FZ6S 2006 throttle problem

[galvic]

Hi, everyone, if anyone has knowledge, please help. I have bought fz6 s from 2006 sone 11 months ago, and after few months it would, after some wormup start to sputter and shake badly when throttle is twisted a little more. Under light twisting of the throttle, everything was OK, as well as when cold. The problem would stop by itself after few tens of km, or the next day. It would occur every month or so once, and as I can tell after a day or two of non riding, usualy if it was ridden every day, all was OK for some time. In past two weeks the problem aggravated, and again after wormup (10 min of riding) it would start again, now with poor idle too (sounds like two cylinder engine). I checked coild, plug caps and replaced sparkplugs (CR9EK), but all that's changed is a little more throttle can be twisted before shake. Ah, yes, on idle it would run like 2 cyl mixed with almost normal sound intermittently. No err or fault code has been displayed on the screen, except that fuel pump will not cut out when it reaches 2,5 bar fuel pressure on startup, and if you do not start motor immediately engine orange diode is lit, but if you do start it at once, the light does not come. Thank You in advance for any input, Niksa.

 

[Cloggy]

Hi, everyone, if anyone has knowledge, please help. I have bought fz6 s from 2006 sone 11 months ago, and after few months it would, after some wormup start to sputter and shake badly when throttle is twisted a little more. Under light twisting of the throttle, everything was OK, as well as when cold. The problem would stop by itself after few tens of km, or the next day. It would occur every month or so once, and as I can tell after a day or two of non riding, usualy if it was ridden every day, all was OK for some time. In past two weeks the problem aggravated, and again after wormup (10 min of riding) it would start again, now with poor idle too (sounds like two cylinder engine). I checked coild, plug caps and replaced sparkplugs (CR9EK), but all that's changed is a little more throttle can be twisted before shake. Ah, yes, on idle it would run like 2 cyl mixed with almost normal sound intermittently. No err or fault code has been displayed on the screen, except that fuel pump will not cut out when it reaches 2,5 bar fuel pressure on startup, and if you do not start motor immediately engine orange diode is lit, but if you do start it at once, the light does not come. Thank You in advance for any input, Niksa.

Hi Galvic a big :welcome: to the forum.

Has the dealer carried out the TPS fix? There was a recall on several early FZ6 bikes, Here's the thread explaining it and what problems it can cause:

throttle position sensor issues-are you experiencing poor idle mileage stalls

Here's the document:
Yamaha FZ6 TPS Replacement

 

[galvic]

Thank You, Cloggy for the response, I will check the diag later, however, here in Croatia, I do not think that recall for 2006. model will work.

Hi Galvic a big :welcome: to the forum.

Has the dealer carried out the TPI fix? There was a recall on several early FZ6 bikes, Here's the thread explaining it and what problems it can cause:

throttle position sensor issues-are you experiencing poor idle mileage stalls

 

[dschult2]

^ +1 on the TPS and welcome to the forum.

 

[FinalImpact]

Any chance the fuel has water in it? Find the best product available there for removing water from fuel and mix at ratio proper for fuel tank/volume.

Can you try to explain this again?
>> except that fuel pump will not cut out when it reaches 2,5 bar fuel pressure on startup, and if you do not start motor immediately engine orange diode is lit, but if you do start it at once, the light does not come.


Does this mean you tested the fuel pressure and it holds 2.5bar? It sounds like you are saying it GOES HIGHER to say 2.8 or MORE? Is this true? How high does it go?

 

[galvic]

About the pump, You know when You turn the key to on position, You can hear the fuel pump whnning for two ot three sec, and then it stops (presumably when it reaches op. pressure in fuel line). Well, mine does not cut out, but continues to work. I did not test the fuel line, however, on the pump assembly there is return valve (one way) in the tank, and maybe there is something jammed in it seal, or the spring just don't hold anymore, I will have to take the pump out. I tested the diag. mode, and for tps, it goes from 16-101, which is within specs. Thanks for Your help.
Any chance the fuel has water in it? Find the best product available there for removing water from fuel and mix at ratio proper for fuel tank/volume.

Can you try to explain this again?
>> except that fuel pump will not cut out when it reaches 2,5 bar fuel pressure on startup, and if you do not start motor immediately engine orange diode is lit, but if you do start it at once, the light does not come.


Does this mean you tested the fuel pressure and it holds 2.5bar? It sounds like you are saying it GOES HIGHER to say 2.8 or MORE? Is this true? How high does it go?

 

[FinalImpact]

I have no proof either way but what i do know is there is no pressure sensor conveying information to the ecu from the fuel pump.
That leaves two options: time and load sense.

Time: upon key on, the ecu enables power to the fuel pump for lets say 4 seconds. If it does NOT detect engine rotation from the CPS (crank sensor), it turns off power to the pump. If you push start the bike, the cps moves and the ecu turns on the pump for a period of time (looking for running engine cps signal).

Load: there is a very good possibility the fuel pump uses both TIME and load detection. That is, a pump under load draws more current as it builds pressure. The ecu could detect this and coupled with the TIME function, could time out/turn off when both load was high for a period of time and the time runs out before detecting CPS movement.

How does this effect you? You said the pump runs long. I bet your fuel system is either full of rust and can not pick up fuel or the internal pressure relief valve is stuck open from a small piece of debris stuck in it.

There are several threads here about pressure testing. I would do that as my next step because your pump should turn off.

search JJD952 pump pressure fuel
Etc and see what you get