ElMartillo

Searched and the only one I could find described the connector to have four wires. Mine has three.

Thanks!

Saudade

From the '93 FSM (I think yours would be the same).

Throttle Position Sensor (TPS)
1) Turn ignition on. Check TPS output voltage at sensor wiring harness center terminal. At idle, output voltage should be greater than .2 volt.
2) Gradually open throttle plate. Output voltage should gradually increase as throttle plate is opened. At wide open throttle, output voltage must be less than 4.8 volts.

ElMartillo

This means at idle position, not with the engine actually running, correct?

Saudade

On but not running. I've seen other posts that backprobe all three. Sort of what you read for the 4 pin connector. Bear in mind the 4 pin connector only had 3 wires. On my Renix, I have a 4 pin and a 3pin so many of the posts you saw may be about this type.

lawsoncl

The testing is best done with an old school analog meter, but who still has one around these days? In addition to the idle and wot voltages, you want to see it changing smoothly as you open the throttle. Like a volume ****, scratchy, dead spots are bad.

With the connector plugged in and key-on, not running, you should see close to 5 volts on the supply pin and 0 on the ground pin. Also with the connector unplugged, measure the resistance from the ground pin to the chassis or battery. The resistance should be under 1 ohm. If not, you need to visit Cruiser54.com and follow his tips on refreshing all the ground connections. Actually hit his page anyway, as it's full of great info and cleaning up the grounds on a 30-year old vehicle is always a good idea.

ElMartillo

Thank you. I am fully familiar with 54’s tips. My symptoms are not such that I’m looking for flat spots. The engine runs and accelerates great. It’s bad at idle mostly, and yes the IAC is clean and functioning, as far as I can tell.

Symptoms: Hard starts in cold temps when engine is cold, to the point I need to floor the accelerator to get it to start. Even then rough running until it warms up, idle smoothes then comes down to normalish idle rpm. When engine is hot high idle upon startup, and intermittent high idle at stops.

ElMartillo

A very consistent 1.28 volts at idle position, 4.02 volts at wot position.
5.05 volts at supply.

Saudade

I still have my Micronta from Radio Shack when it was still Tandy Corp.

lawsoncl

The clam shell one? I've got one of those somewhere too.