[FZ6R]

mod edit: Since this has got to be such a lengthy thread, and this is the largest single issue that we deal with on our FZ6, I am going to attempt to summurize all the useful information from this thread in a single post. This it in attempt to make it easier for members to get the information they need easier for this issue. I hijacked this first post of this thread to make it easy to find. -jcaesar

Throttle Position Sensor (TPS) Issue Summary

What is the TPS?

Originally Posted by Runner-FZ6

The TPS Sensor is just a potensiometer.

It is actually a variable resistor just like the one found on a Volume control on your stereo system.

The the low side gives abrupt and unpredictable off-spec values, because it is this part of the potensiometer that is mostly used. Simply, this part of the potensiometer is worn out!
In fact Segue00 measured the loss of contact in that area.
The same phenomenon happens when a worn Volume potensiometer causes noise on your speakers.

I am not sure that this is the cause for the "binary" throttle response.

The service manual says that the TPS angle (Page 7-31) should be adjusted so as the TPS voltage should be between 0.63-0.73Volt.

So having a healthy, and properly adjusted TPS, we should measure 0.63 to 0.73 Volts when iddling.
If the value was 0 Volts, yeap that could cause that "on-off" response.

What Does the TPS Look Like?
Here is a bunch of good photos taken by Moldmaker of the TPS. He even included photos of the TPS torn down.
http://forums.sportbikes.net/forums/...&postcount=366
http://forums.sportbikes.net/forums/...&postcount=367
http://forums.sportbikes.net/forums/...&postcount=368


What does the TPS do technically?

Originally Posted by greatzipp's orginal question

I've been thinking about this for a week now and can't figure it out. So someone explain this to me or point out the error in my thinking.

Now, your TPS is desinged to tell the ECU how much your twisting the throttle so that the ECU knows how much fuel your injectors should spit out.

The TPS puts out a steady voltage at idle and increases as your turn the throttle. The voltage coming out of the TPS is translated into a signal by the ECU as to how much gas to inject.

At an idle your TSP puts out a steady .7 volts (about) which translates into throttle closed. Not 100% sure what the voltage is for fully open so let's just say 3volts = fully open. So more volts = throttle open more which = more fuel injected ...... right?????

Now let's say your TPS fails for some reason, doesn't matter what. According to the manual the fail safe for a TPS is to fix it at fully open ..... in this state the bike is still ridable.

But now the ECU thinks that the throttle is fully open so wouldn't it inject the amount of fuel = to WOT?? If the ECU thought the throttle was fully open wouldn't your RPM's stay high even if you let the throttle grip go?? Or would it still be injecting the max full for WOT but because the throttle bodies aren't open the fuel air mix is off so the result would just be really poor gas milage and maybe some julty riding caused by unspent fuel due to incomplete combustion.

Originally Posted by Dr. Honda's Response

Hummm… where to start…

OK… the TPS is only a pawn in the fuel injection game. The real leader is the MAP sensor. (Manifold Absolute Pressure) Yamaha calls it the “Intake Air Pressure Sensor.” This little device looks at manifold vacuum. The manifold vacuum is compared to atmospheric pressure by the ECU, and this will give the ECU the Air density of the incoming air charge. The air density, along with the engine RPM with be taken together, and the ECU will look up the injector pulse length on a look up table. (doing it thousands of time a second) Oh… I should also say that the air intake temp also plays a small part in this too.

The only thing that the TPS is really doing is letting the ECU know if you are opening, or closing the throttle. This is important because on a modern, high performance engine, as you quickly open the throttle you need more fuel than the apparent lode will dictate. (map and rpm look up) This is know as “Tip In Fuel” or as it was known on a carburetor… “The accelerator Pump.” Without the tip in fuel… the engine would (minimum) cough and flame out. (too much air) At worst… the engine would have HORIBLE detonation, (pre-ignition) and burn holes in the tops of the pistons, crush the ring lands, bend the rods, or crush the crank bearings. (lot’s-O-bad stuff)

So… when the ECU can no longer reliably read the TPS, the ECU goes into “limp mode.” Limp mode on our FZ6’s is basically running it in it’s Warm-up mode. The added fuel of the warm-up cycle will keep all the bad stuff listed above from happening. (it’s like in permanent acceleration or "choke on" mode)

OK… we don’t like the crappy fuel economy, the smelly exhaust, or the fouled sparkplugs… but they are cheap compared to a blown engine. Personally I think once it can’t read the TPS it should run a bit leaner, but limit the RPM’s to around 7k.

For more discussion on how the TPS technically works, see this thread:
http://forums.sportbikes.net/forums/...d.php?t=291973


How to Replace the TPS:

FZSilver did a great job of summurizing the replacement of the TPS, complete with photos.
http://forums.sportbikes.net/forums/....php?p=2229422

What are the Symptoms of a Faulty TPS?

• Stalling
• Irregual idle
• RPM Drop while acclerating or trying to maintain a constand speed.
• Drop in fuel Mileage
• Poor Throttle Response

How to test the TPS:

Originally Posted by Megatron

To check the TPS values, you have to press and hold SELECT + RESET, then turn the key and keep them pressed for 8 more seconds.

It'll appear dIAg on the display, you can release them now. Afterwards use select until you see a d01 (Diagnostic Mode for the TPS)

Then it should read between 15 and 17 if the throttle is closed,
With the throttle fully open, it should read between 97 and 100.

If the values are over or below those I mentioned, the TPS should be replaced.

To leave the dIAG mode, simply turn the key counter clockwise.

For more discussion on testing TPS, see this post:
http://forums.sportbikes.net/forums/...&postcount=247

Some Notes That You Might Want to Consider:

Originally Posted by segue00

1) Although replacing a faulty TPS may solve the problem, it might be something else that causes the TPS to fail.
2) Some bikes had multiple TPS replacements.
3) Most bikes did not have this problem.
4) Some bikes reportedly that had the TPS symptoms did not get fixed by just replacing the TPS.
5) Going into diagnostics every now and then and making sure that the spec value on the throttle of 16 - 100 percent does not change is one way to monitor whether your TPS is changing.
6) It's still a crap shoot, and the odds are that very few throttle position sensors becomes faulty. At least going by the sampling in this forum and on the current number of complaints in NHTSA reports.
7) At least 1 TPS was installed incorrectly upon replacement. Something to do with the o-ring placement.
8) The original TPS had been superceeded by a revision and carries a new part number.
9) So, if you're going to replace your TPS, at least make sure they don't put in a TPS with the old part number. Or ask for the TPS for a 2006 release model or later if you have an '04 or an '05.

What Actions You Should Take to get Yamaha to Address This Issue:

• Contact Yamaha Customer Service. We need as many people as possible to contact Yamaha about this issue. Hopefully they will address it and issue a recall.
• File a complaint with the National Highway Traffic Safety Administration (NHSTA) - For those that are in the U.S.
  http://www.nhtsa.dot.gov/cars/problems
• For those not in the U.S, please file with your local Traffic Safety Adminstration.
• Sending your faulty TPS to segue00. segue00 is tearing down the faulty TPS and trying to find the root cause. So far he only has a couple, and hasn't been able to nail down the exact root cause with the few he has.
  
  Also, Jamez is collecting details to submit to the NHTSA and Yamaha to see if we can push this thing to at least a Technical Bulletin if not a Recall.
  
  So, if your TPS has been replaced (either by yourself or by a dealer), please PM Jaez the following information:
  
  

  1.) Your Name, City, State/Province, Country
  2.) Your FZ6 year
  3.) When was your TPS replaced
  4.) Who replaced your TPS (you/non-dealer or dealer)
  5.) The Part# of your replaced TPS
  6.) Attach a copy of your service receipt (if you can/have it)
  7.) Send me any additional information that I have not asked for that you think would be helpful for this cause

  
  If you have any questions about gathering all this info to send to Yamaha or NHTSA, please PM Jamez.

What can I do to convince the Dealer to replace the TPS if they say there is nothing wrong with it.
The dealer may not be willing to replace it under warranty, because the fault code is not logged. You can force a fault code by disconnecting the TPS, and then turning on the bike. It should log a Fault Code 15.

Also, have them test the resistance of the TPS and make sure that it is within spec.

What part TPS part number is the latest one that I should install to correct the issue.

The TPS should be replaced with the 3rd Generation part no. 5FL-85885-02-00.