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View Full Version : Replaced Right Fuel Tank Sender (Sensor)


wjjklj
06-18-2012, 08:56 PM
I have been getting random low fuel warnings when the tank is far from empty. I read that if you go into the hidden menu and look at the ADC values and see that a sensor is higher than 450 ohms then that sensor is bad. Then sensors should have fairly close readings on the left and right if working correctly. I troubleshooted my bad sensor to be the right side (passenger). So I ordered a sensor from thebmwstore for $75.82 and replaced it myself. These are the steps I took:

1) run the fuel almost empty.

2) unplugged negative battery cable.

3) removed back seat. Just pull up on the seat firmly.

4) remove the rubber cover over the fuel tank on the side you are replacing.

5) remove the round rubber plug underneath the first layer rubber pad.

6) remove the (4) 10mm nuts on the round metal plate over the fuel pump and remove the plate.

7) unplug electric connector

8) remove black fuel line connector gently by squeezing side tabs. Have paper towels to absorb any gasoline.

9) remove the blue fuel line by squeezing the connector sides. Remove it just enough to bleed off pressure. Some gasoline will come out so have paper towels around it. I had to do this about 7-8 times soaking up the gasoline until the pressure was released.

10) have a helper hold down the white tab facing the front of the car with a large screwdriver so the fuel pump does not turn.

11) use another large flat screwdriver and a rubber mallet to unscrew the metal ring holding the fuel pump in the tank. Hit it counterclockwise.

12) once the metal ring is loose remove it. Then lift the top of the fuel pump off and place to the side still connected.

13) reach into the tank and pull up on the fuel sender and unplug from the fuel pump. There are two tabs on either side of it that you just squeeze and pull upward.

14) replace with new fuel sender (sensor). It has a slot that it snaps down into that only goes one direction. Pay attention to what it looked like before you removed it.

15) complete reassembly in reverse.

This entire process took about 45 minutes with most of the time taken to soak up the fuel coming out of the fuel lines when I pulled them off the fuel pump. Again I just pulled up on them a little a time and they leaked a little. I then soaked the gas up with paper towels. Don't just pull off the fuel line all at once because they are under pressure. Be very careful at this step and have no open flames or cigarettes around. Perform this at your own risk. Obviously you are working with gasoline and can kill yourself if you are not careful.

This was an easy repair overall and the same procedure would apply if replacing your fuel pump. This is much better than dropping an entire gas tank off the vehicle like I had to do recently on my Lincoln Navigator just to replace the pump. I took some pictures too. I hope this helps somebody.

bmw74me
06-18-2012, 09:50 PM
Well done man .. Thank you for sharing ...

***CCCP***
06-19-2012, 02:44 AM
Amazing work man. Good job. We should sticky this on or put it in diy section.

1bad540
06-19-2012, 07:25 AM
wow awesome, actually have to drop my car back at the dealer for this, prob one of my last trips under warrty.

wjjklj
06-19-2012, 07:50 AM
I copied the post over in the DIY section. Thanks for all the kind words everyone. There are many things on this car that I am sure are way over my head but I am amazed at what I have been able to fix when I research and try hard enough. The design and the engineering makes most things pretty straightforward.

1bad540
06-19-2012, 08:39 AM
Thats what great about Bmw's they are made to be serviced easily. its the difference between an engineered car.

First_745Li
06-20-2012, 07:35 AM
I just checked my ADC value and it's 473/474 ohms, and I have been getting the fuel level low indication.. I guess I should look at changing the fuel tank sender as well. Thank you for the write up wjjklj.

wjjklj
06-20-2012, 02:50 PM
It depends on how full your fuel tank is. I noticed that my right sensor was very high and my left was much lower when at half full. At full tank they both showed about 460 ohms so I don't know. If the both show close to the same amount of ohms might be something else. I will report back if I get any more low fuel warnings.

First_745Li
06-20-2012, 06:29 PM
Ok thanks. When I checked I had almost a full tank. I'll eventually change it anyway.

wjjklj
06-21-2012, 08:41 AM
Check it when you have about half a tank and see if there is a large difference between the sensors then.

First_745Li
06-29-2012, 09:01 PM
Check it when you have about half a tank and see if there is a large difference between the sensors then.

Ok I checked the ADC values when it was at 1/2 tank, 472 ohms..
I think I might end up changing the sender at some point.

wjjklj
06-29-2012, 09:42 PM
Ok I checked the ADC values when it was at 1/2 tank, 472 ohms..
I think I might end up changing the sender at some point.

Yes, it looks like a bad right tank sensor (sender).

First_745Li
06-29-2012, 09:46 PM
Yes, it looks like a bad right tank sensor (sender).

Thanks for the DYI write up.. much appreciated

1bad540
06-30-2012, 07:25 AM
Just got my car back yesterday for this, i think they chnaged both sensors. heres a vid of what my car was doing.

wjjklj
06-30-2012, 10:42 AM
Just got my car back yesterday for this, i think they chnaged both sensors. heres a vid of what my car was doing.

Yes. That is exactly what mine would do occasionally. It would happen even if the tank was full.

1bad540
06-30-2012, 02:06 PM
Looks like they changes the right sensor and a fuel pump fix kit?

wjjklj
06-30-2012, 02:15 PM
Looks like they changes the right sensor and a fuel pump fix kit?

I just replaced the sensor and it fixed the problem for me. Not sure why they did both. Maybe since you are still under warranty and the fuel pump was easily accessed they just went ahead and did both.