Need Help Bike Intermittently Dies or Won't Start

[Veloce]

Hi All,

Long time lurker, first post of my own. I've got an '06 FZ6S, which I've owned for two years. Throughout the time I've had the bike, it's had intermittent problems that I just can't manage to nail down.

Here are the symptoms, although not all of these will happen concurrently:

• While riding with throttle open, the bike will suddenly stutter briefly, and then regain power. It's terrifying when this happens on the freeway at like 80mph.
• When starting the bike, the starter turns but the bike won't start. Error code 19. Switching the key off and back on will allow the bike to start. Often when this happens, it foreshadows the bike dying or hesitating sometime during the subsequent ride.
• When coming to a stop, the bike dies. Dash is still on. Again, switching the key off and on will let me start it after this happens.
• Recently while riding with the throttle open, the bike lost power, like the engine just cut off. I twisted the throttle a couple of times and it kept the engine running, however it hesitated quite a bit as I gave it throttle, like it was down a cylinder or two. I was able to pull off into a parking lot. No codes on the dash. I parked, turned the bike off, back on, and everything seemed normal for the rest of the ride home.

All of these occurrences are seemingly random, and I can often go months at a time without any symptoms at all.

Here's what I've done so far to troubleshoot:

• With the engine running and the tank up slightly, I've wiggled every damn wire and connector I can see, especially those on the starter safety cut-off circuit: the battery cables, the starter relay connections, the ignition wires (and jiggled the key in the ignition), the kill switch wires, the ECU harness wires, the side stand switch, the tip-over switch, the fuel pump connectors and wires, the clutch switch, the neutral switch, the cutoff relay harness.
• Disassembled and thoroughly cleaned the side stand switch. Cleaned the connector with contact cleaner.
• Replaced the kill switch with a brand new one. I don't use it. Just wanted to firmly eliminate this as a culprit. (Plus, you need the kill switch to reset codes, so didn't want to jump it.)
• Replaced the Starter Circuit Cutoff Relay with a brand new one.
• Installed new Iridium spark plugs. Confirmed the plug caps are tight and are firmly screwed onto the wires.
• Checked vacuum, breather, and fuel hoses for kinks or damage.
• Checked the TPS numbers, 16-100, no gaps.
• Checked connection of main harness to ECU. Clean and tight.
• Treated fuel with Yamaha Ring Free Plus.

I've looked through old posts about similar symptoms, and almost all of them point to the kill switch or starter circuit cutoff relay, both of which I've recently replaced with brand new OEM parts. It's been quite frustrating trying to find this gremlin, and for all I know it's not just one. I do own a multimeter and test lamp, however my electronics chops are super basic so I'm not sure what to test. Also, is it possible that this is fuel related? This is the first bike I've actually worked on myself, so I'm fairly green when it comes to troubleshooting. Any help from the community here would be greatly appreciated!

 

[Motogiro]

I forget where it's located but I believe it's uned one of the pods below the seat. Check that your lean angle switch is securely plugged in and the unit is secured to it's mounting.

#19 is a sidestand error code. Check switch and wiring.

 

[TownsendsFJR1300]

I forget where it's located but I believe it's unded one of the pods below the seat. Check that your lean angle switch is securely plugged in and the unit is secured to it's mounting.

#19 is a sidestand error code. Check switch and wiring.

It's under the right side pod...

Kinda sounds like the ignition switch misbehaving.

 

[Veloce]

I forget where it's located but I believe it's uned one of the pods below the seat. Check that your lean angle switch is securely plugged in and the unit is secured to it's mounting.

#19 is a sidestand error code. Check switch and wiring.

Lean angle switch is secure and tightly plugged in. I've thoroughly cleaned the side stand switch and ensured the plug is clean and secure.

 

[Veloce]

It's under the right side pod...

Kinda sounds like the ignition switch misbehaving.

Is there any way to test this?

 

[Motogiro]

Is there any way to test this?

Intermittent problems are tricky to diagnose. When this happens while You're riding and the engine stops, do you still see an active instrument cluster? If so, i believe you stated it will crank, but it won't start unless you cycle the key off and then on again. This makes me think the ECU sees something it doesn't like and it holds the default shut down of fuel state until powered off and then on again. It seems there's a sidestand code 19. It might get triggered and kill the motor.
You might try eliminated the side stand trigger by disconnection the neutral safety wire and attach it to ground. If this is triggered by an intermittent sidestand fault the ECU will not shut down the engine because it thinks the transmission is in neutral all time time. Just be careful because at this point the neutral safety protocols have been eliminated. This may prove out the intermittent sidestand fault which will let you focus on the source.

 

[Veloce]

When this happens while You're riding and the engine stops, do you still see an active instrument cluster?

Yes. The cluster stays lit and active.

If so, i believe you stated it will crank, but it won't start unless you cycle the key off and then on again.

If it happens while I'm in motion, typically the engine will hesitate, but then regain power without me doing anything. The last time this occurred, the engine bogged down more than usual, and I immediately pulled over and shut the bike off. When I switched it back on, it came right back up, but there were absolutely no codes in the diagnostics. I can't state with certainty, but I believe code 19 has only come on when I've been trying to start the bike and it cranks but doesn't start.

 

[Gary in NJ]

Can you connect a voltmeter/multimeter to the bike and check the charging output while you are experiencing the condition?

 

[Veloce]

Can you connect a voltmeter/multimeter to the bike and check the charging output while you are experiencing the condition?

I can try. Of course the bike is behaving perfectly now. Ha.

 

[Veloce]

Can you connect a voltmeter/multimeter to the bike and check the charging output while you are experiencing the condition?

@Gary in NJ: I bought a little eBay volt meter that I intend to wire up semi-permanently. What do you recommend I connect the leads to? Should it go on the same circuit as the safety cutoff components? I’m not sure if that circuit is switched.

If it just needs power from the battery, I could just wire it into a switched fusebox I have under the seat.

 

[Motogiro]

@Gary in NJ: I bought a little eBay volt meter that I intend to wire up semi-permanently. What do you recommend I connect the leads to? Should it go on the same circuit as the safety cutoff components? I’m not sure if that circuit is switched.

If it just needs power from the battery, I could just wire it into a switched fusebox I have under the seat.

You should be good getting your 12 positive off one of the switched, fused circuits and your negative from the negative battery terminal. Just be sure you have secure safe connections. Keep in mind that although it may be a digital volt meter DVM. You could have different than suggested/specified voltages but within a half volt you should be close.
I still think it would be a good idea to ground the neutral light wire. To see if the problem subsides.

 

[Shodan]

@Veloce Did you figure this out? I'm having the same issue. Randomly, my FZ6 would show error code 19, check engine light, and in that state if I crank it - it won't start. The issue typically goes away upon turning it off and back on.

I don't think this is a kickstand sensor issue at all, because:
1) this happens in neutral - in which case the bike should start regardless of what the kickstand sensor is reporting. The neutral sensor is working fine - the 'N' always lights up when the bike's in neutral, and it's on when this issue happens, as well.
2) if I drop the kickstand when the bike is in gear and running - it shuts off alright, but without the error 19 code
3) if the kickstand IS in fact down, and the bike is NOT in neutral - it won't even crank. But with this code it does crank.
So it must be something else. Not sure why anyone said it's the kickstand sensor.

I've taken out the ECU, looked at the harness connector - looks clean. Plugged it back in.
Also I've had the random engine shutoff issue in the last couple months: once while riding, complete loss of power for about 4 seconds, then resumed pulling as usual. And 2 other times the engine died within a few seconds after starting, while idling.

The fact that it shows up when I turn on the bike for the 1-st time but not subsequent times - makes me think it cannot be a loose wire - powering things on wouldn't cause a loose wire to reconnect without any physical impact to the bike or wiggling anything at all.

At this point I'm thinking it's that the ECU is crapping out...

Bike's an '09 FZ6 btw. I believe it's the FZ6-S2, although the '-S2' seems to be optional. And I've never heard of an FZ6-S1...

 

[Veloce]

@Veloce Did you figure this out?

Unfortunately, no… I mean, it hasn’t happened since the last time (when I posted about it). Anecdotally, I’ve noticed that for me it seems to happen after I’ve been working on the bike with the tank propped up. I suspect it may have to do with the wires to the fuel pump, but that’s mostly just a hunch. I haven’t been under the tank in a while, and I (thankfully) haven’t had the issue since.

 

[Motogiro]

@Shodan
Series 1 (S1) are the FZ6 manufactured from 2004 to 2006 Series 2 (S2) are 2007 to 2009.

Besides other electrical interruptions including the kill switch and ignition switch, anything related to the bike cutting out and not allowing the starter circuit to engage could be related to logic that occurs with the neutral safety, sidestand switch, and clutch lever switch. These are all connected to the Starter interrupt- cut off relay assembly. This is an assembly that has a diode logic circuit and 2 small, on board relays. The 2 relays control the starter relay that allows current going to the starter and the fuel injection circuit.
Besides an internal intermittent issue within that assembly you might check the connection at the 16 pin plug to insure the connection is clean and secured.
I believe that module is in the left side pod next to the headlight relay.