Testing TPS anyone know how?

Discussion in 'EFI/carb' started by Tepco, Jul 20, 2012.

  1. Tepco Husqvarna
    AA Class

    Location:
    Greensboro, NC
    Husqvarna Motorcycle:
    2008 SM510R
    Other Motorcycles:
    NT650, XR100, CR85SM
    So I understand that you cant ADJUST the TPS with out the iBeat, but can you test it using an ohms meter to be sure you are getting contact throughout the entire movement of the throttle? My thought is that if it works like a car TPS you can have dead spot in it sending confusing signals to the ECU. This would cause the ECU to think you were opening/closing the throttle in turn adjusting the injector flow. Being that you have the throttle still open and air flowing in, the changing of the fuel flow would cause lean conditions. Any thoughts or ideas on how to TEST the TPS.

    2008 SMR510

    Thanks
  2. OlderHuskyRider Husqvarna
    Pro Class

    Location:
    Austin, TX
    Husqvarna Motorcycle:
    2010 TE 450 - last of the ITA motors
    Other Motorcycles:
    Kwaka KLE, HD FXDWG
    Symptoms of a Defective TPS
    • Bucking and jerking of the car.
    • Idle surging of the car.
    • Sudden stalling of the car engine.
    • Hesitation while the driver of the car is trying to accelerate.
    • Sudden surge in car's speed while driving on the highway.
    Testing TPS
    TPS are manufactured using switch, potentiometer and combination designs. If it is not adjustable then it becomes mandatory that you check throttle stop and throttle cable adjustments. Their improper functioning could cause symptoms such as, poor startup of the car, inefficient response of the throttle of the car, or idle stop. Switch and combination TPS are tested with ohmmeter. In order to test a non-adjustable TPS such as potentiometer TPS, a voltmeter is used and the following list, describes the steps involved in it.
    • You need to disconnect the throttle sensor harness.
    • Open the throttle valve manually and check the resistance between the terminal 1 and 2 changes.
    • Check the resistance in three different positions of the accelerator pedal.
    • You may record a resistance of approximately 10-ohms when the accelerator is fully, 2 to 10-ohms partially depressed and 2-ohms when completely released.
    http://www.buzzle.com/articles/symptoms-of-a-bad-throttle-position-sensor.html
  3. OlderHuskyRider Husqvarna
    Pro Class

    Location:
    Austin, TX
    Husqvarna Motorcycle:
    2010 TE 450 - last of the ITA motors
    Other Motorcycles:
    Kwaka KLE, HD FXDWG
  4. HUSKYnXJnWI Husqvarna
    AA Class

    Location:
    Central Wisconsin, USA
    Husqvarna Motorcycle:
    09TE450
    Checking TPS for proper function with an ohm meter may give some confidence- but checking with Ibeat (% and voltages) gives you the certainty you are looking for.
  5. Tepco Husqvarna
    AA Class

    Location:
    Greensboro, NC
    Husqvarna Motorcycle:
    2008 SM510R
    Other Motorcycles:
    NT650, XR100, CR85SM
    WOW, good read, my closed throttle reading is 1.030v and open is 4.30.
  6. BarberPole Husqvarna
    A Class

    Location:
    Above Boone, NC
    Husqvarna Motorcycle:
    2008 TE610
    Other Motorcycles:
    XT225
    There is a very interesting post that I read weeks ago, maybe over at TT, by a rider who relates the detriment of physically adjusting the throttle body butterfly position, with the Idle screw, BELOW this "closed" TPS reading attempting to lower idle RPM and thereby creating the dreaded leaness/flat spot response when opening the throttle for the first millimeter or so before "reaching" the "Closed" TPS position where the ECU starts receiving TPS input.
    I think a lot of earlier rider confusion around this possible situation caused many to go the PU route to remedy off idle flatness when proper setup by the dealer would have prevented it with a little Ibeat effort.

    EDIT: The Thread is actually here at the Cafe:

    "My DIY EFI Tweak" by bbcmat around Aug 6, 2009 in the EFI/carb forum

    Now we're hearing more and more recommendations to "reset" the TPS settings during mods.