pcv

[bhick]

I just got a Dyna Jet Power Commander V from Fuel Moto and installed it,but in the installation instructions it states (It is recommended to disconnect the stock o2 sensor to get the full potental out of the bike and the pc.) My question is if the o2 sensor is disconnected will the ecu put out a o2 falt code?

 

[FJRay]

All I can add is that on mine the sensor is still connected and it works just fine. I'm sure some of the others will chime in with opinions that are worth just as much as mine. I will say that if you want full potential fronm the PC it needs to be tuned on a dyno by somebody that knows what they are doing and even then as soon as conditions change so does the tuning.

 

[bhick]

All I can add is that on mine the sensor is still connected and it works just fine. I'm sure some of the others will chime in with opinions that are worth just as much as mine. I will say that if you want full potential fronm the PC it needs to be tuned on a dyno by somebody that knows what they are doing and even then as soon as conditions change so does the tuning.

Thanks for the reply. I put it on to help with the low speed surge so I think I will leave it connected as you did, this bike is to fast (or maybe Im to old to need more power).

 

[ahchiu]

I just got a Dyna Jet Power Commander V from Fuel Moto and installed it,but in the installation instructions it states (It is recommended to disconnect the stock o2 sensor to get the full potental out of the bike and the pc.) My question is if the o2 sensor is disconnected will the ecu put out a o2 falt code?

No It won't all you have to do is unplug the O2 sensor or replace the O2 sensor with the plug supplied. did you get the Autotune?

 

[Fred W]

I also bought a PC (in my case it is a III) specifically to alleviate low throttle surging.

I tried valiantly to keep my O2 connected. But the surging continued as long as the O2 is hooked up. What seems to happen is that the O2 sensor actually is able to over-ride the input from the PC and puts the mixture back to lean. And the surging continues.

So I've had to go back to disconnecting the sensor and everything is as smooth as silk. I've come to realize that, either not all FJRs surge, or not all FJR riders are sensitive to the surging. Unfortunately, mine does, and I am.

No fault codes will be thrown when you unplug the O2 sensor. The ECU just stays on open loop mode, which is what you want. Easy enough to try it both ways and see which feeling you prefer.

 

[SkooterG]

You are *supposed* to disconnect the O2 sensor. For the most part there will be no codes.

I ran my first 04 FJR for 220,000 miles with a PCIII and the O2 sensor disconnected.

 

[Redfish Hunter]

We bought our PC-V from Fuelmoto and I got confused because I got two different answers from them on this subject. Out of fear, I left the O2 sensor connected, the bike runs great. Fuelmoto assures me that it will run better with it disconnected and I believe them but it runs better now than it ever did so I am scared to fool with it. I will probably give this a shot soon but like I said it runs great now, I can't imagine anything better.

 

[bhick]

We bought our PC-V from Fuelmoto and I got confused because I got two different answers from them on this subject. Out of fear, I left the O2 sensor connected, the bike runs great. Fuelmoto assures me that it will run better with it disconnected and I believe them but it runs better now than it ever did so I am scared to fool with it. I will probably give this a shot soon but like I said it runs great now, I can't imagine anything better.

I only got the pcv no auto tune. It just makes sense to me that the o2 sensor would signal the ecu with a signal sense the pcv is controling the fuel, I think I'll run for awhile connected then disconnect it and see which is best. Then put the 02 settings back to factory instead of the +5 that Ive been running atand see where that takes me. Thanks all for the input

 

[Redfish Hunter]

FWIW the man a Fuelmoto assured me that with the O2 connected the ECU would attempt to bring the stoichiometric ratio back to factory settings. He said that this would be a lean condition and that throttle response would improve with it disconnected. In our case power was not an issue, the jerky off/on throttle response and low end surging were killing us. Power is the same as before but the issues we had were corrected. Fuel mileaged seems to be slightly improved. Unfortunately Dad has been busy on the coast running speckled trout trips so the bike has been collecting dust, I have no recent rides to compare.

 

[bhick]

FWIW the man a Fuelmoto assured me that with the O2 connected the ECU would attempt to bring the stoichiometric ratio back to factory settings. He said that this would be a lean condition and that throttle response would improve with it disconnected. In our case power was not an issue, the jerky off/on throttle response and low end surging were killing us. Power is the same as before but the issues we had were corrected. Fuel mileaged seems to be slightly improved. Unfortunately Dad has been busy on the coast running speckled trout trips so the bike has been collecting dust, I have no recent rides to compare.

Well i took the bike out for a short trip (50miles)freeway and back road. The pcv is really nice ,feels like a new bike. I used 1.15 gal. so 43mpg which i will take anytime,heading out for a day trip in the morning over the cascade loop so i can really check it out. I did notice on the first ride the avg. fuel useage went up to 47 the highest I have ever seen so I know that is off but with the surge and jerkyness gone and 40+ mpg I can live with the incorrect avg mph reading.

 

[Redfish Hunter]

Yes the indicated MPG on the dash becomes uselessly optimistic once you install the PC-V. And to repeat myself, I am sure that SkooterG is correct (as usual) and the O2 sensor is supposed to be disconnected. The only reason we did not was because of confusion/miscommunication at the beginning and fear/laziness now.

 

[bhick]

Yes the indicated MPG on the dash becomes uselessly optimistic once you install the PC-V. And to repeat myself, I am sure that SkooterG is correct (as usual) and the O2 sensor is supposed to be disconnected. The only reason we did not was because of confusion/miscommunication at the beginning and fear/laziness now.

Well after yesterdays 400 mile ride I'm sold on this pcv. Its got tobe the best $300. I've spent on an upgrade so next time I have the tank off I'll pull the o2 connection and see what that does. Its kind of upsetting to me that yamaha let this problem out the door. This is my 4th yamaha and I'm sold on their bikes, it had tobe a money or epa thing. Well at least its corrected now.

 

[Fred W]

Yes the indicated MPG on the dash becomes uselessly optimistic once you install the PC-V. And to repeat myself, I am sure that SkooterG is correct (as usual) and the O2 sensor is supposed to be disconnected. The only reason we did not was because of confusion/miscommunication at the beginning and fear/laziness now.

Nothing to fear here. Unplug the O2 and see if you like it. Run the exact same map. It should get even smoother at the bottom. If you decide that you don't like it, just plug the O2 back in and you are back to how it is now.

As an aside, DynoJet clearly intended the PCV to be run without the stock O2 sensor. They would really like you to buy the AutoTune with the wideband O2 sensor that screws into the bung the stock one is in now. Then you truly do get the best of both worlds.

Well after yesterdays 400 mile ride I'm sold on this pcv. Its got tobe the best $300. I've spent on an upgrade so next time I have the tank off I'll pull the o2 connection and see what that does. Its kind of upsetting to me that yamaha let this problem out the door. This is my 4th yamaha and I'm sold on their bikes, it had tobe a money or epa thing. Well at least its corrected now.

I'd guess EPA. It would be no more difficult or expensive to properly map the fuel injection than it was to intentionally run it lean. But it does allow the bike to pass emissions regulations.

 

[Auburn]

Yes the indicated MPG on the dash becomes uselessly optimistic once you install the PC-V. And to repeat myself, I am sure that SkooterG is correct (as usual) and the O2 sensor is supposed to be disconnected. The only reason we did not was because of confusion/miscommunication at the beginning and fear/laziness now.

Well after yesterdays 400 mile ride I'm sold on this pcv. Its got tobe the best $300. I've spent on an upgrade so next time I have the tank off I'll pull the o2 connection and see what that does. Its kind of upsetting to me that yamaha let this problem out the door. This is my 4th yamaha and I'm sold on their bikes, it had tobe a money or epa thing. Well at least its corrected now.

Yamaha has to tume them the way they are to pass emissions.

 

[Enn]

I also had the smoothness problems on low revs when accelerating out of the roundabouts or slow turns. A year ago my local Yamaha dealer installed me the PCV, the bike got somewhat better, but not as good as it was advertised. Obviously I was a bit disappointed.

Now, having read this thread, I became suspicious, so yesterday I finally had time to take off the tank and check the O2 sensor just to find out it was still connected. I disconnected it and ....WOW! It is so nice and smooooooth now, I can't believe it. What a hell of a difference!!! Like a different bike, absolutely no problems at all any more.

So I confirm here what has been said before: the effect of the PC on smoothness with 02 sensor connected is nearly nothing. Make sure you unplug it.