Tach Doesn't Always Reset

[Dale2010]

A few weeks ago, I posted under another topic discussion, problems I've been recently having with my clock. As no one seems to know for sure what is behind the problem, I've become somewhat paranoid and have been looking for any signs that something else (electronically) might be happening at the same time.

I just noticed that my tach does not return to zero on shut down. If I simply turn on the ignition and then turn off the key, the tach zeros, as long as the engine hasn't been running. If the engine was running before turning off the ignition, the tach returns to 1500.

I can't remember if this happened before or not.

My bike is a 2010 FJR and so far, everything else (except the clock) seems to be running OK. Anyone else experiencing this situation?

Thanks

 

[wfooshee]

The tach is controlled electronically, and no one here really knows how for sure. There's not a "tach" signal from the ECU or ignition system. the ECU and the meter cluster are sort of a computer network.

One begins to wonder if you have a fubar'd gauge cluster.

It may also be possible that the gauge cluster powers off before the ECU somehow (wouldn't begin to make a guess on that, though) in which case freezing at the "current" RPM might be normal.

 

[Dale2010]

The tach is controlled electronically, and no one here really knows how for sure. There's not a "tach" signal from the ECU or ignition system. the ECU and the meter cluster are sort of a computer network.

One begins to wonder if you have a fubar'd gauge cluster.

It may also be possible that the gauge cluster powers off before the ECU somehow (wouldn't begin to make a guess on that, though) in which case freezing at the "current" RPM might be normal.

Thanks for the reply and comments. I guess what I would like to know at this point is whether or not anyone else's tach is exhibiting the same trait, or if this is particular to my machine. As mentioned, the tach returns to 0 if the ignition is turned on and then off without actually starting the engine. However, if the engine is running and then the system is shut down, the tach returns (so far) to ~1500 RPM.

I simply can't remember if my bike did this before. I don't think so but I'm not sure. I'm afraid that you might be right and the panel is FUBAR and the best(?) might be yet to come.

 

[ionbeam]

The tach should always return to zero if the engine is not running. The meter assembly has two modes, self-running and ECU commanded. Things like the odometer reading and clock are internal to the meter assembly; the tach and speedometer get their commands from the ECU. The ECU sends signals to the meter assembly via serial communications. The gauges are actually servo motors commanded by the ECU.

The communication between the ECU and the meter assembly is 'open loop', the ECU sends a command but does not follow up to see if the command was executed correctly. The serial communication system is monitored to confirm that the basic signal system is working but it does not verify the commands were followed. If the meter assembly has fundamental communication errors with the ECU the meter assembly will display Er-1 to Er-4 depending on the communication failure. If your meter assembly does not display any of these error numbers then the ECU and the meter assembly are communicating correctly.

If you check your diAG for error codes there is Fault Code #50 which is a code for an ECU malfunction that may not display until you look at the diAG. This is an indication that the ECU is not executing the internal software correctly. The odds of this being the root cause of your malfunction is low.

A clock that stops running but does not reset to 12:00 and a tach that does not return to zero are strong indicators that the meter assembly is malfunctioning.

 

[mvette]

The tach is controlled electronically, and no one here really knows how for sure. There's not a "tach" signal from the ECU or ignition system. the ECU and the meter cluster are sort of a computer network.

One begins to wonder if you have a fubar'd gauge cluster.

It may also be possible that the gauge cluster powers off before the ECU somehow (wouldn't begin to make a guess on that, though) in which case freezing at the "current" RPM might be normal.

Thanks for the reply and comments. I guess what I would like to know at this point is whether or not anyone else's tach is exhibiting the same trait, or if this is particular to my machine. As mentioned, the tach returns to 0 if the ignition is turned on and then off without actually starting the engine. However, if the engine is running and then the system is shut down, the tach returns (so far) to ~1500 RPM.

I simply can't remember if my bike did this before. I don't think so but I'm not sure. I'm afraid that you might be right and the panel is FUBAR and the best(?) might be yet to come.

It sounds like to me the tach on the low end of the scale while idling simply has a slight bind in the servo motor, which wont allow the needle to fall back to zero when engine is switched off. When on power up with the ignition switch, the needle swings wildly from zero to full scale and back with a lot of inertia to overcome the bind at the end of the scale when falling back to zero.

 

[supertankerm60a3]

Ionbeam has the best overall explanation. I would simply say that the odds of two odd symptoms within the same assembly not being related are REALLY low. On the bright side, that panel is (relatively) easy to replace and they do come up on EBAY fairly often.

 

[Dale2010]

Ionbeam has the best overall explanation. I would simply say that the odds of two odd symptoms within the same assembly not being related are REALLY low. On the bright side, that panel is (relatively) easy to replace and they do come up on EBAY fairly often.

Thanks to all those who have jumped in with suggestions.

As for getting a meter assembly, the odds decrease significantly for Canadians as we have the metric system (Km instead of miles, degrees C instead of degrees F, etc.). Actually I had sourced one from the UK but then cancelled the order because of the problem with the constant metric to standard conversions which would be necessary.

 

[Dale2010]

The tach should always return to zero if the engine is not running. The meter assembly has two modes, self-running and ECU commanded. Things like the odometer reading and clock are internal to the meter assembly; the tach and speedometer get their commands from the ECU. The ECU sends signals to the meter assembly via serial communications. The gauges are actually servo motors commanded by the ECU.

The communication between the ECU and the meter assembly is 'open loop', the ECU sends a command but does not follow up to see if the command was executed correctly. The serial communication system is monitored to confirm that the basic signal system is working but it does not verify the commands were followed. If the meter assembly has fundamental communication errors with the ECU the meter assembly will display Er-1 to Er-4 depending on the communication failure. If your meter assembly does not display any of these error numbers then the ECU and the meter assembly are communicating correctly.

If you check your diAG for error codes there is Fault Code #50 which is a code for an ECU malfunction that may not display until you look at the diAG. This is an indication that the ECU is not executing the internal software correctly. The odds of this being the root cause of your malfunction is low.

A clock that stops running but does not reset to 12:00 and a tach that does not return to zero are strong indicators that the meter assembly is malfunctioning.

Thanks for the reply and information.

I understand that the error codes, in contrast to most automobiles, are simply displayed on the digital panel. Nothing shows at this point. How can I determine whether or not there is a fault if nothing is displayed? I'm unsure what you are referring to as the diAG.

 

[ionbeam]

How can I determine whether or not there is a fault if nothing is displayed? I'm unsure what you are referring to as the diAG.

The story of diAG (This is how the word Diagnostic is displayed on the LCD panel.)

 

[Dale2010]

As a brief follow up, I was never able to locate the problem which seems to affect the clock and tripometers. A trip to two Yamaha dealerships yielded zero results other than help me part with several hundred dollars.
It sure would be nice if Yamaha would provide some trouble shooting information for the instrument panel.

 

[un4gvn]

I believe ion spelled it out. The meter is bad.

 

[wmadoty]

I have seen it posted that when some members disconnect their batteries they will sometimes have a tack that moves off of zero. To go a little farther down this path, I have seen it written that if some members with Gen II bikes disconnect their GROUND wires their tach will move off zero. I also have a gen II and know that the 10's are not included in the ground recall, but I wonder?

I would check the grounds, battery to frame, and all the spiders. I would really look at the ones in the nose, as I would think they would be the grounds for the metering unit.

I would really want to check those grounds. I do not think that visual observation and a casual touch would be enough, I would really want to wiggle them and see that there was no corrosion.

Good luck and let us know what you find.

 

[Dale2010]

Thanks wmadoty for the reply and information.

I've checked the direct ground at the battery and all seems well. However, checking the spiders seems to be considerably more complicated. Without potentially damaging some of the wiring, I'm not sure how to go about such a procedure.

At this time of year, I'm hesitant to do much work on the bike as I don't want to chance having it 'laid-up' during our few weeks of warm sunny weather. However, if I can find a starting point, it may be something to tackle on stormy days or when the weather again turns cold in the fall and winter.

Thanks again...

 

[dcarver]

Ahh, the wait till winter syndrome...

Good luck on your project!