We had a 996 come in with a bad clutch & flywheel. After we replaced both assys with the correct OEM parts it would not start.
Among the multiple fault codes found was "reference sensor" code. We replaced the sensor & cleared the codes.
Veh started w a bit of effort & idled well, however it would not pull over 3,000 RPM. When the fault codes were checked, the "reference sensor" fault was present again and the motor stayed flat.
The sensor position is fixed, it cannot be adjusted or moved. We installed another new sensor, cleared the codes and the same fault came back.
After scratching our heads on this for a while, we pulled the flywheel and found the trigger ring out of round but no sign of damage or being bent. The original box also showed no sign of external damage.
Apparently the out of spec trigger ring caused the failure to rev over 3k.
Has anyone else experienced such a problem? Checking the pulse output would have verified the problem, but we cannot find what the voltage should be.
Len at Autosportengineering dot com