Originally Posted by neurodoc

<Hi there!
on my bike the problem is the fuel indicator (AKA "fuel strip") in the tank.
Two years ago, while on the road, I started getting erratic readings about the amount of fuel in the tank. BMW blamed some additives in the fuel that may have short circuited the "strip", and replaced it for a new one at no charge. One year later, readings got erratic again. BMW guys said they would replace the strip again, as it was under warraty. Two days later they phoned to say they needed some more time cause they had changed the strip 3 times (2 were new and one from another bike) and none worked. A week later they still did not find out what was wrong. 10 days later they said it was my fault because I had too much "non original stuff" on the bike (one HID lamp, two PIIA halogens, and a set of Hella horns) causing the wiring to fail. As none of these accesories were connected directly to the wiring, but to the batt by means of relays I did not buy their "diagnosis", so I told them to disconect the fuses from these parts and to test the strip again.... AS EXPECTED IT DID NOT WORK!
A long weekend approached, As I had in mind to make a short trip on the bike, BMW returned it to me promising to continue the repair upon return. When I left the shop, the indicator was as dead as when I brought it in. The next day, after refueling it started doing some weird readings..... at the end of the day it was working propperly again. (??!!) 8 months have passed since and the readings from the strip are still quite accurate. BMW guys have no idea why it does work now.... and offered to take a look, but I didn´t let them! I know it will fail again, probably when I need it most..... but what else can I do?

Originally Posted by tonylester

there has been a problem with the film type sensors and it is a well known problem within BMW, in the UK at least. I would not believe your dealer in him saying its your fuel or your 'non original stuff' unless it is directly connected to the fuel sensor wiring it should not cause a problem. It is a far overengineered design with one heater wire and one reading wire, the heating wire warms up and the reading wire changes resistance depending on how much fuel is in the tank. BMW has since updated the part but there was a time, probably when you went in for your second sensor, when the parts were coming from the factory faulty, we in the uk were told to test the parts before we fitted them with a multimeter to check whether they are part of the faulty batch. The new sensors seem much more reliable now. We have had a few customers come back for 5 or 6 sensors where we would fit new ones and they would fail a few months later. When we fit a new sensor we always tell the customer to go and fill their tanks as this fully teaches in the new sensor and the new sensors take a small roadtest before they register so if the guy that replaced your sensor didnt go out on it then it might be why you erratic readings when you picked it up.
BMW are slowly getting rid of the film type sensor for the more reliable lever type. They have removed the sensor completely from the r1200r model so it doesnt actually have a fuel sensor on that model also all the new models that will come out in the future will be fited with float lever sensors.