Does the Throttle Position Sensor Need to Work to Turn on the ICV?

[66Vette]

I was doing some testing on my car and checked the operation of the throttle position sensor by looking at pin 52 of the DME harness and ground. With the throttle closed, my understanding is there should be zero ohms. Mine was open, but if I put a little pressure on the throttle towards the closed position, I see zero ohms. Doing this I can also hear an audible click when the pressure is applied. When I turn the key to the on position, the idle control valve buzzed (without continuity of 52 to ground). Does the DME need to see the throttle position sensor with continuity to turn on?

The car runs fine except does have rare spells where it either dies suddenly (and starts right back up) or will not start easily. It never has left me stranded.

[nando]

yes, if the switch isn't closed it won't go into idle mode (it only senses closed, open, and full throttle). it might also be mis-adjusted. you could test the switch with a multimeter to see if the closed/full throttle switches are working and adjust as needed.

[66Vette]

Thanks Nando. I'm digging a little further into the issue just to get a good understanding. The ICV looks like it will buzz whether or not the throttle position switch is in the grounded (idle)position. I am guessing that the ICV changes operation when the throttle position switch goes to the idle position.

I also checked the voltages on the connector to the throttle position switch. The Bentley manual says it should be AT LEAST 5V, mine reads 11V on both the WOT and Idle pins. Anyone ever measure that voltage? I would be curious if 11V is typical. I measured with the TPS cable disconnected, ignition on, and placed a voltmeter between the center pin and either of the two outside pins.