It did seem like there was regression from 510 to 520 to 530.

Make sure you have the latest firmware as much of a pain that is.

I have 510 and 710.

The 710 has WiFi and updates ota so that's a major perk.

Still pretty slow on the e53

Yeah, FW upgrade is painful as I remember, I had to mess with a SD card. But will give that a try later.

Thanks to everyone's help, I have completed the fix. Here are a few things may help others new to this problem.

I didn't removed the center safety belt anchor bolt, but was able to put the seat cushion on top of the seat back over the cargo area to fully open up the space to work on the problem.https://drive.google.com/file/d/16yq...ew?usp=sharing

I installed the o-ring, but didn't do the zip tie fix. This was because in my case, there was no misalignment and I couldn't find a zip tie rated for submerging in gasoline. Also, I noticed that the system is designed to have its plastic rod end pushing on the bottom of the tank and through the spring to apply a continuous pressure to keep the lower portion of the assembly against the top portion. I wonder some of the failures where the o-ring gotten blown out were because the rod end slipped in the tank and started to push side ways causing misalignment between the two parts making possible for the o-ring to be blown out.

For the "taflon tap fix", I did it differently because I don't think I could properly wrap the tap securely to guaranty it does not work loose some how and end up flowing in the gas, eventually clog up something. I used a stainless steel safety wire to tighten the parts together by applying just enough pressure to close the gap while be careful to not crush anything.

https://drive.google.com/file/d/1sxp...ew?usp=sharing
https://drive.google.com/file/d/1yS_...ew?usp=sharing

Finally, I couldn't do the test to actually see if any fuel comes out from those repaired areas. I just couldn't keep the assembly internal to the tank sufficiently visible while still have the external pipe attached :-(

I will just have to drive the gas level down to make sure all is good.

Thanks for all the help again!

Hose clamp around is great fix.

Learn test six I'll let you confirm the fix.

Hmm, not sure why the pics don't show. But here they are if you like to check them out:

https://drive.google.com/file/d/16yq...ew?usp=sharing
https://drive.google.com/file/d/1sxp...ew?usp=sharing
https://drive.google.com/file/d/1yS_...ew?usp=sharing

Ah, that was something I was going to ask. Still don't know what is this test six. I messed around with the NT530, looked at all the different thing it can do, but don't see any test for fuel tank stuff :-(

I also sent a msg to Foxwell about my "no communication" problem, hope they can shine some light on it too.

Test #6 in the hidden menu shows the tanks levels, as Andrew has stated.

If you have a high cluster (variable text message along the bottom of the cluster), watch this to learn how to access the hidden menu: -

https://youtu.be/tdVrXp_RQGk?si=h1AcUl2mIruPggBN

If you have the low cluster, there is a slightly different process: -

https://www.bimmerfest.com/threads/h...luster.432740/

Search YouTube for bmw hidden menu. Very important tool you need to know how to use

Wow, very cool, thanks wpoll and andrewwynn.
That QSilver7 document explains everything.

Interesting what I found on my (actually my wife's) X5.
Running the test with the car not running: 17 13.1 20.1 -> TYPO should be 17 3.1 20.1
After idling for about 3 minutes: 15.9 4.2 20.1
The the right tank value keeps dropping until it settles at: 16.6 3.5 20.1

I wonder why the gas was going back to the left tank after engine stops? Since gas is being pumped out of the right tank to be consumed with any over flow going back to the left tank, I would have thought after the engine stops, the right tank should rise from siphoning. I must be missing something here?

The good think for me is that the fix is working.

2002 3.0 X5 engine stops while driving
 

It's not really "siphon" it's really a venturi pump. It pumps left to right when the electric pump is running.

The two lobes are connected at about 28L and the right side only holds 5L maximum when below 27L total.

Usually the right side will land at 1.4L so yours showing more suggests an aftermarket sender/pump or a bent lever arm. (Bent differently than from new).

I tired to bend mine to calibrate to get to zero that's a very bad idea it read wrong all the rest of the time.

All the BMWs i worked on showed 1.4-1.5L right side when right side was at overflow.

One possibility that I've seen is that during assembly the rectangular float was vertical and held the float off the bottom.

That said you should watch test six and drive down to single digit DTE to confirm fuel senders are accurate.

If you see right side drop before it's baseline before left goes to zero you want to investigate.

When siphon jet isn't at fault the pump wearing out will cause similar symptoms.

I'm curious about the pre-running number that aren't actually possible when everything is working normally. I'm hoping was just a mirage from the car doing averaging. (Or possibly the float sideways)

You should run test 21 which resets the computer including gas averaging but you now know how to use test six which is invaluable for gas supply diagnostic obviously. (Warning it will reset the clock and dashboard mph avg etc)