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TPS adjustment

Old 12-18-2006, 10:16 AM
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TPS adjustment

Checked my TPS last night. Gave a reading of 860 ohms. So removed screws with sharp chisel.. Made a notch..spun the out very easy. By using the slots in the TPS body..got it down to 575 ohms. To get down to spec. 430-440, I decided to gently and very slightly bend the tab on the Throttle that the TPS fits into..Then I set it at 437 ohms. That seemed like a simpler and safer way to get the needed adjustment rather than grinding out the slots. Your idle speed will change that reading of course, need to set idle speed and carb sync in spec...before you go after TPS setting..all makes sense now...

Take Care
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Old 12-18-2006, 10:27 AM
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I hope it works better for you than it did for me. I ended up setting it back to the high OEM setting as the only noticeable change I felt was a softening of the power, not a desirable outcome.

cheers
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Old 12-18-2006, 11:39 AM
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Tps

If I remember correctly, I read a comment from you before about this. It seems that the majority have felt an improvement. The manual recomends this as have some knowledgeable folks..But you never know..Mine is in winter hibernation until April...Will see.. Many variables.. What did you do to your airbox?? The previous owner of mine must have had some friendly mice..Wreaked a little havoc in the airbox..Patched up most of it..trimmed some of the rubber snorkel that sticks into airbox..little beggar really liked rubber...

Take Care
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Old 12-18-2006, 01:32 PM
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Yep, I tried the mod, went in with an open mind and hoped for results similar to what others had but was disappointed in the end. I realize that every bike is unique and so it may have worked for others. In my case, the engine was not any smoother (my main rason for trying it), nor did I achieve any fuel economy improvement or any performance gains (in fact, the instant hit taht I have come to love with my VTR was dampened noticeably). The beauty of such "mods" is that they are very inexpensive and can be easily reversed. I am glad I tried it because if I hadn't I would have been left wondering what if? Now I know that on my VTR anyhow it was a waste of time

In terms of the airbox mod, do a quick search (under Bernie Morgan) as I believe it was detailed in a post a short while ago.

cheers
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Old 12-20-2006, 03:45 AM
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Factory Pro have some info on the VTR on their website. They say you must reset the TPS.

Mikstr, I respect your opinion, however do you think it's possible that your "feeling" when riding the bike may have been giving you inaccurate info?

I know a bike with a power dip can often feel more powerful because of the spike in the power delivery. You feel the hit and think it is better, but it may not be. Can be hard to pick up some times. Like a two stroke compared to a four. The two stroke gives a big hit, and feel awesome, but away from that power band you are making less power then the four stroke engine.

Just a thought.
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Old 12-20-2006, 06:27 AM
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Hi Shayne,

I will be the first to acknowledge that the "seat of the pants dyno" can often be misled. However, I was fairly methodical in my approach (especially when going from the proper to the elevated setting) and noticed that I seemed to "get the hit back" (and noticeably so)when I undid the change. Now that I have bolts in place (that can be easily loosened to allow for a re-adjustment), I may re-try it.

I can relate to your comment about a two-stroke type hit. My job involves, among other things, testing snowmobiles for a living (and writing about it for a magazine rad by over 120,000 readers) so I am not only familiar with the two-stroke type "hit" (and quite enjoy it I might add), I have also had the opportunity to hone and use my seat of the pants teting skills (although this clearly does not make me infallible). In this particular instance, the hit I am referring to it felt at 3000 or so rpm, making it largely unrealistic for it to be the result of a contrast from a weaker power range at a lower rpm.

Again though, I may just have to re-try it. It is free after all
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Old 12-20-2006, 07:12 AM
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Tps

Interesting comments.. Kind of along the same lines..I had a Valkyrie just before I got the VTR. There is a very active and helpful site for the big Valk..greatest Harley humiliator known to man..Anyway, some guy devised a set up your wired into the electrical circuit. What it did was change the info coming from the engine temperature sensor to the ignition module and make "it" think the engine was still cold. What happened was you had more ignition advance until you hit 3100 rpm..then it dropped back to the normal ignition map...It changed the 1000-3000 punch enough so that the big Valk would leave a blacky if you nailed it in first in that rpm range. The down side was..if you were cruising below 3100 you had too much advance..the plug read was a little concerning..so I disconnected... the diodes to make the change cost $4.00...about 30 minutes with knife, soldering gun and tape.. I see you can buy a triggering wheel that increases advance all through the range...the neat thing about this other mod..it only affected bottom end.. Anybody ever toy with that??

Take Care
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Old 12-20-2006, 11:00 AM
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Unfortunately since our bikes are carbureted, our sensors and alterable variables are significantly less than that of a FI bike. Timing is picked up by the sensor on the right side by the clutch. I don't think coolant temperature is even an input to the ECM, just sends the signal to the guage. And then you have the TPS. That's about all I can think of on this bike. Oh, and rpm of course.
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Old 12-20-2006, 11:41 AM
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All the Superhawk TPS does is regulate the onset of ignition advance. It's a dead simple device.
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Old 12-20-2006, 11:51 AM
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Tps

Actually the Valk has 6 carbs...yup counted them many times. The ignition had greater advance when engine was cold. When you had the diodes wired in the engine idle speed would jump 300 rpm when you put it into gear. If you were sitting at a stop light...often kick it into to neutral to drop engine speed. This had nothing to do with a TPS, it was a signal from engine temperature to to the ECM... If you want to take a look just go unto the Valk forum..look up ECT Mod...kind of interesting..basically some free power.. Major boost at bottom end...In slow speed settings..engine was too advanced, if you kept rpm below 3100 ..say in 5th at 55 mph... After I had done this..took out unto street...left a roll on blackie with wife on the back...She gave me heck for hurting her neck... I wonder if the VTR has a similar set up???

Take Care
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Old 12-20-2006, 12:08 PM
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Well since you have tried it on your Valk, why don't you try it on your VTR and tell us the outcome.
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Old 12-20-2006, 02:28 PM
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Tps

Could I try it on your bike first? Actually, I am not confident in electrical matters...I copied what another had figured out. I don't know if the VTR has that kind of info input into an ignition module. Does anybody know about that?

Dave
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Old 12-20-2006, 10:00 PM
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Not that I have ever heard of.
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Old 12-20-2006, 10:46 PM
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Dave, good call on this one. I'll retract my earlier statement about the coolant sensor. I looked at the wiring diagram and indeed the output for the coolant temp sensor (ECT) goes right into the Ignition Control Module. What's even more interesting is that the output of the TPS taps into that same wire! These two voltages are added together when you join the two wires.

So, both ECT and TPS are a form of resistance, and when a voltage is applied then this reduces the voltage by some value. The lower the resistance, the higher output voltage.

Now, all temperature sensors pretty much work the same way. The hotter the sensor the more resistance it has. HOWEVER, the specs for the ECT sensor are reverse that of what I originally thought. The spec at 68F is 2000-3000Ω and at 178F it's 200-400Ω, thus less voltage is on the output of the sensor when the bike is cold.

Now, it makes perfect engineering sense to allow a motor more advance when cold, because it is farther from preignition (knock) and combustion temperatures are lower. Thus we can conclude that the lower the voltage into the ICM, the more advance it gives us. However this makes absolutely no sense because it goes against everything I've learned, experienced, and read about TPS. Read on.....

First the basics. The TPS is essentially a load sensor on the motor. The more the throttle is opened the more load there is (obviously). Now at smaller throttle openings there should be more advance on the motor. This allows spark to occur earlier, giving the combustion process more time to occur and more complete burn. This will result in better gas mileage as well, and better throttle response.

Now this is what gets me confused. Per the service manual (which may be wrong BTW), the TPS has it's minimum resistance at fully closed position, thus maximum voltage at the output at idle, and less ignition advance. The bike will have less advance at smaller throttle positions (low engine load), This also makes no sense since it is fairly widespread knowledge that there is an advantage of better throttle response to having the TPS set at a lower value (400-430 Ω), vice the normal 800-900Ω.

This whole discussion can be summed up in one simple table:


...............State.....Resistance.....Voltage.....Timing
ECT...........HOT...........LOW...........HIGH.... ...RETARDED
ECT...........COLD.........HIGH...........LOW..... ..ADVANCED
TPS...........SHUT.........LOW...........HIGH..... ..RETARDED
TPS...........OPEN.........HIGH...........LOW..... ..ADVANCED


So, I have a request here. I need to verify the service manual, because I think it must be wrong. Would someone who has recently adjusted their TPS please verify that the minimum resistance is present at closed throttle.
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Old 12-21-2006, 05:14 AM
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Tps

Hey Greg;

Your technical knowledge is amazing. I just set my TPS. The more the throttle was opened the higher the ohms. I got mine set down to 439. You might get some insight from checking the Valk Owners Forum. I'll go on my computor at work and check that again..find the thread. It's called the "ECTMOd"...pretty complete....It made a substantial difference in the bottom end.. My concern is that it left too much advance.. Some guys on that site where wiring in a tuneable rehostat to turn it down to normal in city traffic in the heat etc... I'll try to post that in a hour or so...

Take Care
Dave
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Old 12-21-2006, 06:38 AM
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based on the last two posts then, it would seem that leaving the TPS at the high setting would advance timing at lower rpm and thus improve engine response (which is exactly what I felt seat of the pants). Also, it is in line with Factory Pro (and others) offering an ignition advancer and claiming better response.

Hmmmmmmm, I may just leave it as is then.
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Old 12-21-2006, 08:03 AM
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Tps

Hey Greg

If you want go to valkyrieriders.com then go to shop talk..then scroll down till you see ECT Mod...a person could ask questions on that site as well. Lot's of guys on the Valk site were installing 4 or 6 degree trigger wheels, the Larger Interstate ECM unit and changing to lighter Interstate springs in the C/V's to make for snappier bottom end. With the VTR gains might be in just getting it set correctly not putting in more advance at the bottom.. The Valk engine is a torque monster at the bottom.. and still yanks hard at the top for such a big bike. If I recall the theory was more advance at the bottom (like a cold engine) then a drop to normal advance right around 3100 rpm. Guys were finding their top end was doggy if they used the 6 degree wheel..good at bottom..not good at the top....The VTR might not pull right with too much advance at the bottom... Mikestr's comments might be coming from the rpm where the advance reachs the right level by rpm..thus his "hit". Interesting that Factory Pro..offers a 4 degree wheel..most successful on Valk..that advances ignition from top to bottom... In the Valk you had to switch to Premium gas with any ignition mod.. or you would damage the engine...I saw some very bad signs of heat on my plugs so removed it..though I loved the yank at the bottom. I'll check back later..

Merry Christmas everybody
Dave:-D
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Old 12-21-2006, 10:05 AM
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Okay, then the service manual is correct. This makes absolutely no sense to me at all. Why would you advance a motor under high load, or similarly, why advance a hot engine (if my assumptions are incorrect and lower voltage results in less advance)?

The only way to figure this out is to actually check the timing with a timing light cold and hot, and check it again as the throttle is opened. It's possible to do, however I have no timing light. Maybe I can borrow one from the neighbor....
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Old 12-21-2006, 10:39 AM
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Tps

Hey Greg;

The stock Honda system on the Valk..advanced the timing when the engine was cold..ECT, from o-3100 rpm,then retarded advance after engine was warm. But..even when cold the advance got retarded after 3100 rpm. I still have my Valk manual..going to see if it has a TPS...I don;t recall seeing one. Mikestr has quite a few mods in his engine..lightened fly wheel..more sensitive..more likely to have a "hit". The improved running in the VTR's case, at the bottom maybe a matter of harmony in the engine, that's where it was designed to run right...pinging is not making power..to much heat or advance. If the TPS is set right it is feeding the needed advance in harmony with the fuel/air mix...if it's off.. if maybe too much...??? The guy who did the ECT mod. on the Valk may have some insight..I'll try and connect with him and ask the right questions..

Take Care
Dave..:-D
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Old 12-21-2006, 10:45 AM
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Hi again,

I did not have the lightened flywheel (or Flo-Commander) installed, nor the modded intake runners when I tried the TPS adjustment. I was running the (Bernie Morgan) airbox mod, DJ jet kit and Micron slip-ons only. I run my VTR on 87 octane and have never had a problem with pinging of any kind. Although I have not visually inspected my plugs either, my dealer made no mention of anything odd when replacing them which would indicate that the colour was good.

One last thing, the "hit" I refer to is not a peaky or coming onto the cam type of power rush. What I am referring to is an instantaneous and potent response to throttle input (this was dulled noticeably after the TPS adjustment)

Enjoying this discussion btw
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Old 12-21-2006, 01:55 PM
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I can confirm that when set up on the bench for testing purposes, my TPS showed low resistance ie 430ohms at closed throttle, and increased resistance ie 1100 ohms (I think it was about 1100, as this number wasn't the important one) at full throttle.

So what you say is correct Greg.
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Old 12-21-2006, 02:40 PM
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- Quoted from the Service Manual:

SERVICE INFORMATION
General:
- The ignition control module (ICM) varies ignition timing according to the engine speed. The engine coolant temperature (ECT) sensor and throttle sensor signal the ICM to compensate the ignition timing according to the coolant temperature and throttle opening.

I still don't understand this. It may be a "harmony" thing, as Dave suggests, but still goes against reasoning. Why, if the two voltages are added together electrically, would they oppose of each other if they are trying to achieve the same goal? I'll have to think about this more and maybe do a theory to practice by tapping into that green/black wire while changing the input parameters.
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Old 12-23-2006, 09:25 AM
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Tps

Hi Guys
Been on the road for two days..missed the discussion. The Valk does not have a TPS. It's igniton is advanced when cold only by ECT...After wiring in kit, the way to check whether you had it alright, was to warm engine, then with clutch in..drop it into first..if you were correct in your wiring.. the tach would jump 300 rpm....Greg have you looked at the Valk site?...

If I don't "see" you again before Christmas Day..Merry Christmas guys
...God Bless you and your families and friends...Bless our armed service folks and keep them safe..
Dave:-D
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Old 12-23-2006, 05:24 PM
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No, haven't been to the Valk site yet. Since it's the TPS that has me all worked up I think we're going to have to work that out on our own.
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Old 12-31-2006, 03:07 PM
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Tps

With the little wife helping, I took reading at closed throttle 450 ohmns (after adjustment from about 860) thenm began to open the throttle..at wide open it was past 2000 ohmns..going to go and check it all again...Some thoughts..if it is set at 860 at closed throttle or 460..when throttle is wide open it goes to?????I'm going to go and see if the ohmns are higher if it starts at 860 or whether it always ends the same...This is merely a Throttle Postion sensor..not engine speed..so the improvement when set right will be at partial opening or a rolled on throttle..not if it is yanked WFO..So I'm going to check for max...at two different starting points.. I will be back

Dave....
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Old 12-31-2006, 04:35 PM
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Tps

Well..here's what I found out..
With TPS set at 500 ohms at closed throttle showed 4,700 at WFO
With TPS set at 800 ohms at closed throttle showed 4,900 at WFO

Mikestr..where was your "hit" evident? When you snapped the throttle open from bottom up or in the mid-range with throttle snapped open???

I'm thinking the engine might transition better with throttle rolled on if the TPS
is set according to spec..but that correct setting would have little impact if the throttle is yanked open (shameless demonstration of immaturity)

I will try and grad settings at a varity of throttle settings to see what is happening...

With the Valk ..too much advance killed the top end.. 6 degree wheels
.. wonder if the VTR jumps at the bottom with say 800 ohms TPS reading at closed throttle..but then get's unhappy with higher revs...

Thoughts???????????????????

Well got to get ready for New Years Eve party..
Happy New Year's guys..bless you and your families
Dave
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Old 01-01-2007, 07:17 AM
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ECT mod

I tested a ECT mod back a few years ago (seat of the pants only).
Didn't notice any differance. But this was after setting the TPS to 430 ohms.
Put it back to stock configuration.

For what it's worth,

~Jeffers
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Old 01-01-2007, 09:17 AM
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Dave,

Seems you have your bike apart more than mine. Any chance you can tap into the green/black wire that goes into the ECU and measure voltage across ground while the bike warms up at idle. My guess is that it will increase as the bike gets warmer, but I'd like to verify that. Also, after the bike is warm test the same voltage as throttle is opened to varying degrees. I'm not sure if the bike has to be running or not. If it does then I'm sure we can get enough data with using closed throttle and 5000 rpm positions of the throttle.
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Old 01-01-2007, 12:58 PM
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Tps

Hey Greg;

I would love to oblige you but my is not running at present. I'm going to replace my CCT's with APE's before I put airbox and tank back on..I also broke one of my enriching circuit cable housings so waiting for a new one. So it will take me a while..sorry about that. Been thinking lot's about my experience with the Valk... when I did the ECT mod..which advanced timing up till 3100 rpm..The idle was lumpy..kind of like race cam...but being a six is wasn't rough feeling...The VTR might run ragged with non-spec TPS settings even though it may snap up a little better..You can see our friend tried the ECT mod on the VTR and found little difference. I wonder if gear position is also in the mix. The Valk only kicked into ECT mod. "mode" when you put it into gear... in neutral it dropped back to stock setting..put it in first and the engine speed jumped 300 rpm. It's interesting that in the Manual one of the ways of testing the TPS is to unplug the connector..run the engine to a constant 3500 rpm and then plug it back in..which should increase engine speed.. In the Valk which had no TPS the ECt mod had a specific engine speed range impact, whereas the VTR is responding to throttle position and engine temp. and perhaps being in gear...I wonder why mother Honda sent out so many VTR's improperly adjusted???

Dave
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Old 03-16-2009, 04:29 PM
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Greg,

I just cleaned and adjusted my spare set of carbs. I set the TPS on my original set at 500 Ohms (.500 see below for explanation) but saw you recommended below 400~430 Ohms. Now I have now adjusted the TPS on the bench connected to the upper and middle "pins" directly on the TPS. Does this matter? Strange thing is, and maybe it is related to my auto-ranging multi-meter, but the reading I got at closed throttle is .415 Ohms not 415, and at full throttle about 4.18 Ohms not 4018. Is setting it at 415 (or .415) correct at the TPS and why is it reading point 415 and not 415.00?

Thanks

Originally Posted by Hawkrider View Post
Dave, good call on this one. I'll retract my earlier statement about the coolant sensor. I looked at the wiring diagram and indeed the output for the coolant temp sensor (ECT) goes right into the Ignition Control Module. What's even more interesting is that the output of the TPS taps into that same wire! These two voltages are added together when you join the two wires.

So, both ECT and TPS are a form of resistance, and when a voltage is applied then this reduces the voltage by some value. The lower the resistance, the higher output voltage.

Now, all temperature sensors pretty much work the same way. The hotter the sensor the more resistance it has. HOWEVER, the specs for the ECT sensor are reverse that of what I originally thought. The spec at 68F is 2000-3000Ω and at 178F it's 200-400Ω, thus less voltage is on the output of the sensor when the bike is cold.

Now, it makes perfect engineering sense to allow a motor more advance when cold, because it is farther from preignition (knock) and combustion temperatures are lower. Thus we can conclude that the lower the voltage into the ICM, the more advance it gives us. However this makes absolutely no sense because it goes against everything I've learned, experienced, and read about TPS. Read on.....

First the basics. The TPS is essentially a load sensor on the motor. The more the throttle is opened the more load there is (obviously). Now at smaller throttle openings there should be more advance on the motor. This allows spark to occur earlier, giving the combustion process more time to occur and more complete burn. This will result in better gas mileage as well, and better throttle response.

Now this is what gets me confused. Per the service manual (which may be wrong BTW), the TPS has it's minimum resistance at fully closed position, thus maximum voltage at the output at idle, and less ignition advance. The bike will have less advance at smaller throttle positions (low engine load), This also makes no sense since it is fairly widespread knowledge that there is an advantage of better throttle response to having the TPS set at a lower value (400-430 Ω), vice the normal 800-900Ω.

This whole discussion can be summed up in one simple table:


...............State.....Resistance.....Voltage.....Timing
ECT...........HOT...........LOW...........HIGH.... ...RETARDED
ECT...........COLD.........HIGH...........LOW..... ..ADVANCED
TPS...........SHUT.........LOW...........HIGH..... ..RETARDED
TPS...........OPEN.........HIGH...........LOW..... ..ADVANCED


So, I have a request here. I need to verify the service manual, because I think it must be wrong. Would someone who has recently adjusted their TPS please verify that the minimum resistance is present at closed throttle.
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