2002 3.0 X5 engine stops while driving

[kfm]

Originally Posted by cn90

A note for everyone...

After you fix this O-ring issue, to test the siphon pump system, once the fuel level is approaching 1/4, carry a gas can (the stuff you use to fill the lawnmower) in the trunk with 2-3 gallons, then keep driving so it drops to 1/8. This is how you safely test the system w/o being stranded.

On long road trips with gas stations far apart, keep fuel > 1/4 at all time if you can. It is really not fun being stranded in the middle of nowhere. In the city, you can easily get help. In the middle of the corn field, only the cows have sympathy for you.

Yeap, this is what I will do to test！

[kfm]

Thanks everyone for all the replies. The problem is definitely pointing to fuel pump --

I dug out my old generic scanner and found:

Live: DataStream
Fuel SYS1, OL, not ready CL
Fuel SYS2, OL, not ready CL
Error Codes:
P0171 Pd Generic System too lean (bank 1)
P0174 Pd Generic System too lean (bank 2)
P1083 BMW Fuel control limit mixture too lean (bank1 sensor)
P1084 BMW Fuel control limit mixture too lean (bank2 sensor)

When I turn key to run position, I don't hear any sound coming from under the rear seat, so seems like the pump is not running. The noise I mentioned was coming from under the plastic engine cover - I was able to track this down after realizing had the HVAC fun running, turning that off helped. I guess I will worry that later. May be the fuel system is trying to do something without getting enough pressure from the fuel pump. I watch a bunch of fuel pump replacement videos last night till very late, so task today is open up the access to the fuel pump and see if I get any voltage to it and if it is pumping fuel out.

[80stech]

If you do a search on "E53 jet pump (o-ring)" or something like that. you should get a lot of info on that.

[cn90]

Get a gas can and put in a few more gallons.
If your problem goes away, then it is the infamous O-ring.

I used the modified O-ring bought on eBay yrs ago.
I don't think it is on eBay now

[cn90]

The key thing is finding the O-ring a tiny tiny bit bigger than the factory O-ring.

All info is in this DIY I wrote back in 2018...

https://xoutpost.com/bmw-sav-forums/...flon-wrap.html

[kfm]

Originally Posted by cn90

The key thing is finding the O-ring a tiny tiny bit bigger than the factory O-ring.

All info is in this DIY I wrote back in 2018...

https://xoutpost.com/bmw-sav-forums/...flon-wrap.html

Yes, I read through your post, that was what gave guts to try pull the sender side apart! Thanks for that!

Where did you find the larger o-ring? Do you remember the size? I can't measure from the broken one...

[cn90]

Also,

If you don't have time/desire to fix this issue, then keep fuel level > 3/8 at all time.

[kfm]

It took some doing to open up the sender side. The plastic part is semi-transparent especially if I shine light onto it, so I can clearly see the o-ring through the plastic. It looked perfectly seated in its grove, nothing like what was shown in the pictures posted on-line. I was very baffled and decided to take the thing apart anyways. When I pulled the pieces apart, the o-ring just popped out of the grove! Turned out, it was broken. So even still seated nicely, it was no longer air tight.

Onto to ordering replacement o-ring and putting everything back.

Thanks to all the replies to my posted and guided me to this fix!

[80stech]

Did you check with the pump running if the O-ring was leaking ? You should be able to get away with the same size and a few wraps of teflon tape as well. I think the o-ring is usually pushed out if it has failed. Sometimes the lower part which is a plastic to plastic fitting can leak too which you could see with the pump running.

[kfm]

I found this on Amazon, figured one of them should fit :-)
I am thinking either the 22 or 23.5mm ones.
The o-ring grove measured 23.38mm, a very strange size.

Ah, didn't check with pump running, but now I already took it apart :-(
But does the pump send fuel back to the sender side?