C5 Fuel Gauge

[acrowot]

Had this 2001 2.0 hdi SX C5 for 2 weeks now, done various jobs on it and it is improving, the latest fault to appear is when I bought it the gauge showed just under 1/4 full and the display said 67 miles remaining drove it home 32 miles the tank empty light was now lit and display showed 27 miles, filled the tank full, gauge showed full and display 402 miles this went up to over 600 when on a motorway journey, after a few journeys the gauge went down to 3/4 full and the display showed aroun 400 miles on using the car round town. The gauge now shows full and the display shows between about 350 and 500 miles depending on type of journey, the mileometer now shows 200 miles and the gauge shows full.

[Duracell]

Not sure about the last bit (full and 200miles) unless you mean the 'miles since last reset' which will just keep accumulating unless you reset it by pushing and holding the button on the end of the right hand column stalk. The remaining miles displayed are calculated using the current average MPG and the fuel remaining in the tank, so will reflect the type of driving you are doing. That bit appears to be behaving normally.

Richard

[acrowot]

Not sure about the last bit (full and 200miles) unless you mean the 'miles since last reset' which will just keep accumulating unless you reset it by pushing and holding the button on the end of the right hand column stalk. The remaining miles displayed are calculated using the current average MPG and the fuel remaining in the tank, so will reflect the type of driving you are doing. That bit appears to be behaving normally.

Richard

The 200 miles on the mileometer is the mileage done since the tank was filled up, I reset the trip on filling the tank.

[acrowot]

Not sure about the last bit (full and 200miles) unless you mean the 'miles since last reset' which will just keep accumulating unless you reset it by pushing and holding the button on the end of the right hand column stalk. The remaining miles displayed are calculated using the current average MPG and the fuel remaining in the tank, so will reflect the type of driving you are doing. That bit appears to be behaving normally.

Richard

The 200 miles on the mileometer is the mileage done since the tank was filled up, I reset the trip on filling the tank.

The problem is if the gauge is reading full does the ecu think it is full when doing it's calculations, I was thinking maybe the float in the tank was faulty, where does the fuel gauge get it's information from is it direct from the float in the tank or is an ecu also involved.

[Peter.N.]

Had a similar problem when I bought mine, gauge showed a little fuel and no light on, just got onto the motorway and ran out The car had an electrical fault when I bought it for which I had to disconnect the battery to resolve, when I reconnected it the gauge registered empty and the light was on - its been OK ever since, so try disconnecting the battery.

Peter

[acrowot]

Thanks Peter I have already tried this to no avail.
I would also like to clarify the 200 miles reading this is on the mileometer on the speedo and represents the actual mileage I have travelled since filling up and although initially the gauge was dropping to reflect the first 150 miles I had travelled on this tankfull the gauge now reads full without any further fuel being added.

[Peter.N.]

Ah, I can only suggest you carry a gallon of diesel with you.

Peter