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Throttle Position Sensor how to?


R1100RSpurist

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R1100RSpurist

In an attempt to discover why my engine is acting up (check previous post of mine), I tried to check my TPS, the problem is, i dont exactly know how, or even if my harbor freight volt meter is up to par. can someone help?

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In an attempt to discover why my engine is acting up (check previous post of mine), I tried to check my TPS, the problem is, i dont exactly know how, or even if my harbor freight volt meter is up to par. can someone help?

 

 

Owen, attach the black lead of your DVM to the ground wire that’s attached to the L/H throttle body (make sure you have a perfect resistance free attachment),, then attach the red lead to the red/white wire entering the TPS connector (located on the L/H throttle body.. (pull the connector’s rubber boot down & use a paper clip to back probe the bottom of the TPS connector red/white wire, then attach the red lead of your DVM to that paper clip)

 

The TPS (throttle position sensor) is that black plastic looking module like thing on the L/H TBI unit (the one with a 4 pin connector on the bottom)..

 

Once the DVM red lead is hooked to the paper clip & the DVM black lead is firmly attached to the TBI ground wire,, then set the DVM to the 0-5 DC volt scale (or 0-10 DC volt scale, or something in that region,, must be DC volt setting).. Then, turn the ignition switch on,, make sure the engine cutoff switch is on , and also make sure the sidestand is UP (don’t start engine) ..

 

 

At this time your TPS voltage should be under 1 volt.. If not, verify all is set per above..

 

Then s-l-o-w-l-y operate the throttle to about ½ throttle & watch the voltmeter.. The voltage increase must follow the throttle & stroke smoothly from under 1 volt dc at closed throttle to about 5 volts as the throttle is slowly opened.. If you have any flat spots in the voltage, or dips, or even spikes verify you have good connections per above then re-test..

 

If the voltage still doesn’t stroke smoothly move the DVM black lead to the battery (-) post & re-test (if that changes the readings you have chassis grounding problem or ground side wire resistance) ..

 

When you are sure your TPS strokes smoothly & cleanly re-set your DVM to the milivolt scale then make sure the fast idle lever is OFF.. You should see around .340-.395 volts at closed throttle (on the idle stop screw)..

 

When done, remove the Mortonic fuse from the fuse box for about 30 seconds to re-set the Motronic computer..

 

One thing to keep in mind here that most small cheap DVM's don't update very fast so some won't follow the throttle precisly if you move it (the throttle) too fast..

 

Questions? –just ask ..

 

Twisty

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Owen, note Twisty said "DVM." A typical budget needle volt meter is not going to be accurate enough. If you don't have one, buy or borrow a digital volt meter for this adjustment.

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With a needle slid into the harness (Attaching the multimeter with aligator clips), I always set them up to .375 ohms. Guys screw around with them all the time. Something to do with better reception? dopeslap.gif

 

Some non technical folks start rumours about better performance/ better fuel economy by turning clockwise and counterclock wise its all BS. Make sure to disconnect your battery for 10 minutes and once reattached turn the key on (Dont start yet) and turn the throttle (Full Opperation) 2-3 times so the ECU can verify the numbers coming back from the readjusted TPS...

 

Good Luck

Tomas lurker.gif

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Ken and Twisty are correct. Borrow a digital Multimeter. Dont screw around with the TPS unless you have the right tool. Make sure you use some clear nailpolish to lock the outside of the screw again.

 

Tomas

 

Tomas

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With a needle slid into the harness (Attaching the multimeter with aligator clips), I always set them up to .375 ohms. Guys screw around with them all the time. Something to do with better reception? dopeslap.gif

 

Some non technical folks start rumours about better performance/ better fuel economy by turning clockwise and counterclock wise its all BS. Make sure to disconnect your battery for 10 minutes and once reattached turn the key on (Dont start yet) and turn the throttle (Full Opperation) 2-3 times so the ECU can verify the numbers coming back from the readjusted TPS...

 

Good Luck

Tomas lurker.gif

 

Tomas, did you mean .375 volts? Setting a TPS by ohms is not a good way to do it..

 

Also he has an 1100 that does not use a learn enable Motronic like the 1150 2.4 system so there is no need to turn the throttle 2-3 times so the ECU can verify the numbers coming back from the readjusted TPS.. The 1100 just uses the actual voltage it receives from the TPS.. I think you are thinking of the 1150 as that does have the learn enable Motronic..

 

Twisty

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You guys are correct in that an analog (old style dial/needle non digital ) volt meter would give a somewhat inaccurate real world TPS voltage reading due to the inherent low impedance in an analog type meter but for purposes of catching a momentary hole in the TPS output voltage might actually be a better choice as the reaction time of those analog type meters is very quick & those old dinosaurs don’t use digital averaging or electronic dampening (what you see is what you are getting) ..

Personally I still like my old analog meters for certain functions & as long the low impedance of the analog set up doesn’t really skew the circuit being worked on it can actually make finding some problems easier.. (finding the problem_yes,, making the final TPS working adjustment_no..

 

Twisty

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R1100RSpurist

Im not adjusting anything, i am just taking the bike in next week to BMW ($) and this is my last ditch effort to find out whats wrong, i got to thinking my TPS may be dead and grabbed onto that idea, but i will try with a good voltmeter soon.

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