Weird Electrical problem

[wurk_truk]

OK.  Bike tore down for engine rebuild so cannot play with it presently.

But here's the deal:

I can turn "off" the run/stop switch and the bike will stay running, but very crappy.  Misses, etc.   I took fist and slapped handlebars on top of switch, and DBW quit working.  I was on the road so you can believe THAT flipped me out.

Beat on bars and throttle again.  From that point onwards, I used the ignition switch to turn the bike on and off.

Bad run/stop?   If the ECM get partial voltage can it still run like crap, or go into 'limp'?  Is the run/stop an actual switch to something, or is it a 'signal' to the ECM?

WTF???

While bike is all apart, I think the run/stop switch has to be swapped out.  This couldn't be a tuner issue could it?

[FLTRI]

This couldn't be a tuner issue could it?

Simple answer: No

[HarleyFranco]

The run/stop switch is just that, a switch, it will either be good or bad.  It's easy to test with a digital voltmeter.  Now the wiring for the circuit is another matter, you might have a bad ground or a loose connection someplace.  Use the wiring diagram to find how the circuit runs and where it's connection points are and start there.

Frank

[FLTRI]

The run/stop switch is just that, a switch, it will either be good or bad.  It's easy to test with a digital voltmeter.  Now the wiring for the circuit is another matter, you might have a bad ground or a loose connection someplace.  Use the wiring diagram to find how the circuit runs and where it's connection points are and start there.

Frank

[nc-renegade]

The run/stop switch is just that, a switch, it will either be good or bad.  It's easy to test with a digital voltmeter.  Now the wiring for the circuit is another matter, you might have a bad ground or a loose connection someplace.  Use the wiring diagram to find how the circuit runs and where it's connection points are and start there.

Frank

Your description points to a bad run/start switch or wire to this switch.  The switch could have internal corrosion and have a high impedance, which clears up when banging the handlebars.  A digital ohmmeter should be able to rule that out too.  Older bikes had the 12V supply to the coil running through this switch and a high impedance would do exactly what you described.  A quick look at 05 schemetic (CARB model) shows the switch supplying the center connection as well.  It is more complex with EFI, goes to the system relay coil, which then supplies through it's contacts the power to the coil.  I don't have a 08 or 09 manual, so I don't know if the same system relay also controls the DBW circuit...imagine it does though, indirectly through the EFU.

I would check the switch and the wire/connectors in the handlebar.  A wire might be pinched at the hand controls.

There is debate whether to use the start/run switch or the ignition switch.   Folks have reported the run/start switch going bad over time.  I always used the ignition switch and have not had a problem.

[FLTRI]

I always used the ignition switch and have not had a problem.

[wurk_truk]

2009 SG, 20k on bike.  Dirt Bike HABIT for me to use the run/stop switch.

I know that on DBW... using run/stop can screw with idle... so says Steve Cole.

It the "keeps on running but turns off the DBW" thing, that I wanted to report to you guys....  such an odd occurrence.

Im gonna look in SM.

[FLTRI]

..."keeps on running but turns off the DBW" thing....

Not sure I understand what you are saying.

[HarleyFranco]

work_truk,

Are you saying that the bike keeps running but the throttle is not active?  Bike will idle only?

Frank

[wurk_truk]

Yes.  Bike will idle and throttle will not work.  I was 800 miles from home.

This is why I think the run/stop is no more than a 'signal' to the ECM.  PLCs and ECMs and such have threshold voltages because of the transistor like qualities inside of them.  When one gets right about threshold... weird things happen, like this!!!

So, I think the switch is defective and 'leaks' voltage when in the off position, or there is a short across the leads somewhere that leaks a few volts constantly.   I sure hope that it is not the DBW!  But it works fine as long as I don't touch the damn switch.

The idle quality is very poor when this happens, too.

Weird!!!

OK.  I looked in the SM.  The ignition switch turns on power.  This feeds the run/stop with gray wire.   The run/stop output is white with black and feeds power to the starter switch, and also is a direct input into the ECM, I think pin 27.  It goes nowhere else.   I have a megger and I will ohm out the switch in the off position just for fun.

[Don D]

You sound electrically sauvy if you can borrow or have a good meter, such as a Fluke, this condition you describe will show
Just for the heck of it have you run the speedo code check? Also check your grounds.

[wurk_truk]

I forgot to pull the speedo codes before I tore it down.  I will do so when I put it back together.

I have all kinds of meters.  I was thinking of the megger, as that's the meter we use to test the insulation on motor windings.  Of course... this is INVASIVE testing and if switch is bad before... it will really be bad when I get done with it!

HAHA!

Also, though, if the switch can withstand this... the problem really is elsewhere (like wire harness or fairing plug).   I wish I understood engines like I do electrical...

[blkfalc4]

Just make sure you pull the ECM connector before juicing it with 500vdc....hehe

[Ram]

If your going to use the megger, I would only use it on segments of wiring that have both ends disconnected.  Like all the harness lying on the bench.  That whey if you did have leakage it would not effect other wiring which is still physically connected to something inadvertently, like your radio, the ECU, the TSSM etc! 

A megger is kind of extreme for testing the bike wiring. The same for the most part can be done with a Fluke and a fox and hound.

[rigidthumper]

And there is always the possibility that the W/B wire is shorted to the O/W or G wire under the mastercylinder clamp (things get pinched there a lot),  bypassing the run/stop switch.
HTH
Robin

[wurk_truk]

And there is always the possibility that the W/B wire is shorted to the O/W or G wire under the mastercylinder clamp (things get pinched there a lot),  bypassing the run/stop switch.
HTH
Robin

I thought of that a few posts ago.   If pinched... it would do the same thing, EXCEPT.....WTF beating on the handgrip changed the operation   Then beat the grip again and it went back.

Pretty sure its the switch.  I think I can hit that switch with 250!  HAHA,   Seriously, though...  I will ohm out the whole damn thing one wire and wire set at a time.  I just have NO faith in HD techs when it comes to wiring.  Hell, half can't read the factory schematic.