Think I might have a bad one. The old one reads 1.98 to 2.05. I grabbed one off the shelf at work and it only reads 1.05. So anyone one know what its should be at with the throttle all the way closed

Throttle closed it's allowed to read anywhere between 0.2V to 1.25V. Then at wide open it's supposed read 4.5V.

Edit to add: that's according to the service manual.

[This message has been edited by Bloozberry (edited 02-28-2011).]

I think there are thresholds...
For instance anything higher than 4.5 is WOT.
Your IAC may be holding the new one open. Measure the voltage with the motor not running...it should read probably .25-.5 volts I think (with the key in the on position of course).

[This message has been edited by lou_dias (edited 02-28-2011).]

quote Originally posted by lou_dias: Your IAC may be holding the new one open.

No, it doesn't work that way. The IAC does not open/close the throttle butterfly, which is what the TPS reads. Bloozberry (and the GM/Helm FSM) is correct.

FWIW, I believe the ECM "learns" the actual closed-throttle TPS voltage at power on, just prior to each engine start, as long as the voltage is in the expected range.

[This message has been edited by Marvin McInnis (edited 02-28-2011).]

I believe that TPS voltage, closed throttle, should be around .45 volts.

The idle/WOT voltage readings for my '84 duke are .82 / 4.25

The idle/WOT voltage readings for my '86 GT are .45 / 3.96