TPS Voltage Readings

at tech school we always went to a ground on the vehicle.

The correct way is on the TPS wires, not on the body of the car. Do it that way. Dont believe me ask Jrichker lol

All you need is less than 1.19 volt at idle and more than 4.25 at Wide Open Throttle (WOT). Somewhere between .50 and 1.1 is the best range. You'll need a Digital Voltmeter (DVM) to do the job.

The Orange/White wire is the VREF 5 volts from the computer. You use the Dark Green/Lt green wire (TPS signal) and the Black/White wire (TPS ground) to set the TPS. Use a pair of safety pins to probe the TPS connector from the rear of the connector. You may find it a little difficult to make a good connection, but keep trying. Put the safety pins in the Dark Green/Lt green wire and Black/White wire. Make sure the ignition switch is in the Run position but the engine isn't running.

Here’s a TPS tip I got from NoGo50

When you installed the sensor make sure you place it on the peg right and then tighten it down properly. Loosen the back screw a tiny bit so the sensor can pivot and loosen the front screw enough so you can move it just a little in very small increments. I wouldn’t try to adjust it using marks.

(copied from MustangMax, Glendale AZ)

1. Always adjust the TPS and Idle with the engine at operating temp. Dive it around for a bit if you can and get it nice and warm.

2. When you probe the leads of the TPS, do not use an engine ground, put the ground probe into the lead of the TPS. You should be connecting both meter probes to the TPS and not one to the TPS and the other to ground.

3. Always reset the computer whenever you adjust the TPS or clean/change any sensors. I just pull the battery lead for 10 minutes.

4. Check the procedure for your year, on my 90 I have to turn the idle screw until it just touches the tab, then insert a .010 feeler gauge and give it about one more turn.

Engine off, key on. If there are no codes set adjusting the TPS doesn't do anything. The TPS zeros out automatically everytime you start the engine.

See http://forums.stangnet.com/showthread.php?t=534062&page=10 and the comments by joel5.0 on the inner workings of the computer and how it uses the TPS. Very interesting stuff.