Hesitation during hard aceleration

[windwheeler]

Glad to hear donjack! 

Did you change the TPS position/voltage too? Otherwise just moving the MAP sensor I believe a TPS reset is not necessary.

[donjack]

No, I never touched the tps or anything else. I do believe that the tps reset procedure worked tho' I have now got into the (bad??) habit of doing a reset after I do anything on her, change plug, battery etc, after all it only takes a few seconds!!
Cheers,
Don.

[windwheeler]

Sure, does never hurt to clear "a bad memory" . 

For those here on the thread what you do to reset TPS memory:

• open throttle full
• turn on ignition  and wait 8 seconds
• close throttle
• turn off ignition

[Mysterio]

i have the same problem
and i would like to ask some questions
what is the TPS ?
where is the map sensor ?
what and where is the richer ?

actually i have had vibrations while take off but changed the clutch for one with better material and wider space and its gone
but still the hesitation while hard or full acceleration

[windwheeler]

I recommend you search for the on-line PDF Service manual, actually search MAP and TPS sensor adjustment or similar, and it showed up for me.  There it is with pictures.

The MAP sensor is where you start and it sits on the very top of the Intake, as I said with a metal locking tab.  The only thing you really can do is to move it in increments and see how the bike performs on the very same stretch of road.  It is trial and error. Probably several comparison tests are necessary until you see which position is best.  Make notes.

You do not need to re-install the whole luggage compartment bucket for test drives, just put the seat back in place and it will lock in, and it does not even need the nuts to be put on. On-off is quick like that.

IF you really want to move the TPS (a Torx T25 key is required to loosen the screw)
Richer setting is moving the TPS counter-clockwise in VERY small increments.  DO NOT go clockwise past the point where it came set from the factory (it will throw an engine error code that can be time consuming to remove); you need to make sure you make a reference mark where it is factory set to be able go back to that if necessary.  DO NOT disconnect the plug of the TPS. Reset the computer for the TPS every time after an adjustment as described in my former post.

[Ronnie]

I have a  2013 DT with the same hesitation, easy fix is on the throttle body is the map sensor loosen screw and turn it 180 degrees left
lock it in place tighten screw be careful not to loose O ring.

[windwheeler]

I have a  2013 DT with the same hesitation, easy fix is on the throttle body is the map sensor loosen screw and turn it 180 degrees left
lock it in place tighten screw be careful not to loose O ring.

You were just plain lucky if you changed it 180 degrees counter-clockwise and it worked. When I went to 180 degrees mine stalled constantly and didn't start properly after it had warmed up.

Usually there is a sweet spot that one needs to find by moving the MAP sensor in either direction in small increments. Then test ride the scooter and see it it got better or worse, and find the best position. It's usually trial and error until one gets the best result.

[BettinANDlosing]

Are you sure what your turning is the map sensor? And bit the tps? The map (manifold air pressure) has nothing to do with how it's oriented. The tps (throttle position sensor) does however. I don't see how or why the map would be adjustable or why that adjustment would change anything.

[windwheeler]

I can't tell you exactly what it does, but it does clearly change "something".  (PS: I am very familiar with the TPS, have adjusted that too, and yes, it also has an influence on the behavior under acceleration).)

What I saw is that there are holes under the MAP plastic cap that are when turned then aligned in a different position. I assume they change the vacuum and with that the voltage to control the computer, and with that the FI. It sure made a positive difference, but not with just one adjustment.

That's my theory based on observation...

[BettinANDlosing]

That's the only thing I could think too, maybe when it's turned it covers or uncovers holes in it.. Idk i wish Kymco used a megasquirt style system that could be tuned with the right tool.

[Ronnie]

You were just plain lucky if you changed it 180 degrees counter-clockwise and it worked. When I went to 180 degrees mine stalled constantly and didn't start properly after it had warmed up.

Usually there is a sweet spot that one needs to find by moving the MAP sensor in either direction in small increments. Then test ride the scooter and see it it got better or worse, and find the best position. It's usually trial and error until one gets the best result.

My DT has stalled after a warm start I just give it a little throttle when starting and its OK and doesn't stall during operation.

[zombie]

All of these scoots have their little quircks. You have to keep in mind, their not Ferrari's.

[CROSSBOLT]

Like Zombie said, Windwheeler, you the MAN! Genius is a great idea, experimentation either proves or disproves it. I do not experience any hesitation in my DT300i so probably will not try it subscribing to, "if it ain't broke, don't fix it" philosophy. Still, a nice "tool" that is not in the service manual.

Karl

[windwheeler]

Like Zombie said, Windwheeler, you the MAN! Genius is a great idea, experimentation either proves or disproves it. I do not experience any hesitation in my DT300i so probably will not try it subscribing to, "if it ain't broke, don't fix it" philosophy. Still, a nice "tool" that is not in the service manual.
Karl

Karl, what model year is yours?  I think KYMCO did change something in the computer from 2013/2014 model years on.  Yes, if you don't experience it, don't touch it   ;-)

[nushipwright]

Is it safe to do TPS/ISC reset if only in doubt? When not "necessary" so to speak?

For those not having the manual, excerpt from service manual:

TPS/ISC RESET

• If close or open the throttle grip randomly, the  ECU  may  record  the  incorrect  TPS when  the  ECU  or  the  throttle  body  has been reinstalled. It can cause hard to start engine or idling speed is not smooth when engine installation.
• ISC  has  a  motor  inside,  which  controls ISC  valve  to  obtain  smooth  idling  speed. The  ECU  may  record  the  incorrect  ISC position  during  the  engine  speed  isn’t working  when  the  ECU  or  the  throttle body  has  been  reinstalled.  It  can  cause engine stop, hard to start engine or rough idling speed.

The  throttle  position  sensor  (TPS)  and  idle air bypass valve (ISC) have to be reset when throttle  body,  MAP,  TPS,  ISC  or  ECU  has been reinstalled.


TPS/ISC RESET PROCEDURE

1.  Put  the  side  stand  up  and  engine  stop switch is at “RUN”.
2.  Turn the key to the OFF position.
3.  Fully open the throttle.
4.  Turn the key to the ON position.
5.  Release the throttle after waiting for eight seconds.
6.  Turn the key to the OFF position.
7.  Turn the key to the ON position.
8.  TPS and ISC have been reset successfully.

If fail to reset, repeat the steps from 1 to 8.