TPS Voltage

[1320NUT]

1990 454 SS can anybody, tell me, what the tps voltage is, at idle, on there truck? trying to get a sense of which way I need to go. The factory manual is wrong, in the voltage they printed, they say 1.2 volts??? Thanks In Advance

[ChevyTech]

0.5 to 1.25 volts throttle closed.

Below .2 volt will set a trouble code.

[1320NUT]

so, am I to assume, that anywhere between .5 to 1.2 is ok? there's not a specific voltage it needs to be at? Thanks

[ChevyTech]

Anywhere between .5 and 1.25 volts is ok.

The TBI systems on these trucks looks at the TPS voltage when you go to start the truck and will use that voltage as a reference for zero percent open throttle. This system has a non-adjustable TPS and this is why the ECM monitors TPS voltage at start-up. If you have to hold the gas pedal down, AT ALL, to start the truck, this can cause multiple problems.

A failed TPS can put the system in the clear flood mode can make it so the injectors will not spray fuel.

If the ECM does not see and voltage on the TPS that shows it is at idle, the ECM will not move the IAC.

If a bad TPS is giving a voltage in the middle of the range all the time, you should not expect it to set a trouble code. This system does not set TPS codes unless the voltage is below .2, or near 5 volts. If the voltage stays in a normal range, but is wrong, or does not move, the system will not set a code.