I was having a play today with the OBD2 reader and noticed something odd - the throttle position sensor was reading 17.5% open at idle, fair enough, but at full throttle it never read higher than 94.5%.
There is no problem mechanically the throttle pedal opens the butterfly just as far as working it by hand.
So the question is - is this typical?
Am I missing out on 5.5% of power?
Is the position sensor adjustable or fixed?
The engine is a 1.7 l Ford Sigma with the standard throttle body.

Thanks for any comments.

The actual angular range of the throttle pot always has to be bigger than the movement of the throttle otherwise you would physically break it every time you used the car.

Throttle pot calibration usually tells the ECU that the lowest figure should equal 0 and the highest 100%
The problem here is whether the OBD is showing TPS actual reading or ECU interpretation

Actually .........................

Quote from the Ian Hawkins Torque App web site http://torque-bhp.com/wiki/Throttle_Position


"Throttle Position "

"This is the reading from the potentiometer at the manifold - it is not a reading from the accelerator pedal."

"You may see that this reading never reaches 0%, and in some cases does not also reach 100%. There are a few reasons for this:"

" The reading is relative. 13% on the potentiometer may be fully 'closed' in terms of throttle."
"On some vehicles this also represents the idle state (on these vehicles 0% would mean fully closed throttle - no air=engine stall). "

" For readings that do not reach 100%, this may also be due to the relative reading of the potentiometer."
" The ECU map may also contribute to this as on some vehicles the throttle (controlled by the ECU) will close slightly at higher RPM - the VW Fox is one such vehicle that does this over 3000RPM. "





[Edited on 21/9/13 by britishtrident]

Thanks guys.

There obviously is no problem and I've learnt something.