multimeter question and tps sensor

are you hooking the + to the green ?
and don't hook the - to the black wire, go black directly to ground, it will make a diff on the setting.

nitrous_bob said:

are you hooking the + to the green ?
and don't hook the - to the black wire, go black directly to ground, it will make a diff on the setting.

Click to expand...

Wrong answer.

The black/white wire is the signal ground: use it whenever you make voltage checks on any of the sensors (TPS, EGR, MAF, ACT, ECT). The computer references all the sensor input to this ground and not battery ground. The difference is usually only a .05-.1 difference, but that is important to the computer.

Try this... Currently there is some dispute about setting it at .99 volts being worth the effort, but anything less is probably OK. All you need is less than 1.0 volt at idle and more than 4.25 at Wide Open Throttle (WOT). Somewhere between .70 and .99 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.

JR, as always, is right-on.
You want to 'see' what the computer is seeing. And if the computer's sensor ground is tainted, you want to see that in your testing.

Ohming out the supplied TPS ground is never a bad idea if one has reason to question it.