TPS question

[BennSport]

That makes sense. When I initially tested it I was getting no resistance readings. I’ll test it this weekend and see if I even get continuity at idle and WOT.

[cda951]

Some of the confusion would be alleviated with the correct terminology: the normally-aspirated 944 uses a 3-pin throttle SWITCH (not a position sensor). It contains two microswitches, one for idle and one for full load (~66% throttle opening). There is no potentiometer with variable resistance.

A TPS or throttle position SENSOR contains a variable resistor. The 6-pin 951 TPS is unique in that it contains both a microswitch that conveys idle position to the DME and a variable resistor, the signal of which is fed to the KLR. The KLR in turn transmits the full load signal to the DME to disable closed-loop feedback from the oxygen sensor.

Bosch DME systems of the early-mid 1990s and later use a 3-pin TPS with potentiometer only, no microswitches. Zero throttle position in the potentiometer flags the idle position, ~66% throttle position denotes full load, much simpler and more reliable. But does not work with factory Porsche 944/951 DME software. Perfect for aftermarket standalone engine management, though.