Tach Problems - ECU shuts off?

[chunkygoat]

Hey guts, im wondering if anybody has heard of this issue. It seems tgat when I initially start the bike, first 5 minutes of riding, the tachometer bounces back and forth forth from 0 to 16k and shuts off and back on again almost like the startup routine.

Ive also had issues stalling when rolling off the throttle in 1st gear coming to a stop. I have heard of a TPS recall but im not sure if it is for my year. I have an 08 s2. I will try to record video of this while its happening.

Any input is appreciated guys. Has anybody heard or seen anything like this before?

 

[Motogiro]

TPS recall was for the older S1 05. Doesn't mean your TPS can't go bad but this sounds like an intermittent open either in the ignition switch or the wire that feeds that circuit. You might try to see if you can make it happen buy starting the bike and while sitting still in neutral, move the steering slowly from side to side to see if it effects the power fluctuation. Also check the plugs at the front of the bike where the harness goes into the frame.

 

[DavesFZ]

Could that be a ground issue at the Speedo? The bike runs fine, right?

 

[FinalImpact]

Cliff nailed it. I'd bet its in the steering area.
Q? Does the engine shut down or just the cluster "reboots".

In addition: I'd do the following:
You might also place the display in Diagnostics mode and do the static TPS read out. You're looking for smooth linear output as you VERY SLOWLY roll the throttle open and closed. Also do like 5 quick snaps to WOT and 5 snaps to FROM WOT to idle. The numbers should repeat exactly. Anyway - I don't see that as the reason your display restarts. They are not likely related.

For the display restart and performance issue:
Disconnect battery
Disconnect ECM - inspect, it unplugs easily
Disconnect cluster - inspect. Anything odd?
Remove both pod covers and inspect all connections by removing them.

IF NOTHING found in either location (Cluster won't help stalling), I'd pull the airbox, you'll need some hearty pliers, a very long 3 mm ball driver allen, and a phillips. Remove the airbox. Inspect the connections under the airbox. These go to the steering head area. See anything odd?
Pushed out pins, broken wires, corrosion, melting....

 

[chunkygoat]

Cliff nailed it. I'd bet its in the steering area.
Q? Does the engine shut down or just the cluster "reboots".

In addition: I'd do the following:
You might also place the display in Diagnostics mode and do the static TPS read out. You're looking for smooth linear output as you VERY SLOWLY roll the throttle open and closed. Also do like 5 quick snaps to WOT and 5 snaps to FROM WOT to idle. The numbers should repeat exactly. Anyway - I don't see that as the reason your display restarts. They are not likely related.

For the display restart and performance issue:
Disconnect battery
Disconnect ECM - inspect, it unplugs easily
Disconnect cluster - inspect. Anything odd?
Remove both pod covers and inspect all connections by removing them.

IF NOTHING found in either location (Cluster won't help stalling), I'd pull the airbox, you'll need some hearty pliers, a very long 3 mm ball driver allen, and a phillips. Remove the airbox. Inspect the connections under the airbox. These go to the steering head area. See anything odd?
Pushed out pins, broken wires, corrosion, melting....

I suspect the killswitch - the bike wouldn't even start this afternoon. I shot a video but its uploading at a tremendously slow rate. I will try to locate everything you are referring to and check all connections. I was going to bypass the killswitch after work because it seems simple and I'm hoping this will solve it.

The bike doesn't shut off, performance drops tremendously, but the ECU just appears to reboot. At lunch I attempted to ride home from the park, and when I flipped the switch and went to press the starter button, I hear a BZZ and the ECU just shut off. My LED's all get power telling me the battery is fine. The starter when working, kicks on immediately indicating this would be functioning properly.

I had to literally smack the killswitch and the bike fired ride up first try....I suspect this may be it. I will check the airbox and all connections near and around the stearing head area as well. I will also post the video as soon as it is done uploading. Thanks for the advice guys.

Any pictures depicting where the ECU connects, the airbox, would be tremendously helpful -- along with how to place in diagnostic mode and selecting the static TPS read out.

Thanks guys.

 

[chunkygoat]

https://www.youtube.com/watch?v=n7tRPYC6cJ8&feature=youtube_gdata_player

 

[MG-242]

The connectors are the weakest part of any electrical system. Good advice from Cliff and that is a good place to start -at the switch and also the connectors for the instrument panel. I wouldn't suspect the on\off switch. I don't think the gauges reset when you toggle the on\off switch once the instruments boot. In the video it sounded like the engine was smooth while you could observe the instruments booting which would make me think it is not resetting the ECU. It would also be a good time to look at your battery and terminals. Corrosion can cause low voltage and electronics don't like low voltage conditions.

Good luck!

 

[Motogiro]

The connectors are the weakest part of any electrical system. Good advice from Cliff and that is a good place to start -at the switch and also the connectors for the instrument panel. I wouldn't suspect the on\off switch. I don't think the gauges reset when you toggle the on\off switch once the instruments boot. In the video it sounded like the engine was smooth while you could observe the instruments booting which would make me think it is not resetting the ECU. It would also be a good time to look at your battery and terminals. Corrosion can cause low voltage and electronics don't like low voltage conditions.

Good luck!

I agree and in addition:
It could be static/noise from a poor connection. The static might be seen by a a chip that starts clocking but doesn't recognize the signal which causes the reboot.
The other things I was thinking is the instrument cluster seeing an over voltage and shutting off to protect itself. Again this could be caused by intermittent connection that is triggered by the vibration of the engine and if there's enough inductive kick there is a spike high enough to be sensed as higher voltage and thus clamping.
The kill switch is a weak point and a jumper would eliminate it as a source of noise even though it may not be obvious as a DC current failure.

Most definitely check the obvious things as simple as harness plugs and connections at the battery.

 

[chunkygoat]

Thanks you guys.

I checked all connections I could find in the area and everything seemed snug. I bypassed the killswitch after work just to eliminate it as a possibility and everything seemed golden. Low and behold, there was an accident and it was dead stopped traffic for miles and the bike shut off for good this time.

Luckily, I literally just purchased road side assistance and got my card 2 days ago -- which covered my tow to the shop. I couldn't chance having the bike down for days or even weeks while I get to the root of the issue - I am relying on the bike as my commuter while my car undergoes repairs as well!

So the bike is in the shop and luckily my wrencher is waiting on parts for all his current jobs so he can address my issue this morning. He was very confident it was a connection issue and that he would be able to promptly resolve this for me.

I will update the thread when I find what the culprit was.

 

[Motogiro]

Thanks you guys.

I checked all connections I could find in the area and everything seemed snug. I bypassed the killswitch after work just to eliminate it as a possibility and everything seemed golden. Low and behold, there was an accident and it was dead stopped traffic for miles and the bike shut off for good this time.

Luckily, I literally just purchased road side assistance and got my card 2 days ago -- which covered my tow to the shop. I couldn't chance having the bike down for days or even weeks while I get to the root of the issue - I am relying on the bike as my commuter while my car undergoes repairs as well!

So the bike is in the shop and luckily my wrencher is waiting on parts for all his current jobs so he can address my issue this morning. He was very confident it was a connection issue and that he would be able to promptly resolve this for me.

I will update the thread when I find what the culprit was.

Sorry you got stuck out there but good on the added road assist. ins.
Since you mentioned one time you had buzzing sound when you tried to start it. It could be a poor connection near the battery at the main fuse connector assembly located on top of the battery where there is also a starter relay attached. A bad pin in one of the harness plug connectors up front.
Regardless, good luck on your repair ans let us know what it was.

 

[chunkygoat]

Well i got it back - there were two issues, possibly cumulative in nature. The slide cover next to the throttle tube was out of position. I must admit, this may have been a cause of my disassembling the killswitch assembly - but I had not noticed any difference after this change than before.

The grip of the throttle would would snap back to its original position when rolling off, but the misaligned slide cover appears to have been intermtermittenly throwing off the throttle position regardless of where I was physically holding the throttle.

Also, there was a pinched terminal wire from the battery underneath the tank running to the fuse panel. This also may have been my own doing from lifting the tank on a number of occasions. This pinch caused extra tension on the connection to the fuse panel - which is what I am told eventually completely severed, hence the dead bike.

All things I suspect were my own doing, but have no substantial evidence. Also all the repairs were things I could have done myself, if I had the patience and confidence to tow it home rather than to the shop. 130$ and a free tow, all in all I suppose it wasn't too hard of a hit. So the steed is tip top again, and have my new replacement rims on too! (thanks Jeff here on the forum for meeting me!


Thanks for the help guys, lessons learned.

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