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Missfire under load

wayneborn1976

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Hi all, i recently just started having a problems with my fz6, i hadnt ridden the bike in approx 3 weeks, all was well when i rode it last, i jumped on the bike to go to work the other day and it missfires, it feels like it is running on 3 cylinders, i changed the plugs and checked the leads for spark all is good there. i put a fuel/injector cleaner in the tank also thinking it may be a bad batch of fuel, after doing all these fixings, it still runs like crap but not all the time, it will cut in and out depending on how much throttle i roll on. i'm stuck... any ideas what the problem could be?
cheers
wayne
 
A bad throttle position sensor could cause the problem you're describing but I don't think the 2006 models were part of the recall. Not to say that would mean your TPS is not suspect.

If you have good spark, have you checked your fuel and air? Is the air filter ok, and is the fuel system working (pump/injectors).

Ethanol is nasty stuff, and 3 weeks of sitting could allow water to enter the fuel system. You might try to drain off some of the fuel into a small clear container to see if you have water contamination.

Here is the TPS check from the service manual:
tps.jpg
 
Thanks Shamus, i will drain a bit of the tank out to see if that has anything to do with it, the only other thing i thought was a gummed up or blocked injector, i will check the TPS and make sure that is ok, if all ok, the next step would be pull the injectors off and make sure they are ok.
cheers for that, it will give me somewhere else to start looking.
 
Ethanol does complicate things, but 3 weeks is no problem to sit with this bike fuel-wise. We all run E10 here in MA. It does help if it is going to sit that the tank is filled all the way up to avoid moisture buildup.

The TPS is a good thing to test. Taking a step back, did you check your battery voltage (bike off, and bike running)? How old is it?
 
It had a full tank of fuel when it was stored, i filled the tank on the way home from work then it was parked for 3 weeks, it would only have done no more than 40km when the problem started, thats what made me think it may be a fuel issue.
The battery voltage is fine, i replaced the battery 12 months ago. i drained the tank a little last night into a container and no water came out, it was a little dirty though, i have an additive n the tank at the moment to clean the injectors, so i will wait till this tank is nearly finished and i will pull the tank off and clean it and also check the TPS
thanks guys.
 
That little bit of dirt that came out of the the gas tank is a big tell tale of your problem.


I'd siphon most of the fuel out of the tank, then remove the tank.

I'd flip the tank over a bucket and catch what comes out. If there's water/rust, you'll see it. Flush it with some fuel (approx .25 gallons at a time) until what comes out is clean. An air compressor helps blow any crap out as well..

The longer you run it with crap in there, the harder it'll be to get the system clean...

Once re-assembled, some fresh gas and fuel stabilizer. Chevron techtron makes a very good fuel system cleaner (available at Walmart/automotive stores). Marinas sell fuel WITHOUT ethenol in it if you want to go that route.

I just did a VT1100 gas tank (and carbs cleaned-varnished up idle curcuit jets) and had to flush the tank several times before everything was out and the bike was running as new again.
 
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yeah you were right townsend, i pulled the tank off and cleaned it out, flushed and put an air hose in to clean out, filled it with fresh fuel and it runs like a dream, i also pulled the injectors off and gave them an ultrasonic bath to make sure, so thanks heaps guys.
 
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