showthread.php?t=109180
You could copy and paste that into search

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