Fuel Tank doesn't get filled up most of the time

[TurboHank]

Wondering if you guys have had similar problems. I noticed that everytime I go refuel my Z at a gas station near my house, only at a particular pump in that station would the fuel gauge reach the 100% full mark. If use a different pump in the SAME gas station, I would get about 90-95% full reading on the fuel gauge. Similarly, when I venture out on trips, and refuel, the fuel gauge would also read 90-95% full.

I always use the latch on the fuel handle to let it fuel automatically.

Anyone has noticed this?

[Mr. ///M3 RD]

Originally Posted by TurboHank

Wondering if you guys have had similar problems. I noticed that everytime I go refuel my Z at a gas station near my house, only at a particular pump in that station would the fuel gauge reach the 100% full mark. If use a different pump in the SAME gas station, I would get about 90-95% full reading on the fuel gauge. Similarly, when I venture out on trips, and refuel, the fuel gauge would also read 90-95% full.

I always use the latch on the fuel handle to let it fuel automatically.

Anyone has noticed this?

Some times an air lock in your tank will stop the pump prematurely as you properly know. I just mention it here for clarification.

I would carefully continue filling until I know the tank is full (slightly overfilled). Then check your gas gauge and if it does not show FULL 100% I would go to my dealer, explain what I did and let them fix your gas gauge.

Hope this helps

[TurboHank]

Rolf-D thanks for the response. But the interesting thing is that at the gas station (near my home) that I go to most of the time, only one pump (always the same one) out of six, gives me a full fuel gauge reading. I tried all other 5 over time, and none of the other 5 gets my fuel gauge to the 100% mark... Super weird.

[Vel]

Just do what I do - stick the pump in all the way into the tank and let it fill. When it's done, pull it out a few inches, and continue filling until it stops again. Problem solved.

[Silver-Bolt]

Run it on the slowest setting. The faster you pump in fuel the more turbulance you create in the tank that can trigger the nozzel to shut off as if the tank were full.

[Mr. ///M3 RD]

Originally Posted by Silver-Bolt

Run it on the slowest setting. The faster you pump in fuel the more turbulance you create in the tank that can trigger the nozzel to shut off as if the tank were full.

I wonder if that sixth pump is the farthest away from the tank and as a result the pressure is slightly less Hmmmm I guess he needs to line up at the sixth pump or try the slower pump routine you suggested

[Memphis1]

Is the pump older or newer then the rest, might be the length of the nozzle or whatever you call the barrel. a lot of the new pumps have longer nozzles and dont top off the tanks, which technically speaking is good, think about a really hot liquid when your wife puts it in a blender she has to leave a lot of space for expansion otherwise it will explode the lid off. Same concept.

[TurboHank]

Originally Posted by Memphis1

Is the pump older or newer then the rest, might be the length of the nozzle or whatever you call the barrel. a lot of the new pumps have longer nozzles and dont top off the tanks, which technically speaking is good, think about a really hot liquid when your wife puts it in a blender she has to leave a lot of space for expansion otherwise it will explode the lid off. Same concept.

Yea I am going to check the length of the nozzles of the pumps at that gas station next time to see if the one pump that always gives me a 100% fuel gauge reading have the shortest length. Who says longer is always better?!

[riccis]

Have had the same problem. But I find that it also depends which pump/petrol station I use. Some give me less problems than other, probably due to the pump design and/or fuel rate flow. I have noticed, however, that the issue is mush less pronounced now that when I first got the car.

Have a look at this thread which I started some time ago. You're not the only one to suffer.

http://e89.zpost.com/forums/showthread.php?t=326009

[tranquility]

A question a bit on the tangent: how exactly does the pump know when to stop filling?

[marcw]

In Oregon we aren't allowed to pump our own gas. Guess I won't be very helpful on this thread

[TurboHank]

Originally Posted by riccis

Have had the same problem. But I find that it also depends which pump/petrol station I use. Some give me less problems than other, probably due to the pump design and/or fuel rate flow. I have noticed, however, that the issue is mush less pronounced now that when I first got the car.

Have a look at this thread which I started some time ago. You're not the only one to suffer.

http://e89.zpost.com/forums/showthread.php?t=326009

thanks, good info here. Going to pay attention to the pumps which gives me a 100% reading next time.

[Mick70]

(1) The pump's nozzle knows that the tank is full if it "becomes wet" = if the level in the filler's tube rises up to the top.

(2) Switching off too early on all or even certain pumps is most presumably NOT normal behaviour. I had the same issue with my E89, together with some other guys in a German forum. BMW then made up a PUMA case (sorry, don't know the PUMA number) and let the dealership change the complete tank and filling tubes (hrmpf - this required removing the rear axle and everything - major surgery, took 4 weeks last summer altogether). Finally it turned out that it was just the filter of the tank's venting that was too tight so that the air in the tank could not blow out fast enough when filling in new fuel ("cavitation")... Now, after the repair everything is fine on 95% of all pumps.

(3) Workaround (similar to Vel's suggestion): Try to pull out the pump some inches and turn the nozzle 90° to the side or even 180° to the top right from the beginning or if the pump turns off. In this configuration the air in the tank can stream out better through the filling tube.

Best regards

Mick

[big-server]

Just rotate the pump when you filling.
Because the air-sensor is located bottom side of the pump's nozzle.
I always do it and I don't have any problem.
(rotate 45 to 90 degs.)

[mcbeee]

Originally Posted by big-server

Just rotate the pump when you filling.
Because the air-sensor is located bottom side of the pump's nozzle.
I always do it and I don't have any problem.
(rotate 45 to 90 degs.)

Good tip

I have that problem with one pump out of 8 at my local station but only on my truck, the Z4 I fill slowly at the top and to the brim every time.