2000 Yamaha ox66 in emergeny or limp mode

[competitioncoatings]

Engine revs to around 2000 the goes up and down. No warnings or buzzers. Changed stator, oil level switches, vst tank, checked harness running out of options, any help???

 

[rodbolt]

Re: 2000 Yamaha ox66 in emergeny or limp mode

have you tested the buzzer to see if it works? what visual indicates are on the tach?

 

[competitioncoatings]

Re: 2000 Yamaha ox66 in emergeny or limp mode

Yes, Buzzers work fine, Tach is reading engine rpms fine. Have duals engines switched most of the parts over but no luck

 

[rodbolt]

Re: 2000 Yamaha ox66 in emergeny or limp mode

can we get a model number so we can see which system we are dealing with?

 

[competitioncoatings]

Re: 2000 Yamaha ox66 in emergeny or limp mode

I will get it in the am. Thanks in advance for your help.

 

[competitioncoatings]

Re: 2000 Yamaha ox66 in emergeny or limp mode

Heres what on the tag LX250TXRY

61 X 102651

 

[rodbolt]

Re: 2000 Yamaha ox66 in emergeny or limp mode

that engine incorperates a CCS system. means from about 750 RPM to about 1200 RPM it drops a cylinder,from about 1200 RPM to about 1800 RPM it drops 2 cylinders,at about 1800 to 2000 RPM and up it runs on 6.
sometimes especially in nuetral, it scales if you try to hold that RPM.

 

[competitioncoatings]

Re: 2000 Yamaha ox66 in emergeny or limp mode

Runs great if I disconnect yellow wire on ecm. But still cannot get it to run right. Have someone bringing a flasher tomorrow, just maybe we will figure it out.

 

[competitioncoatings]

Re: 2000 Yamaha ox66 in emergeny or limp mode

Also the other engine does not do it or have that problem.

 

[rodbolt]

Re: 2000 Yamaha ox66 in emergeny or limp mode

might run in bypass mode,maybe better than in broke mode.
but it cant run great.
in bypass mode fuel is fixed rich,timing is fixed,most ECU functions quit.
remember with the diagnostic test lamp installed there is NO automatic oil transfer.
also it will ONLY display a code WHEN the code is active.that system wont store codes.

 

[competitioncoatings]

Re: 2000 Yamaha ox66 in emergeny or limp mode

Put the diagonstic flasher on it, checks out ok. This thing has everyone around here stumped???

 

[99yam40]

Re: 2000 Yamaha ox66 in emergeny or limp mode

Yes, Buzzers work fine, Tach is reading engine rpms fine. Have duals engines switched most of the parts over but no luck

The question was refuring to is there any indicators of oil or heat problems on the tack when problem occurs .
Is this problem happening in gear or in neutral?

 

[competitioncoatings]

Re: 2000 Yamaha ox66 in emergeny or limp mode

No buzzer or alarms. Gauges are working fine. No heating or oiling problems. Happens in neutral and in gear.

 

[rodbolt]

Re: 2000 Yamaha ox66 in emergeny or limp mode

what the fuel rail presure at the problem RPM,whats the CDI output voltage at the problem RPM.
will the engine smooth out above 2400 RPM and remain ok to about 5300 rpm.
have the fuel pumps been checked, have injector screens ben checked has the O2 sensor output voltage been checked.

 

[competitioncoatings]

Re: 2000 Yamaha ox66 in emergeny or limp mode

Switched stator, vsp tank, and timing sensor to other engine. Now problem has moved to good engine. Is it safe to say its one of those things? Would trim switch on control have any interference with this problem??

 

[rodbolt]

Re: 2000 Yamaha ox66 in emergeny or limp mode

dunno
I am a trained technician not a parts changer.
I tend to trouble shoot things until the issue is resolved.
as one of about 70 Yamaha Master techs in the US I tend not to swap parts or poke-n-hope.
check rail pressure,TPS voltage and CDI output at the problem RPM and load, you will solve your issue most likly.
kinda what I said before