Looking for help with a fuel gauge issue in my 2012 Cayman R set up as a GTB1 race car.
Like many builds, wiring was changed considerably during the rebuild process (not done by me or current shop), so whenever master switch is off the power to the fuel gauge is also lost resulting in a loss of calibration. If the master is bypassed, the gauge results in a drain on battery. Anyone encountered this issue before? Any thoughts on solutions?

 

Common issue. Only fuel with the power on.

BTW - if you have significant power drain with the master switch on, you have other issues that should be corrected. Other than your data acquisition system, there should be no power drain and you can put data and cameras on a switch.

 

Thanks for the response.
Unfortunately, it loses calibration as soon as the power is completely off, so fueling with the power on doesn't help.

 

Not sure I understand. You switch the main power off and then on again. You start the car and the fuel lever says empty? If so, how long does it take for the fuel lever to adjust to the correct fuel level as you drive the car? Or does it always stay at zero?

What do you mean by "loss of calibration"?

 

We calibrate the gauge with the power on using the Porsche calibration tool. Gauge works fine but then when we turn the power (master switch) off and back on again the gauge reads empty. Power is restored to the gauge when the master is turned on but it stays at empty while driving and no matter what is done to the fuel level, hence the thought that it is working just not maintaining calibration? I've been told that in a car from the factory there is a permanent low voltage connection to the battery with some kind of resistor so calibration can be maintained. Does any of this make sense?!?

 

I am not sure about the low voltage to fuel sender connection. Here is my experience from a 987.1, 987.2 and 997.2: Always fuel with the power on or otherwise the gauge will read zero when you turn the power back on. Turning off the power on the 997.2 for extended periods of time sometimes causes the fuel gauge to read zero. It can be woken up by fueling the car with the power on. Sometimes the wakeup takes 5-10 min.

 

Thanks again. Will give this strategy a try next time I'm at the track.

 

Keep us posted!