Fuel sender

[ralphsanders]

Hi the fuel guage keeps jumping around one min no fuel next half a tank. Having looked on the forum one of the many faults with the 2001 c class is the tank sensor. has anyone had the same problem and is it easy to fix(i.e diy) and what likely costs.

Thanks:bannana:

[philharve]

Hi ralphsanders

I don't have your particular problem but I have noticed odd behaviour with the fuel gauge in my car. I prefer to cross check fuel readings with the odometer as a safeguard. I don't want to run out of fuel unexpectedly.

There are two fuel measuring systems in the W202: a float sensor which controls the fuel gauge needle and a thermistor to control the 'low fuel' lamp. Your problem appears to be associated with the float sensor and/or circuit.

The thermistor is a solid-state device situated near the bottom of the tank. It's an electrical resistor that is cooled by the petrol sloshing around. When the petrol level is low the thermistor heats up and its resistance falls permitting more current to flow through it. It's this increasing current that lights the lamp. It takes the thermistor around 5 minutes to respond to changing fuel levels but once stable (car parked) it is very accurate.

My guess would be you have a faulty float sensor which is easy to replace. I have no idea as to cost.

REGARDS Phil