996 Gauge install - gas gauge off...

[jgaude]

Hello there 986Forum folks,

I've done the 996 gauge cluster swap.. all is working well, except my gas gauge. My 996 cluster is off about a 1/4 tank of gas.. It fills fine.. but goes down too slowly. Like I'll go 250 miles on a half tank of gas.... I'm wondering if my fuel gauge is bad. I looked up the part number of the cluster and it's a C2 one... Not a turbo.. Can't tell if it's a c4 though. I'm getting into the EEPROM and was wondering if anyone knows it there is a calibration number to tweak?

Thanks!
...Joe

[JFP in PA]

Originally Posted by jgaude

Hello there 986Forum folks,

I've done the 996 gauge cluster swap.. all is working well, except my gas gauge. My 996 cluster is off about a 1/4 tank of gas.. It fills fine.. but goes down too slowly. Like I'll go 250 miles on a half tank of gas.... I'm wondering if my fuel gauge is bad. I looked up the part number of the cluster and it's a C2 one... Not a turbo.. Can't tell if it's a c4 though. I'm getting into the EEPROM and was wondering if anyone knows it there is a calibration number to tweak?

Thanks!
...Joe

996's require fuel level calibration. The tank has to be drained dry, then filled to a fixed level, then the unit is calibrated using a PST II, PIWIS, or Durametric system.

1. Disconnect the battery and cover terminal or battery.
2. Remove cap over the fuel level sensor system.
3. Remove fuel level sensor. (attached to the fuel pump inside the tank).
4. Using a fuel extractor, completely drain the fuel tank through the fuel level sensor opening.
5. Make sure that the two recesses on the left and right−hand sides of the tank are emptied completely.
6. Reinstall the fuel level sensor and, with "ignition off", fill the tank with 28 liters of fuel.
7. Perform tank calibration with the Porsche System PIWIS Tester:
· Select vehicle type
· Select control modules
· Select instrument cluster
· Select menu item "Tank calibration"
· Confirm calibration
8. The fuel level sensor system has now been calibrated.

[Qmulus]

Verify that the cluster is coded for a C2, not C4. The 996 C4 requires a tank calibration because the saddle fuel used on those cars does not directly measure the last 1/4 of the tank, but rather uses fuel consumption to determine fuel level. You will never be able to get it calibrated correctly if the cluster is not configured for the right tank.

[jgaude]

Thank guys!
I'll bet it's coded for a C4.. I'll try and find someone with a PIWIS that won't take my wallet for having a look/see!

...Joe

[KevinH1990]

Some of the guys on the British site - Index of / are also working on the cluster. (I noticed that they are using some of my pictures.) You may want to ask if they have some insight into which part of the code controls the fuel gauge.
How to - Upgrade to a 996 Instrument Cluster - How To - www.BoXa.net