Fuel Sender Replacement
Recently, I noticed that my fuel gauge would act strangely. When I filled up my gas tank, I would start the car, and the gauge would read that the tank was only half-full. A few taps on the face plate would result in a wildly erratic needle that would dip down to empty and then shoot up to nearly full. At first, I thought that the gauge wasn't grounded properly, but I checked the ground in the trunk (by the gas tank) - that wasn't it. I checked the grounding strap in the engine compartment - that wasn't it. I pulled the instrument cluster out of the dash and checked the grounds behind the cigarette lighter - they were tight and good. Since the gauge was already out of the car, I inspected it very carefully and came to the conclusion that if the problem was in the gauge itself, that I would have to send it to VDO.
After living with this condition for several weeks, I had the opportunity to go visit Phil Marx at the Bavarian Motor Warehouse in Charlottesville, VA. I looked around his store (that's a great story in itself), and after we talked about various BMW topics (sheet metal, rust repair, price books) I asked him for his opinion of my situation. Immediately he said; "Fuel sender" and we went to work getting the old unit out of the gas tank so that we could take a look. BMW has a special tool for removing the fuel sender, and Phil of course had that tool. First , you need to disconnect the electric leads to the top of the sending unit. Next, using the special BMW tool, you turn the sender counterclockwise until it pops off of the O-ring. When we pulled the sender out of the gas tank, it was missing the filter and the 5.5 millimeter nut that holds the unit together was lost somewhere in my gas tank!
Upon closer inspection, the electric contacts had come apart and the wire that surrounds the float was severed and useless. We put it back together as best we could and I drove it back home. The next Monday I ordered a new fuel sender from the local BMW dealer and by Wednesday it had arrived from the warehouse in New Jersey. After a quick disconnect of the old unit, and seating the new sender in the gas tank and reconnecting the electronics and fuel line, I had a brand new fuel sender in my tank and my gauge is now as steady as a rock. When you are ordering the sender (Part #: 62 16 1 353 239 for 2002s before 74; #: 62 16 1 358 097 for those after 74), check with discount resellers but don't ignore the local dealer because of prcing issues. A brand new unit will cost somewhere between $90.00 and $120.00. If you're going to buy a used fuel sender, make sure that the float wire is in one piece and connected to the contacts, make sure that the filter is in the bottom of the suction tube, and make sure that the unit is securely bolted together. When you are in the process of removing or installing the sender yourself, you can use 2 long flat-bladed screwdrivers in an x pattern to turn the unit. However, please use caution when doing this because it is very easy for one of the screwdrivers to slip, which may cause you to take a big chunk out of your hand. I know this from personal experience. All in all, the whole job should take you 5 minutes.
Note: When you remove the sending unit it's a good idea to replace the gasket to prevent fuel leaks. When doing this, coat the new gasket with Vaseline before you install it. --Ware