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  • Adjusting the TPS (Throttle Position Switch &/or Sensor)

    1) TPS = This is two devices in one. Throttle Position Sensor.

    TVS: Throttle Valve Switch; On a manual car it is an Idle Switch, on an Auto it is both Idle and Full Throttle Switch.

    TPS: On both manual and auto the 2nd part of the device is the same "Throttle Position Sensor" or "Potentiometre".

    This Sensor is located on the side of the throttle chamber, a small rectangle black box.

    2) The devices wiring:

    TVS: This is the 3 pin plug on the front of the sensor. The top pin is the Idle Switch. The middle pin is the common pin. The bottom pin is the Full Throttle Switch.

    TPS: On the backside of the sensor comming out of the rear bottom corner are some wires with a larger plug about 10cm away. I will talk about this later.

    3) Initial setup of the TPS:

    Step 1) Take off the intake duct from the throttle chamber so that you may see the 'butterfly' or 'throttle plate'. First you must check that your throttle stopper is set correctly so that your butterfly isn't staying open (letting excess air through) and that it isn't closing too far (this will cause a 'sticky throttle').
    Some may be different but most will just need a small flat blade screw driver to adjust it. To locate the stopper simply look at the opposit side of the throttle chamber to which the sensor is attached, this is the throttle arm to which the throttle cable is attached. At the front/bottom you will see what the arm rests or 'stops' on. It is adjustable from underneath.
    BEFORE you adjust it have a look at the butterfly and where it sits, lightly turn the throttle arm to feel if it's 'sticky', if not then it is ok. Now get a thin sheet of paper and using the corner see if you can slide it under the bottom or through the top of the butterfly while closed. If not, then all is good. If you can the you will need to undo the stopper slightly *1/4 turn at a time* untill the paper will no longer fit under. Now repeat the check to make sure it's not sticking.
    There is a small hole just before the throttle plate at the bottom of the chamber. This should be visable when the plate is fully closed.

    Step 2) Get your multi metre, a philips head screw driver or small 8 or 6mm socket with a long extension and someone to help you... or you can use some multi metre wires with the really small bulldog clips on the ends.
    Set the multimetre to continuity, this setting will have a symbol that looks like an arrow with a line through it close the the head!

    Undo the bolts holding on the TPS enough so that it's not totally loose but you can still turn it freely enough to adjust it by 1mm!

    Step 3) Holding the + side of the multi metre onto the middle pin, and the - side onto the top pin, continuity should be there. If you have an audible metre it will beep, if not it will go from "-" to "0.00" or any number above that on the screen. If you have a different metre and not sure how to use it PM me!

    Step 4) Still holding the metre on those pins get someone to turn the throttle. When it is turned (butterfly open) the metre will read null continuity. i.e. "-"
    Close it again and should come back.

    Step 5) Throttle closed and Metre still on same pins. Move the TPS untill it reads null. Now slowly turn it back the other way untill the metre reads continuity again.
    Lock TPS into place and do a check by turning the throttle. This should be good enough for most people.

    However, i like to get out the 'feeler gauges' used for gapping spark plugs. With the multimetre still on the same pins, with throttle closed, it should be reading continuity. Place a 1mm worth of gauges under the throttle arm and the stopper. The metre should go null, if not it needs adjusting again so undo the screws again.
    Now go down to a 0.6mm gauge. Should read null.
    0.5 or 0.4mm should read continuity!

    Plug the sensor back in and go for a drive. If it's jerky then it's switching 'on' too early. I.e. before the throttle is far enough closed.
    If it's not dropping back down to idle then it's not switching 'on'. I.e. null continuity even when the butterfly is completely closed!

    Step 6) Still seems to have trouble. Read the CA16 Workshop Manual. Section EF&EC page 69. You need to check the harness for dammage! Or CA18 WorkShop Manual Supp. Section EF&EC page 40.

    Additional ways to check without the use of a multi metre is by using Diagnostics mode 4 on the CA18 ECU. But this is not as acurate. Still need to check this to see if the ECU is getting a signal from the TPS or not!


    Just something to note when doing ECU diag mode 3. "Error Codes" Code 23 is the above item. Code 43 (Not on CA16's) is this item.

    For info and diags on how to check this please see Workshop Manual Series 2 Supplement section EF&EC page 59.

    Find the other plug for the TPS. It will also have three pins. With the flat part of the plug to the bottom (on the tps side) and looking into the plug. Right Pin, Middle Pin and Left Pin.

    Using your multimetre on resitance testing "ohms" (ohms 10 should do). Place the + probe onto the middle pin and the - probe onto the right pin. Turn the throttle arm and the resistance should change increasingly and decreasingly.

    If it doesn't it's either stuffed or your doing something wrong.

    This is ONLY how to check the actual TPS. There may still be other issues, either with the wiring or the ECU. To check everything else it is better if you read the manuals as listed throughout this and the previous post on checking TPS!

    Hope it helps

    Regards,
    Devs.
    This article was originally published in forum thread: All N13 EXA "How To's" started by DEVILsEXA View original post