Switch for TPS

[William1]

Not that anyone gives a flying cr*p, but I created a wiring diagram and made the test version of switch/resistor setup.

[thedktor]

William - what bike are you testing on a 250 or 450??

[William1]

I am testing on a 08 WR250, but that should not matter.

[William1]

Arggggggggggg!!!!!!!!! Before I actually did a ride test, I ran the numbers with the meter. I discovered a few things.

1) I am becoming senile. The Yellow and Black wires are backwards. For the electronic types. the Yellow is the wiper, the Black is the neg, the Blue is the positive. Both resistors should be tied to the yellow and then a leg from one to the Black and a leg from the other to the Blue.

2) Even though the ohm is correct (the TPS 'pot' is about 5K ohm) and a 3.3k and a 2.2k ohm resistors equal about 5k, the voltage readings I got were NFG.

So my Drain Bamaged mind has hit a stupid block. Any real electronic wiz's, PM me. In the mean time, I'll make some calls to find a smart guy.

[ebrabaek]

Arggggggggggg!!!!!!!!! Before I actually did a ride test, I ran the numbers with the meter. I discovered a few things.

1) I am becoming senile. The Yellow and Black wires are backwards. For the electronic types. the Yellow is the wiper, the Black is the neg, the Blue is the positive. Both resistors should be tied to the yellow and then a leg from one to the Black and a leg from the other to the Blue.

2) Even though the ohm is correct (the TPS 'pot' is about 5K ohm) and a 3.3k and a 2.2k ohm resistors equal about 5k, the voltage readings I got were NFG.

So my Drain Bamaged mind has hit a stupid block. Any real electronic wiz's, PM me. In the mean time, I'll make some calls to find a smart guy.

And the verdict is...........??????? I`m cautiously optimistic:banana:

Erling

[William1]

The verdict is I am an idiot! Though many of you already knew this.

1) My measurents were correct. It is kilo-Ohms. My testing was flawed.

2) My wiring was incorrect but I have subesuently fixed it in real life and in the above drawing. When I fixed the wiring and retested, it was perfect.

Now, I have some personal chores to do like walk the dogs and get dressed, in that order (my neighbors keep thier kids inside all the time when I am out) and I'll do some real life riding testing today.

[123BigcoopDawg576]

The verdict is I am an idiot! Though many of you already knew this.

Indeed I did

I'll do some real life riding testing today.

Send me the harness you built and Ill test for you

In all seriousness...you did wonders, thanks for all your hard work!

[William1]

LOL, you laugh. My intention is to send off to a few TTers (the nice ones) and have them test it too.

It is plug and play as long as you can get to the TPS plug, it takes under a minute to install or remove. It has three settings. 'OEM', which means you use the TPS on the bike, 'Off' which is the same as having the TPS simply unplugged and 'BYP' which is the emulator mode, which tells the CDI you have the throttle at 3/4. Will be going out in about 30 minutes to give it the first test ride.

[William1]

Alrighty! Back from the test ride and I have mixed feelings. It does seem to of reduced the stutter somewhat. It seems to be about the same as with the TPS simply unplugged/switched Off, both in the amount the stutter is reduced and the performance hit when in the BYP mode.

With the TPS Off or in BYP, the bike idle increases about 200 rpm. My idle speed is about 1,850 normally and it climbs to about 2,050.

Next step will be to contact some select TTers and have them test it, report their findings and decide the next step.

[ranger85]

I applaud your effort, very interesting stuff, if you find this works well I may head to radio shack myself.

Thanks William for all the hard work.

[FORMA MOTO]

The verdict is I am an idiot! Though many of you already knew this.

1) My measurents were correct. It is kilo-Ohms. My testing was flawed.

2) My wiring was incorrect but I have subesuently fixed it in real life and in the above drawing. When I fixed the wiring and retested, it was perfect.

Now, I have some personal chores to do like walk the dogs and get dressed, in that order (my neighbors keep thier kids inside all the time when I am out) and I'll do some real life riding testing today.

:banana: :banana:

[William1]

Now for a lot of testing to see what works best and makes the most sense. Wil be a few weeks as the data is acquired. Again, this is a potential 'cheapo' solution for DS riders who simply want to travel pavement sections between trail heads and not have the stutter. It is not a good solution for a super moto rider or a rider who is on the street a lot.

[Summit Seeker]

William, dont be so hard on yourself, Let us pick on you.

[William1]

I PM'd GrayRacer513 this morning to bounce my concept off of him. He reminded me of a scenario I had completely forgotten about. A 'map' is based on variables coming in. With a bike like the WR, we have two values, the TPS and actual RPM. A 'map' (spreadsheet really) would state that if the throttle is at a certain point and the engine speed is at a certain point, use this much advance. The CDI calculates these values and locates the result on the map and if the resulting value is on the map, it uses the corresponding amount of advance. For example, the rpm is 9,000 and the TPS says 3.9v. A calculation is performed and the result is on the internal map of the CDI. It says to use X advance. Now, if the result is not on the map, be it from a faulty TPS, erroneous signal from the TPS or engine parameters way out of wack (for example, 2,000 rpm and the throttle wide open), the system reverts to a fail safe spreadsheet based solely on rpm, to prevent excessive advance at a low rpm.

Now.... I say all this because unless the engine speed is such that the 'bypass' signal creates a valid value on the internal map, the CDI will revert to fail safe, which is what I noticed yesterday. In essence, I do not believe the efforts expended to emulate 3/4 throttle will be worth while. But, I do not think the effort is a total waste. New knowledge only hurts a little.

I still will perform a few more tests on the emulator to confirm it is pointless. I tested yesterday with my CDI set to 'WR' grey wire and not the 'YZ' disconnected state. I'll do it in the 'YZ' mode this afternoon.

Additionally, SJMC_DON has graciously accepted being a tester too and I'll send off the device to him to confirm or refute me results.

[William1]

OK, I just completed the last series of tests. This series were done with the Grey wire disconnected. The stutter was much much worse. This leads me to conclude that perhaps, those that did not complain may not of disconnected the Grey wire or even been able to. There is significant difference in stutter between the WR (Grey wire disconnected) and YZ (Grey wire connected) choices. With the Grey wire connected, the stutter was not bad, tolerable in fact but disconnected, a frickin' nightmare.

So, with the Grey wire disconnected, the switch did have a marked effect though both the Off and Bypass setting seemed about the same across the board. The power 'hit' to having the switch in the BYP or OFF was about the same as having the Grey wire connected. Idle speed was affected as the it was in the previous test.This confirms some of the previous conclusions further.

Based on the results I got and expect to get from my (guinea pigs:moon: ) generous testers, this is what I think we will want to do:

No need for the resistors and all the wires, double pole triple throw switch.

A single pole, single throw switch on the yellow wire. Still considering options to make this setup 'factory', but it will be very simple and all the parts should cost under $50.00 at most and a cheapo solution could be about $10.00

Testing parameters:

Grey wire connected, Test in OEM, then Off then BYP, note results. This needs to be done at idle, 1/4, 1/2 and 3/4 throttle at steady speed and then accelerating where possible.

Then the same series of tests done with the Grey wire disconnected. Note amount of stutter, performance 'hit' and any other run anomalies.

Remember this is not a road solution, it is a band-aid to make transit stages bearable. It would be used after you are on the road and up to speed. The switch flipped to the 'no stutter' setting and left there till you either came to a stop or went back off road.

[SJMC_DON]

I am up to the challenge of testing as I am sure are the local police officers in my little town:busted:

Can't wait to try it out:banana:

Thanks William:ride:

[William1]

Just returned from the post office, it is enroute.

Just do not expect miracles. Expect to not be as upset.

I was a bit surprised at the difference the WR/YZ CDI Grey wire had on the stutter. I had never considered it till today as being a potential factor.

[ebrabaek]

Will.... As you once told me......" Isn`t R&D wonderfull"..... It take perseverance and motivation...... But once the goal is achieved...... It`s wonderfull..... Full screw all forward...

Erling

[bg10459]

I posted this in the Dynatek thread, but felt the discussion is better held here.

I just want to go on record: I've put a bunch of street miles on my 03 WR450 in the past few days, and I've been looking for the studder at various throttle positions, but I notice none. My grey wire is disconnected, and I normally jet my bikes for the season, but I didn't jet for the 100+ temps we're having here in TX right now, so I'm probably a bit rich. I set my TPS a few years ago and never touched it again, so who knows, it could be slightly off from the recommended setting. Has anyone tried setting their TPS to other than stock recommendations?

The emulator I made does just that.

As I understand it, the emulator is only providing a voltage that is equivalent to a "snapshot" of what the TPS would provide at a particular instance. Even with a rheostat, the voltage would still be a constant, just pick where you want it. What I'm suggesting is allowing the TPS to provide a variable voltage according to throttle position, but change the starting point, so to speak. In other words, shift the voltage range in which the TPS operates by setting it to other than stock recommendations and hopefully prevent falling between two values on the map .

My bike ain't broke, and I'm far too lazy to do any testing for fun. I'm not even sure it would work. I'm just throwing it out there.

[William1]

I understand. Let's say the stutter occurs mostly at 1/2 throttle. You make a device (easy enough to do) to 'shift' the TPS signal 25%. If in fact the issue was merely the TPS signal, the stutter would be moved to 3/4 throttle. You still have it. But (there always is on one or more) the way the CDI works is it expects values (RPM TPS = X) to always be in a certain range. If they are out of range , the CDI falls into the 'Fail Safe mode'. Shifting the TPS signal would do that, leaving you with the same result as merely disconnecting the TPS.

Bottom line is, when everything seems to be working properly, on a bike with the Grey wire disconnected, there is a range of throttle positions and RPMs that have the stutter. To not have the stutter, (at least so far in the testing) it appears you must change a variable.