Throttle position sensor

[johnl]

Sorry, I know its not a GS but very similar.

BMW R1100s single spark 1999. The bike is running rough. It has no go and 'holds back ' under acceleration. So far I have changed air filter, fuel filter, plugs, plug lead, coil, checked valve clearence, balabced throttle bodies, washed out out tank.

I swapped the throttle body complete with TPS from my good R1100s but no change.

The bike went into BMW today to try and diagnose the fault with the use of their computer. The computer says

' Throttle Valve potentiometer fault on upper or lower trail path '

This suggestd it is a fault with the TPS however as stated I have changed this before.

So, might it be the wiring to the TPS from the ECU? Does the wiring to the ECU just clip on / off as it does at the TPS end? is the wiring easily interchangable?

I shall have a more detailed inspection at the weekend.

Also, anyone any further thoughts or experiance of the TPS?

thanks
john

 

[Colban]

I doubt that the TPS section of wiring can be removed in isolation.
Have you tried reseating the main ECU connector and checking it for corroded pins (after disconnecting the battery +ve).
Also do the TPS reset procedure.
The TPS is only a variable resistor that changes an input voltage to the ECU so that the ECU knows where the butterfly is positioned.
May also be worth looking for trapped wires or a bad earth.