Another TPS question!

[rich888]

To set the baseline TPS voltage at 157mV, you measure across the outer two pins of the TPS, engine stopped, ignition on, correct?

According to the wiring diagram I looked at, the outer pins, A and C (Violet and Violet/Black), are each end of the potentiometer and Yellow (B) is the wiper, which will indicate the throttle position.

I am slighty confused about how altering the position of the TPS, rotating it relative to the throttle can make the voltage across the ends of the potentiometer change?

Surely it would change the voltage on the wiper (yellow middle terminal)?

 

I have something wrong here but not sure what!

 

Is the TPS not actually a potentiometer at all? (the wiring diagram shows it as one)

 

 

[rich888]

OK, to answer my own question, there are two different wiring arrangements, for some reason.

I found another schematic with the wiper on the black/violet terminal C and +5v on the middle Yellow wire, which is how my V11 sport 2001 is wired! Phew. I tought I was going mad for a moment...

My TPS is reading 375mV with the throttle closed and cold start off!

 

[Meinolf]

Hi Rich,

the TPS is a potentiometer. The voltage is measured between signal ground and the wiper. You probably know that the throttle must be completetly closed when setting the baseline to 157mV - using a DMM, software measurement via GuzziDiag will not work.

Rotating the TPS changes the relative position of the wiper, hence the voltage changes.

Cheers
Meinolf 

[Lucky Phil]

11 hours ago, Meinolf said:

Hi Rich,

the TPS is a potentiometer. The voltage is measured between signal ground and the wiper. You probably know that the throttle must be completetly closed when setting the baseline to 157mV - using a DMM, software measurement via GuzziDiag will not work.

Rotating the TPS changes the relative position of the wiper, hence the voltage changes.

Cheers
Meinolf 

Hi Meinolf, is there any difference between the old large style TPS voltage profile and the later smaller version. I'd like to use the Centauro throttle bodies with the larger style TPS when I fit the engine to my 2000 V11 greeny which uses the 15RC ( I think?) ecu and smaller TPS.

Thanks

Ciao   

[Tinus89]

23 hours ago, rich888 said:

OK, to answer my own question, there are two different wiring arrangements, for some reason.

I found another schematic with the wiper on the black/violet terminal C and +5v on the middle Yellow wire, which is how my V11 sport 2001 is wired! Phew. I tought I was going mad for a moment...

My TPS is reading 375mV with the throttle closed and cold start off!

 

Don't forget you also need to close the butterfly valve completely, which means backing off the high idle mechanism and idle stop screw, as well as unlinking the connecting rod. Otherwise the butterfly valve is not closed, but in idle position. In that position it should be around 571mV.

[rich888]

2 hours ago, Tinus89 said:

Don't forget you also need to close the butterfly valve completely, which means backing off the high idle mechanism and idle stop screw, as well as unlinking the connecting rod. Otherwise the butterfly valve is not closed, but in idle position. In that position it should be around 571mV.

Got it sussed now!

I eventually found the difficult to get at throttle stop screw. It's reading 80mV now, fully closed.

Here is the TPS profile, showing the change in slope and the lack of any drop outs: