The Schader Family


Balloon Ride Autos MB Trips Projects

MB 300SL Tesla Toyota Sienna Fuel Sensor Timing Chain

Fuel Sensor Cleaning
Click on the pictures to get a larger view in a new browser window. Close that window to return here.

I decided to tackle the erroneous fuel reading which always showed over 1/2 full when in reality it was empty. I suspected that the resistor pattern on the sending circuit board was bridged with a conductive material reducing the electrical resistance. This 'bridging' was due to an additive in Shell gas about a year ago. Shell claims that they do not use this additive anymore but I now rarely use Shell.

True to my suspicions, when I took a reading after removing the unit from the gas tank, an empty reading was only 500 Ohms instead of the 1000 as per the shop manual. Vigorous brushing with a toothbrush and engine cleaner restored the resistance as per specification.

Access hole in back middle of trunk for removing fuel module
Fuel module removed. This contains the fuel pump and fuel level sender.
Close-up of fuel level sending unit. As per manual, an empty tank reading should be a resistance of 1000 Ohms. It was only 500 Ohms which substantiated the 1/2 full tank reading when empty on the gauge in the instrument panel.

After scrubbing with engine cleaner, resistance was back to 1000 Ohms and gauge reflected correct fuel level.