Converting fuel gauge from 911 to 964/993 style

[ischmitz]

Some have asked me how I did my conversion to 964/993 gauges. Most gauges were pretty straight forward. The fuel gauge was a little bit more involved as you can see in the diagrams for the 911 and the 964/993 sending units.

The 964/993 uses an electronic module mounted to the sending unit tube to generate the signal for the gauge. Fortunately, the variable resistors are the same. Furthermore, the sending unit in a 964/993 does not provide the switch for the Empty light any longer. This signal is now generated in the Central Informer or Onboard Computer depending on what came with the car.

In order to make the 911 sending unit work with the 964/993 gauge you need the little black box (control unit, part Number 964.641.081.00) and you have to modify the 911 sending unit according to diagram 2. It workes like a charm for more than a year now in my car.


Original configurations for fuel gauge in a 911 and 964/993




Modified 911 sending unit with 964/993 gauge

There might be other ways to do this conversion. I spoke to North Hollywood Speedometer and they suggested to modify the fuel gauge instead. You need to check with them.


Cheers,
Ingo