Stalling and Surging

[MooseJuice71]

Hello,

I have a 2008 FZ6, only 6k miles, but sat in the original owners garage for a year without use before I bought it. I am having a problem with the bike both stalling and surging. The stalling happens in the middle of rides when I let off the throttle. For example, I will go to shift and notice the bike is off and at 0 RPMs and have to pop start it. It also stalls sometimes at a stop when I rev it in neutral. After I rev it, the RPM needle just drops straight to 0.

The bike also surges when constant throttle is applied. This usually happens after the bike has been warmed up for 2-3 minutes. For example, if I hold constant throttle, it surges about 300 RPMs higher than the constant RPM I am holding. This happens while moving and in gear at a rate of about 2 times/second.

Can anybody help me? What could be causing this?

Thanks,

John

 

[tejkowskit]

Some owners have had problems with the throttle position sensor, though I thought Yamaha worked this out by 2006. Go through the TPS diagnosis just for somewhere to start. Read this and see if it helps. http://www.600riders.com/forum/fz6-technical/181-throttle-position-sensor-issues-you-experiencing-poor-idle-mileage-stalls.html
Hope it helps.

 

[bd43]

It sounds like an air/fuel issue and not electrical.

1. How fresh is the fuel? Did you put in fresh fuel when you got it or are you trying to run the fuel that was in the tank from a year ago?

2. How does it idle and at what RPM is that? Does it idle smoothly or seems rough like it's missing? The RPM should be around 1200 at idle but I wouldn't re-adjust idle until I did a couple of checks.

Check the following:

Air filter, is it clogged or has some rodent moved in and made a nice little nest in the air box? Take the top off the air box and look inside to inspect.

The fuel tank has a vent hose so check to see if it is kinked under the tank. If the hose is kinked or clogged then the tank will become a vacuum or restricted, starving the engine of fuel. If the idle is rough, try idling with the tank cap open to see if that smooths it out.

Your bike is an 08 so I'd be very surprised that your TPS is shot but it could happen.

If you can comment on 1 and 2 and report back on your findings on the items to check, we can go from there.

Cheers.

 

[Kaisersoze]

Throw in injector cleaner and run 93 octane. Sounds like clogged injector if it was just sitting in garage. Maybe try some seafoam.

 

[04fizzer]

Throw in injector cleaner and run 93 octane. Sounds like clogged injector if it was just sitting in garage. Maybe try some seafoam.

I strongly second the Seafoam. Run the recommended amount for cleaning (roughly double what is used to maintain), then change your plugs after a couple tank fulls.

 

[MooseJuice71]

It sounds like an air/fuel issue and not electrical.

1. How fresh is the fuel? Did you put in fresh fuel when you got it or are you trying to run the fuel that was in the tank from a year ago?

2. How does it idle and at what RPM is that? Does it idle smoothly or seems rough like it's missing? The RPM should be around 1200 at idle but I wouldn't re-adjust idle until I did a couple of checks.

If you can comment on 1 and 2 and report back on your findings on the items to check, we can go from there.

All, Thank you for the very helpful responses. I will go pick up some seafoam tomorrow.

To answer these questions:

1. I have actually put 3k miles since I bought it in June. I had originally thought it might be bad gas as well, but I have cycled through many tanks of gas, so I do not believe this is the problem.

2. The idle is a bit rough, the idle is set at about 1250 RPM warm, but the needle will fluctuate between ~1100 and 1400 (Not sure if this is normal or not).

I also did the TPS check and that is fine. I would like to check the air filter but not sure how to do it. The tank is almost empty in anticipation of doing this, do I need to pinch any hoses to avoid gas leaks when I check this?

Thanks again for all the help, I really appreciate it! :thumbup:

 

[bd43]

All, Thank you for the very helpful responses.
2. The idle is a bit rough, the idle is set at about 1250 RPM warm, but the needle will fluctuate between ~1100 and 1400 (Not sure if this is normal or not).

No, not normal. Idle should not bounce around like that.

[ame=http://www.youtube.com/watch?v=r6qRAJgAzfY]FZ6 at idle - YouTube[/ame]

A quick check to see if your vent line is causing the rough idle is to idle with the tank cap open. Did you try that to see if the idle smoothed out?

 

[FinalImpact]

If the TPS checked out OK - I'd be pulling the connectors apart on the ECM, TPS, Air sensor, etc and verifying the grounds, battery and fuses - Remove and re-insert them. It just seems like you have an intermittent connection.

Hopefully the rodent penetration is negative and there are no chewed wires etc.

With the seat and tank and maybe the lower section of the air box do a thorough inspection looking for corrorsion within the connectors you pull apart.

Good luck.

 

[MooseJuice71]

I just checked out the vent lines and air box... One of the vent lines has a crease in it, indicating that it may have been kinked. The air box was clean, but the filter was a bit dirty so i put a new K&N air filter in. I bolted everything back up and made sure none of the lines were kinked. I also filled it up with a fresh tank of premium and Seafoam.

I am going to take it for a hard ride now and I will report back. Thanks for the help so far, lets hope this works!

 

[TownsendsFJR1300]

If the Seafoam and your other checks don't pan out, I found a product that works very, very well cleaning injectors and picking up any moisure in the fuel tank allowing it to burn off. I've used it in my boat and can personally say that it does in fact work. Kinda expensive, but works really well (I use Seafoam as well). I've used it in very small engines(weedeaters, etc) for carbs (with extremly small orifices) that don't respond to carb cleanings. It helps and IMHO, works better than Seafoam or Tectron (I use both regularly).

K100 Fuel Treatment : Fuel Additive, Fuel Saver (K100MG)

My local shop has a display of different additives mixed with water and gasoline. This product was THE ONLY ONE to stay mixed and NOT SEPARATE. You could not see the water settle unlike the other products...

A throttle sync would hurt either, if it hasn't been checked, its due...


Good luck

 

[ChevyFazer]

Check you battery, wires, coroision, voltage if you have a bad connection or bad battery it will act the same way

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