The TPS adjustment thread

[Aldotronic]

5 minutes ago, sirthumpalot said:

Did the problem just start suddenly, or has the bike always been this way?  If it started suddenly then you've likely got something wrong that needs to be fixed, maybe a leaky injector, etc..  

If the bike has always been this way, then you can try adjusting the TPS to lower the voltage a little bit and see if that helps.  Turn it down by 0.02 and test, keep going down if it keeps getting better.  Write down your original readings so you can go back if you want to.  

I found the service manual for the 2014 KX250F (click here), I don't know if that setting (0.60V at idle) is the same for your year or not.  Maybe check over in the Kawasaki forum and maybe someone there has the manual for your year and is willing to share the relevant pages.  It looks like Kawasaki likes to call it the "Throttle Sensor", so maybe search on that string.  I hope this helps, let us know what you find! 

It’s been like that since I got her and suspect it was a contributing factor for the previous owner to sell it.

I’ll certainly check the current TPS voltage.(did this on my older KTM but unsure about this model)

Need to check valve clearances too.

thanks your help and advice - will let you know if there’s an outcome - it’ll be a while before I get time to check it all.

[Burnrider]

2023 KTM XC 300

Matt, 

The TPS tool I bought for the '17 500 EXC fits the new TBI 2T. Can I use it to adjust the voltages per spec in the repair manual the same as the 500 EXCF? Not sure if they are using a computer access to verify settings that the average rider doesn't have in the garage. Clip from my manual note the bold faced words looking like they reference a computer page.

 

[sirthumpalot]

5 hours ago, Burnrider said:

2023 KTM XC 300

Matt, 

The TPS tool I bought for the '17 500 EXC fits the new TBI 2T. Can I use it to adjust the voltages per spec in the repair manual the same as the 500 EXCF? Not sure if they are using a computer access to verify settings that the average rider doesn't have in the garage. Clip from my manual note the bold faced words looking like they reference a computer page.

 

Disclaimer: I'm not yet familiar with the new TBI bikes.  That said; going by that snippet from the manual, it sounds like setting the TPS to factory specs is a 2-step deal.  First physically adjust the TPS to 0.40V, second follow their little procedure there to teach the ECU the current setting.  It does sound like those bold words refer to screens on the KTM dealer tool.  All of that said, it does sound to me like you can use the TPS Tool to make your adjustment; and likely by skipping the "teaching" step you can tweak the TPS to fine tune the fueling just like on the EXC.  It also sounds like you might be able to do the whole thing without the KTM tool.  Are you able to post that whole section from the manual, or better yet upload it to manualslib.com?  Then we can read the whole thing and figure out if I'm right.   

[Spud786]

14 minutes ago, sirthumpalot said:

Disclaimer: I'm not yet familiar with the new TBI bikes.  That said; going by that snippet from the manual, it sounds like setting the TPS to factory specs is a 2-step deal.  First physically adjust the TPS to 0.40V, second follow their little procedure there to teach the ECU the current setting.  It does sound like those bold words refer to screens on the KTM dealer tool.  All of that said, it does sound to me like you can use the TPS Tool to make your adjustment; and likely by skipping the "teaching" step you can tweak the TPS to fine tune the fueling just like on the EXC.  It also sounds like you might be able to do the whole thing without the KTM tool.  Are you able to post that whole section from the manual, or better yet upload it to manualslib.com?  Then we can read the whole thing and figure out if I'm right.   

Sound to me like the 3 swipes of throttle calibrates the tool, rather than the bike.

[sirthumpalot]

27 minutes ago, Spud786 said:

Sound to me like the 3 swipes of throttle calibrates the tool, rather than the bike.

That wouldn't make technical sense. Without seeing the rest of the manual, my best guess is that stores the values in the ECU and the tool then reads it from the ECU and displays it. 

[Burnrider]

The dealer gave me a dongle 6 pin connector with 2 pins used as a jumper. He said it was only used to reset the computer defaults on the servo motor when rebuilding the topend.

It turns out that jumper goes into a connector accessing the ECU.

Truemoto North also uses it for an ECU power source to their their headlight kit. I plugged it in and it powered the ECU as the map switch lit up.

Checking the red idle position, it was at .58 same as my 500. I unscrewed the red knob all the way out for a .39 rating- close enough to .40 to call it good. RM refers to specific butterfly positions of 3 and 5 degrees  for the cold start (yellow button) for setting, but no way to do that with the TB on the bike. 

I'll send the manual sections to you -pm as it is a purchased KTM manual and not a public access document . Great bike, but it's a new riding skill after not having rode 2T for 25+ yrs. A ton of low end power, no more 4T clutching in the woods, better to modulate the throttle. The servo motor picks it up from the bottom anywhere and powers up, it's there for your demands. Handling is something you would have to ride to believe, same or better than the '22 depending on skill level.

Edited November 16, 2022 by Burnrider

[Burnrider]

Matt, got an email or dropbox address for a word document I can send you?

[Spud786]

9 hours ago, sirthumpalot said:

That wouldn't make technical sense. Without seeing the rest of the manual, my best guess is that stores the values in the ECU and the tool then reads it from the ECU and displays it. 

I doubt the manual will tell you much more.

 

 

 

[sirthumpalot]

10 hours ago, Burnrider said:

Matt, got an email or dropbox address for a word document I can send you?

I'll PM you an email address. ? 

[MX28]

On 11/16/2022 at 7:43 AM, sirthumpalot said:

I'll PM you an email address. ? 

Just want to confirm before ordering that this is a viable way to adjust and tune my 2022 MC350.

Also, what is the ideal set point? I don't quite understand the idea of tuning this "until it feels good". 

Edited January 17, 2023 by MX28

[sirthumpalot]

3 hours ago, MX28 said:

Just want to confirm before ordering that this is a viable way to adjust and tune my 2022 MC350.

Also, what is the ideal set point? I don't quite understand the idea of tuning this "until it feels good". 

In all honesty, I don't have any feedback from anyone with an MC350 yet, so I'm very curious to hear your results.  As long as they used an adjustable TPS on it then adjustments are possible.  It's adjustable if the TPS has slots for the mounting screws.  So far the only bikes with non-adjustable TPS I've seen are the TPI 2-strokes, so I would bet $1 it's adjustable. 

Regarding the "until it feels good "part; think back to the carburetor adjustment days, when you would adjust the fuel screw (on a 4-stroke) or air screw (on a 2-stroke).  You would go in a little, out a little looking for the best spot.  This is the same idea, you turn the TPS in one direction (up or down) to see if you like it better.  Keep going up if it's better.  If it's worse then just go the other way.  Adjustments of 0.02V should be noticeable on most motors.  It will have the most effect at about 1/3 throttle and below.  

There's no risk with the tool, if you're not happy then return it for a refund. ?  

Edited January 18, 2023 by sirthumpalot

[Spud786]

31 minutes ago, sirthumpalot said:

In all honesty, I don't have any feedback from anyone with an MC350 yet, so I'm very curious to hear your results.  As long as they used an adjustable TPS on it then adjustments are possible.  It's adjustable if the TPS has slots for the mounting screws.  So far the only bikes with non-adjustable TPS I've seen are the TPI 2-strokes, so I would bet $1 it's adjustable. 

Regarding the "until it feels good "part; think back to the carburetor adjustment days, when you would adjust the fuel screw (on a 4-stroke) or air screw (on a 2-stroke).  You would go in a little, out a little looking for the best spot.  This is the same idea, you turn the TPS in one direction (up or down) to see if you like it better.  Keep going up if it's better.  If it's worse then just go the other way.  Adjustments of 0.02V should be noticeable on most motors.  It will have the most effect at about 1/3 throttle and below.  

There's no risk with the tool, if you're not happy then return it for a refund. ?  

And those that want to attempt to adjust with out a meter, all you have to do is loosen the screws, and the reading can change so bad, you may never get it back. The TPS tool wire Harness, Ive had mine for years, wouldnt be Caught without it. Anytime you need to check tps, for me its a needed tool.

[MX28]

12 hours ago, sirthumpalot said:

In all honesty, I don't have any feedback from anyone with an MC350 yet, so I'm very curious to hear your results.  As long as they used an adjustable TPS on it then adjustments are possible.  It's adjustable if the TPS has slots for the mounting screws.  So far the only bikes with non-adjustable TPS I've seen are the TPI 2-strokes, so I would bet $1 it's adjustable. 

Regarding the "until it feels good "part; think back to the carburetor adjustment days, when you would adjust the fuel screw (on a 4-stroke) or air screw (on a 2-stroke).  You would go in a little, out a little looking for the best spot.  This is the same idea, you turn the TPS in one direction (up or down) to see if you like it better.  Keep going up if it's better.  If it's worse then just go the other way.  Adjustments of 0.02V should be noticeable on most motors.  It will have the most effect at about 1/3 throttle and below.  

There's no risk with the tool, if you're not happy then return it for a refund. ?  

Would you say it's a logical approach to make some adjustments, fire the bike up, and see how it responds to chopping the throttle? Is this an appropriate use of the tool? I can kill my bike on demand if I open the throttle too quickly.. lol cool right?  

[sirthumpalot]

19 minutes ago, MX28 said:

Would you say it's a logical approach to make some adjustments, fire the bike up, and see how it responds to chopping the throttle? Is this an appropriate use of the tool? I can kill my bike on demand if I open the throttle too quickly.. lol cool right?  

Adjusting the TPS could potentially help with this for sure, but it's one piece to the puzzle.  When the motor dies from opening the throttle too quickly, most likely it's lean (or the idle speed is lower than spec).  The same thing could happen if it's super rich, but with a stock ECU most likely it's lean.  Turning up the TPS voltage would give you a little more fuel and could help resolve the issue if it's just a little lean.  If it's a lot lean then altering the fuel map in the ECU, or altering the accelerator pump feature in the ECU (or adding a piggy back tuner) would be the more drastic steps.  So in short; adjusting the TPS could potentially solve it, especially if the TPS was just off from the factory, but since no one here has tried it on that model bike yet, we don't know if adjusting the TPS is enough or if you would need to alter the fuel map and/or accelerator pump feature in the ECU to solve it on that particular bike.  It's fun being the first guy isn't it.  ?  

Edited January 18, 2023 by sirthumpalot

[lamgar]

is there a reason you cant set the TPS with a ohm value rather than voltage?

[Ud_Luz]

52 minutes ago, lamgar said:

is there a reason you cant set the TPS with a ohm value rather than voltage?

None at all except the service manuals usually specify voltage. You can use the manual's baseline voltage as a reference for adjustment. 

[sirthumpalot]

49 minutes ago, lamgar said:

is there a reason you cant set the TPS with a ohm value rather than voltage? It's

It's less precise, unless you take a pile of readings and do some math.  For a carburetor where precision isn't an issue it's ok, but for efi it needs to be precise.  Watch these two videos and you'll get the idea, especially the second one.  I show the math at the end.  The material that provides the resistance isn't perfect and will vary between TPS units so you would need to measure and do math to figure out what setting you would need, but at the end of the day it's the voltage that the ECU reads so if the voltage is right that's all that matters.

https://youtu.be/F2ZwLt9h4ss

 

 

 

 

 

[lamgar]

OK makes sense I'm just in a bind where I don't have the tool and replaced the TPS on a 2016 husky 501. I have the tool for a 2019 ktm 450 exc but different clip. 

I wanted to run the bike this weekend. 

[lamgar]

also it has a vortex ECU so wasn't sure if it mattered if the TPS was set or not with this ECU or if you just had to do the relearn on the vortex ECU by cranking for 3 seconds with kill button on at 0% throttle and again at 100%. 

[sirthumpalot]

If your vortex is one with the learn function, then nothing to lose by taking a guess on the TPS then run the learn procedure and see what happens.