Tweaking the TPS

[C1xRider]

For the record, TPS stands for Throttle Position Sensor, while TPMS is Tire Presure Monitor Sensor (or System)

Several times the question has come up about adjusting the TPS on the C14, and so far no one has posted any information about results from doing it.  Well, here you go...

My bike always had a dead zone, or delay between the throttle plates opening, and the EFI and ignition kicking in.  It seems the ECU is a little bit delayed in response to the change in air flow caused by the throttle butterflies beginning to open.  The delay was most noticeable when in low gear, navigating steep down hill switchbacks.  While it is a pretty hard hit, it is not the same as the hard hit that all of our bikes do when you do a abrupt roll on of the throttle.

My bike also has terrible vibrations, and it's had them since day one.  The only things that have made a difference to the vibrations were things that affect the flow through the motor (ZX14 exhaust and a K&N filter have reduced vibs).  The vibs are worse in ECO mode.  Also, my bike gets average to pretty good fuel mileage, which I don't mind.

The TPS is mounted on the right side of the #4 throttle body, secured by a very soft (i.e like butter) aluminum security Torx screw.  It requires removing the side fairing to access it.  I started by adjusting the TPS clockwise, which would tell the ECU the throttle plates were more open then they were previously.  I only moved it about 1mm, and the results were not desirable.

The bike ran about the same with respect to power and how the engine responded, and the dead zone was gone.  However, I noticed the bike ran much hotter, as the temp gauge would be around 4 bars on a 70F day with low RPM cruising, and the cooling fan was kicking on way more then it should have been.  One example I noted was the fan came on while riding in second gear at about 25MPH, when the outside air temp was indicating 75F.  Also, the fuel mileage dropped a bit, as I expected, and engine vibration went up by a very noticeable amount.  The vibs were now about the same between ECO and non-ECO modes.  It had no affect on abrupt throttle openings that most would like to cure (as expected).

I ran the bike for several weeks with it set there, but decided the increase in vibrations, heat output, and the constant cycling of the cooling fans was not worth it.  I readjusted the sensor back to about 0.5mm from the original position, and this seems to be a good compromise.  The temps are back to where they were, the dead zone is still not obvious, and the vibrations are back down to about where they were (maybe just a little worse).

So, in short, unless your bike has symptoms like I described above, there really isn't any benefit to adjusting the TPS.

Hope this helps.

[VirginiaJim]

Are you talking about the subthrottle sensor?   I think it's adjusted via voltage measurements, isn't it?  There's big bold print in the manual that says don't muck with it as it has been precisely adjusted at the factory from the same nitwits that adjusted my headlights.  No good can come from DIY adjustment, methinks, unless you have the same equipment that Kwak had at the factory or it just comes pre-adjusted.

I think we had a thread where someone went to a dealership to get some work done and a well meaning tech 'tried' to adjust it and the bike got worse.  Voltage is .62 to 4.14vdc from closed to fully open.  Probably some magic and dancing that you should do when 'adjusting' this.

[B.D.F.]

I believe he is speaking of the Throttle Position Sensor, which is what monitors the position of the main throttle plates, not the sub throttle plates (or the 'flies' as we like to call them).

As far as adjustment.... it will lean or enrich the mixture by 'fooling' the ECU into thinking the throttle is open further or less far than it really is. Not all that huge a deal IMO as long as it is not moved too far. The fact that the OP's bike ran hotter is not a good sign though. But as far as 'us' moving it, as long as it is done with a reasonable understand of what we are doing and the results monitored (as the OP did) I would not shy away from tinkering with it.

Of course if one does not know what it does and what changes moving it will or may have then yes, one is simply mucking about and should probably leave well enough alone. It is unlikely a monkey with a screwdriver will happen to adjust a complex machine into a better state of tune.

I believe Kawasaki sets the position sensor based entirely on voltage output, not anything having to do with actual mixture control or monitoring. I believe those sensors are installed long before the engine is ever started and locked down into place. Just like the fuel map is installed into the ECU without the engine ever being tested for the real results of using that map on that particular engine. It is all a matter of 'close enough' and almost always IS close enough but often times could be somewhat improved given time and a better adjusting / results observation.

Brian

Are you talking about the subthrottle sensor?   I think it's adjusted via voltage measurements, isn't it?  There's big bold print in the manual that says don't muck with it as it has been precisely adjusted at the factory from the same nitwits that adjusted my headlights.  No good can come from DIY adjustment, methinks, unless you have the same equipment that Kwak had at the factory or it just comes pre-adjusted.

I think we had a thread where someone went to a dealership to get some work done and a well meaning tech 'tried' to adjust it and the bike got worse.  Voltage is .62 to 4.14vdc from closed to fully open.  Probably some magic and dancing that you should do when 'adjusting' this.

[Rocket Therapy]

TPS is set on voltage and by changing the voltage even slightly changes ECU settings, fuel delivery, timing etc.  not a good idea to just "tweak" it.

[Pokey]

I will be sure not to tweak mine, even ever so slightly.

[VirginiaJim]

Ok, I can't find a reference to a throttle position sensor.  Did they call it something else?

[B.D.F.]

Wuss.

Brian

I will be sure not to tweak mine, even ever so slightly.

[B.D.F.]

Yeah, Kawasaki seems to call it the 'Main Throttle Sensor' in the service manual. I guess that is as opposed to the sub- throttle sensor. Both terms are incorrect; the correct term is throttle position sensor as the OP mentioned.

The OP is also correct that in the general world using the acronym 'TPS' with regards to any vehicle would make one think of the throttle position sensor because it is the correct term and all modern vehicles have one; there are very few vehicles using tire pressure sensors on the wheels (auto systems usually detect a tire is low on pressure because it turns faster than the other tires on the vehicle).

All of that said, it is common for us C-14 owners to refer to the tire pressure sensors as TPS's. Technically wrong but it works because we mention them often (things like 'I just love my TPS system and would spend any amount of money to fix or maintain it!') and we typically do not mention the throttle position sensor.

Of course if someone were to refer to the TPS using a more generic term, such as "I just love it to death!" we would not immediately know if that person was thinking of the TPS system (Tire pressure measurement system) or KiPass....

Brian

Ok, I can't find a reference to a throttle position sensor.  Did they call it something else?

[VirginiaJim]

Kwak says give that the sign of the cross and back away quickly as well.  Whoah there, I'm wearing two crosses.  I guess I'll back away double quick.

[Pokey]

Wuss.

Brian

My fabulous 2008 runs great, well except for the stupid TPMS system.

[VirginiaJim]

I see an FJR in your future....

[Pokey]

I see an FJR in your future....

I see a Tenere in my future.   Love my C14 and hope to keep it too, but I am finding I enjoy the ADV style rides more.

[VirginiaJim]

 

[Rocket Therapy]

I see a Tenere in my future. ;)  Love my C14 and hope to
keep it too, but I am finding I enjoy the ADV style rides more.

ADV????

[Rocket Therapy]

ADV????

Adventure ....  gosh I'm getting slow LOL

[Conrad]

I believe he is speaking of the Throttle Position Sensor, which is what monitors the position of the main throttle plates, not the sub throttle plates (or the 'flies' as we like to call them).

As far as adjustment.... it will lean or enrich the mixture by 'fooling' the ECU into thinking the throttle is open further or less far than it really is. Not all that huge a deal IMO as long as it is not moved too far. The fact that the OP's bike ran hotter is not a good sign though. But as far as 'us' moving it, as long as it is done with a reasonable understand of what we are doing and the results monitored (as the OP did) I would not shy away from tinkering with it.

Of course if one does not know what it does and what changes moving it will or may have then yes, one is simply mucking about and should probably leave well enough alone. It is unlikely a monkey with a screwdriver will happen to adjust a complex machine into a better state of tune.

I believe Kawasaki sets the position sensor based entirely on voltage output, not anything having to do with actual mixture control or monitoring. I believe those sensors are installed long before the engine is ever started and locked down into place. Just like the fuel map is installed into the ECU without the engine ever being tested for the real results of using that map on that particular engine. It is all a matter of 'close enough' and almost always IS close enough but often times could be somewhat improved given time and a better adjusting / results observation.

Brian

For one monkey that would be true Brian. What about a thousand monkeys with a thousand screwdrivers? Now, put a Kawasaki technician shirt on these monkeys, now what are the chances?   

[gPink]

If someone with a PC V wanted to tinker with the TPS while connected to the software it might show what said tinkering is doing.

[Pokey]

Adventure ....  gosh I'm getting slow LOL

Nah you figured it out.    I really enjoyed my Vstrom, although I sure do like the power and shaft drive of the C14. I would honestly consider trading someone for a Vee 650 with title in hand, the 650 is a much more refined and dialed in bike than the 1000. Life is too short and too many bikes out there, I have enjoyed every bike I have owned.

[B.D.F.]

True but if someone had a PC V or PC III and wanted to tweak, that person could just do it in the table loaded in the PC already.

And anyone could tweak the TPS with nothing more than a voltmeter (or VOM) to watch the change. One could even write down the original setting and return to that place regarding the TPS.

Youse Guyze is makin' me wanna' go tweak something on my bike with all this tweaking talk....

Brian

If someone with a PC V wanted to tinker with the TPS while connected to the software it might show what said tinkering is doing.

[B.D.F.]

Oh yeah, how does that old quote go- 'If a thousand monkeys typed away at a thousand typewriters, we would end up with 492 variations of the Concours 14 manual' or something similar, right?

Brian

For one monkey that would be true Brian. What about a thousand monkeys with a thousand screwdrivers? Now, put a Kawasaki technician shirt on these monkeys, now what are the chances?