TB TPS Problems HELP!

[Bz Kn33z]

As heading says, i have problems with the TPS on my VN V6
I have a V8 TB on it and it plays up sounds like its missing tried replacing TPS same thing happens i checked the engine light code and it throw me number 22, which is TPS i then pulled the plug out on the TPS and tested the yellow/black wire like it said and i tested it with Multi-meter and it was around 6-7 volts then drop up and down maybe bad earth on "MM".
so yeah i dont really know what to do i can put my normal V6 TB on and its fine but i put the V8 on and its F**K*D.

Please help!Thanx

[Not_An_Abba_Fan]

Did you adjust the TPS to suit the V8 TB? What did you have your multimeter set to? It should be reading less than 1 volt. To adjust it, loosen the screws that hold it on just enough where you can move it without it springing back. Put your multimeter in the back of the plug while it is connected and turn the ignition on but don't start it. Move the TPS until the volts read between 0.66-0.76 V DC. Ideally it should read in the middle (0.71). Tighten up the TPS and it should be good.

[Bz Kn33z]

what should i have the Multi meter set to.

[Not_An_Abba_Fan]

Set it to 20 DCV. And test the voltage on the TPS plug with it still connected.

[Bz Kn33z]

it reads 42.5 and i move it side to side and it doesnt change i unpluged the IAC and it dropped to 24.0

[Bz Kn33z]

and that is puting the Multi meter into the back on the yello/black wire.

[Not_An_Abba_Fan]

How many wires has it got?

[Bz Kn33z]

3 wires. 1 yellow/black, 1blue, 1white.

[Not_An_Abba_Fan]

Try the blue with the positive probe and the white with the negative probe.

[Bz Kn33z]

Done that and it read 4.11

[Not_An_Abba_Fan]

hmmmm. That says that it is at WOT, it should be down around 0.7. Does it change if you move the throttle or the TPS?

[Bz Kn33z]

When i have the blue wire and white wire on the Multi meter it just reads 4.11 and it stays there even when i move the trottle.

[Bz Kn33z]

so so lost dont no what to do looks like its back to the V6 TB

[Bz Kn33z]

Put the V6 one back on and it is reading off the blue and white wire 41.0 so yeah i'm lost

[Cheap6]

The TPS is just a variable resistor, similar to that you would buy in an electronics store but in a different package.

What you should have with the three wires is:

A reference voltage from the ECM, nominally 5.0V but high 4. something is OK.

An earth.

The TPS signal, back to the ECM - somewhere between 0V and the nominal reference voltage, depending on the position of the sensor.

To check what signal (voltage) is being output by the sensor, with the connector plugged in and ignition on, check each wire in turn between the terminal for that wire and any of:

a point on the car's body.

the negative battery terminal.

the engine.

(ie. an earth).

(Pull the insulating boot on the wiring harness back and carefully insert a dressmakers pin into the back of each terminal you want to test, in turn, and touch the voltmeter probe to the pin) You should get one of the voltages (or none for the earth) for each wire. That will ID the wires and give you what the ECM is seeing. Moving the throttle will confirm the signal voltage as it should change with throttle position.

Not_an_Abba_Fan is correct in saying the signal voltage should be low with the throttle closed. 0.7V would be about right but it could be a bit below that. So long as it is between 0.2 and 2.5V when the engine is started it won't set a code and the ECM relearns the closed throttle TPS position as whatever it is when the car first starts (so don't start the car with your foot on the accelerator ). If it is on the high end of that range, the ECM may not enter open loop operation correctly under some load conditions.

A code 22 is TPS voltage too low, so the TPS is reading as if the throttle is too far closed. Neither V6 or V8 TPS (they are the same sensor) have any provision for adjustment so if the reading for the V8 one is out of range you may have to slot the holes in the TPS to allow adjustment.

[Cheap6]

This may help too:

vn,vp ecu pinout

(Spanners' PDF).

In GM speak, "L" is blue, the signal wire. The grey (a dirty white?) wire is the reference voltage and the black with yellow trace is the earth to the ECM.

4.11V between the blue and "white" (grey) wires is actually OK but it should vary when you move the throttle. (It is the voltage drop across the TPS).

(5V - 4.11V = 0.89V, a bit high but acceptable).

[Not_An_Abba_Fan]

Check the voltage between the signal wire and the earth. Thats the one that should vary with moving the throttle. Fully closed should be around 0.7v and fully open should be around 4v. I thought the white was the earth. Never looked at a VN.

[Cheap6]

Check the voltage between the signal wire and the earth. Thats the one that should vary with moving the throttle. Fully closed should be around 0.7v and fully open should be around 4v. I thought the white was the earth. Never looked at a VN.

Yeah, I normally work it out on the car from what the voltages are, rather than try to remember the wire colours. They can be different from model to model.

I remembered something else last night too, VP V6 (at least) have a "drive adaptor" between the throttle body spindle and the TPS. It is easy to misplace (lose) the adaptor if the TPS is removed/swapped. If it is missing the TPS won't move with the throttle spindle = code 22. Worth checking I think, esp. w' a TB of unknown history. It should be obvious by looking at the drive slot in the TPS and the TB spindle whether there should be an adaptor present. They used to be available separately: VS20091 (yes, I had to look it up!) for the V6, possibly the same # for V8.