Engine misfires while fuel gauge comes down to 1/4

[sfcl]

Hi all,

I have a strange problem with my 3L X5, the engine misfires while the fuel gauge comes down below 1/4, just like it misses fuel. No problem from full to 1/4. I've chzecked the fuel gauge and it seems to be ok (I add 60 liters to get the full tank when the gauge indicates 1/4). Any idea welcome!

Thanks in advance

[tklass]

could be the intank pump, you may want to check the fuel line pressure when you get to the point of failure.

i had a very simular problem with my 06 turned out to be the pump in the tank.

[sfcl]

Thanks for the reply. Very interesting as I wasn't aware that a worn fuel pump can pump the fuel only when the tank is full and not whan the level is low. I'll let you know what I have found.
Best regards,

[lp01]

Hi all!

I'm having exactly the same problem. When fuel level goes down ~1/4 i can see some air bubbles in the fuel line, and the engine just misfires when accelerating hard.

Did have you found out what happened sfcl?

Does anyone know what else could it be besides the fuel tank pump?

Cheers,

lp01

[chuk01]

I struggled for 5 mons with this issue and after countless $$$$ at the stealer, it was the in tank fuel pump!!!! Despite my usual professional demeanor, military guy, I lost my F$$^king mind at the dealership. I would suggest taking it to "Your Guy" and having him replace it. Don't loose your "Military Bearing" on the floor of the Stealership!

[sfcl]

Originally Posted by lp01

Hi all!

I'm having exactly the same problem. When fuel level goes down ~1/4 i can see some air bubbles in the fuel line, and the engine just misfires when accelerating hard.

Did have you found out what happened sfcl?

Does anyone know what else could it be besides the fuel tank pump?

Cheers,

lp01

Hi, the problem was only a small o-ring! The vehicle has two sides to the fuel tank. The driver side has the fuel level sensor and a siphon jet pump. The siphon jet allows fuel to be transfered to the passenger side of the tank.
If you remove the driver side unit there is a plastic structure attached to it. There is a release to remove it. in here you will find an o-ring. If this O-ring splits then it will not allow all of the fuel to transfer over to the pump.This is because it sucks air instead of fuel.

Much cheaper than a whole pump!

[lp01]

Thanks a lot for your fast replies and wise advices.

I guess I'm about to avoid spending some heavy $$$ on expensive repairs and a similar amount to compensate dealer's bruises

Cheers