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Decent Tune-up


docc

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Well , I stand corrected . It is 0.540 V not 0.450 V . This is the target V to reach when adjusting the desired throttle angle . Sorry . 

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  • 1 month later...

Last time I did a tune up,(pre-guzzidiag) so a little rusty and haven't been on the forum much last couple years so a quick question.I got guzzidaig a couple years ago and and was able to get connection confirmed but hadn't gone any further,as the bike wasn't in need of a tune up at the time and busy with "life"...

My question is,to re-set the TPS do you still have to turn the unit(I remember how delicate it was to get right) or can that be done in diag,or does the software just read and display it(replacing the voltmeter) and you still get have to "dial" the TPS unit to get the baseline number?

Bike has been running well but always felt that when getting off throttle,that last few millimeters of throttle opening(rolling throttle off coming in to a turn) was like a cliff,once you hit it,the bike's power would abruptly shut off like a switch.I always assumed this was an incorrectly set TPS baseline....

Thoughts?

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Hey, mznyc! Good to see you around!

So, for certain, the TPS setting is a voltage function (not guzzidiag). As you say, guzzidiag will display the "degrees opening", but the TPS cannot be set with that function.

As always, make sure all of the factors that influence the throttle plate are entirely defeated before setting the 157 mV baseline. True how sensitive the rotation is, as well as how it changes when tightened down. Just fiddly, though. Fuss with it until it's right (it's worth it!)

With the abrupt fall-off at low throttle opening, it is worth checking the linearity of the resistance in milli-Ohms across the TPS. Slowly open and close the throttle while observing for any jumps or opens. These indicate a bad TPS.  The replacement PF3C I sourced from California Cycle Works is still running fine at just over a year and 5,000+ miles.

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Hi,

setting the TPS to it's proper start position (which is 157mV with all connections removed) can only be done with a physical adjustment and a voltmeter - not Guzzidiag or any other software. 

Cheers
Meinolf

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3 hours ago, docc said:

Hey, mznyc! Good to see you around!

So, for certain, the TPS setting is a voltage function (not guzzidiag). As you say, guzzidiag will display the "degrees opening", but the TPS cannot be set with that function.

As always, make sure all of the factors that influence the throttle plate are entirely defeated before setting the 157 mV baseline. True how sensitive the rotation is, as well as how it changes when tightened down. Just fiddly, though. Fuss with it until it's right (it's worth it!)

With the abrupt fall-off at low throttle opening, it is worth checking the linearity of the resistance in milli-Ohms across the TPS. Slowly open and close the throttle while observing for any jumps or opens. These indicate a bad TPS.  The replacement PF3C I sourced from California Cycle Works is still running fine at just over a year and 5,000+ miles.

Thanks Docc,glad to be back!... Been dealing with family issues,other bikes,work,major house renovation and subsequent sale, for the better part of 2 years,so distracted by that,but a wonky running ride last fall and attempt this year ,found a mouse hole in the air filter(hopefully no further damage...!)..has me going back down the Guzzi rabbit hole,have had a Mistral X-Over sitting on the shelf for several years and a PCIII(bought pre GDiag) but if I can get proficient with GDiag I will attempt to do a map load or even a write!

Where am I checking resistance on the TPS unit itself?

3 hours ago, Meinolf said:

Hi,

setting the TPS to it's proper start position (which is 157mV with all connections removed) can only be done with a physical adjustment and a voltmeter - not Guzzidiag or any other software. 

Cheers
Meinolf

Thank You Meinoff

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29 minutes ago, mznyc said:

Where am I checking resistance on the TPS unit itself?

Between the black/purple (positive) and the purple (negative) at the TPS connector. You can do this by "back probing" (sticking needles or pins in to the backs of the connectors) or obtain the Casper's Breakout Harness, which is certainly the more elegant solution.

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Simple to do . Connect between A / C ( outer )  terminals of the connector . You will be using a DVOM so it doesn't matter about polarity . 

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6 hours ago, gstallons said:

Simple to do . Connect between A / C ( outer )  terminals of the connector . You will be using a DVOM so it doesn't matter about polarity . 

OK,So just like the old method of reading the TPS postion? What reading would make me suspicions of the unit?

Thanks

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14 minutes ago, mznyc said:

OK,So just like the old method of reading the TPS postion? What reading would make me suspicions of the unit?

Thanks

Bad TPS is not easily seen by a reading or even watching the progression of millivolts through its range. Much more likely to discover a bad spot in the TPS using Ohms in a very low range and watching the values slowly opening and closing the TPS. If the value jumps, skips, hesitates or goes open, the TPS should be replaced.

The resistance value should change very smoothly all up and down the range from closed to open and back.

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Hi,

14 hours ago, mznyc said:

OK,So just like the old method of reading the TPS postion? What reading would make me suspicions of the unit?

connect Guzzidiag, select graphical display and watch if the curve is smooth when opening/closing the throttle. Beware that there's a change in the gradient at 30°, it get's flatter when opening, due to the characteristics of this TPS's curve formula.

Cheers
Meinolf

 

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28 minutes ago, Meinolf said:

Hi,

connect Guzzidiag, select graphical display and watch if the curve is smooth when opening/closing the throttle. Beware that there's a change in the gradient at 30°, it get's flatter when opening, due to the characteristics of this TPS's curve formula.

Cheers
Meinolf

 

Great thanks,I'll try to take a screen shot or video when I get to it next week,hopefully won't have to go to a GDiag thread to get it up and running...:rolleyes:

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On 6/17/2020 at 9:04 AM, docc said:

 The replacement PF3C I sourced from California Cycle Works is still running fine at just over a year and 5,000+ miles.

The CA site specifically say not for any other MG models...

Screen Shot 2020-06-17 at 8.23.30 PM.png

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4 hours ago, Meinolf said:

Hi,

connect Guzzidiag, select graphical display and watch if the curve is smooth when opening/closing the throttle. Beware that there's a change in the gradient at 30°, it get's flatter when opening, due to the characteristics of this TPS's curve formula.

Cheers
Meinolf

 

So , this TPS is non-linear ?  

What is the reason / purpose of this ?

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18 hours ago, mznyc said:

OK,So just like the old method of reading the TPS postion? What reading would make me suspicions of the unit?

Thanks

It is only to verify the TPS is perfect . An easy test to perform and you KNOW it is good and if you have problems you know to look elsewhere . 

All of these tests you are doing , you want to be familiar with to the point you will be able to do this w/o having to "think" .

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