O2 sensor with EJK?

[grahamfz07]

Are you guys disconnecting your O2 sensor when running aftemarket exhaust and the EJK?

[GAZ]

Yes. Leave it in but disconnect the connector. EJK will control your fuel/air now instead of the ECU. I wrapped my connector in electrical tape so road dirt wouldn't get in, but I doubt I will ever plug it back in.
 

[grahamfz07]

Yes. Leave it in but disconnect the connector. EJK will control your fuel/air now instead of the ECU. I wrapped my connector in electrical tape so road dirt wouldn't get in, but I doubt I will ever plug it back in.

Ok, thanks. i wasnt sure, the original page i saved with the ejk settings said to leave it,  but now its says disconnect for "race" applications

[grahamfz07]

Finally got a dryish day to go for a ride. The bike seems to run smoother off idle with that O2 sensor disconnected. I cant wait for some dryer days to get out again!

[mericc]

I just mine on still attached lol, no probs

[phicurious86]

Disconnecting the 02 sensor might have been the most difficult part of the whole process for me. Took a lot of wiggling with a flat head to get the two pieces to disconnect.

[hobbs]

I just mine on still attached lol, no probs

 
 
I left mine too. I guess I should disconnect it and see what happens.

[phicurious86]

Disconnecting the 02 sensor doesn't seem to have had any ill effects for my bike. Though I couldn't detect a noticeable difference in ride quality vs. having it in.

[pattonme]

without O2 the stock ECU goes into "safe" mode. With the O2 information it would be adjusting values based on a lookup table. At sea level it won't matter. At 6000ft (hello Colorado) things might get interesting.
 
Ok, I just looked at their product page.
"O2 Sensor - STOCK EXHAUST - Suggest to leave the O2 sensor plugged in.
O2 Sensor - ALL OTHER AFTER-MARKET EXHAUSTS - Suggest to DISCONNECT the O2 sensor ONLY if being used for RACE PURPOSES."
 
So everyone unplugging the sensor is being silly and failed to read the instructions!!
 
The reason you unplug it in RACE PURPOSES is that frequently race gas screws with O2 sensors such that it can send bad data. And furthermore at a race track you don't care about the nuances of F/A balance at various partial throttle openings which is where an O2 sensor is useful.
 
And another reason. Depending on how aggressive the ECU is (thank you enviro-nazis, greenie, and their fellow travelers in the EPA) it may try to target a lean mixture that was forced on them for emissions purposes, especially CARB. So where the ECU is trying to push the mixture lean, the EJK is pushing it rich(er) to fix the driveability issues a lean mixture causes. On a race track, that's just counter productive and you want a richer mix across the board for best performance, which is several points off from the "clean" ratio.
 
I don't know if there is a CARB-only FZ07 ECU map or if all 50 states get to suffer, but *IF* the factory ECU is unduly aggressive at certain RPM and throttle ranges, THEN it can make sense to take the O2 sensor out of the loop to stop the ECU and EJK fighting each other so hard. But EJK vendors can't legally say that or else they are in violation of federal and state law about tampering with an emissions system.

[phicurious86]

Hmmm got a bit of conflicting info then. I saw the directions posted on the ejk page, but was also told that leaving the o2 sensor connected might cause a conflict with the commands sent via the ejk, and that disconnecting the sensor would have no ill effects.
 
Of course I didn't say I wasn't racing the bike, so maybe the assumption was that I was using it for racing.
 

[pattonme]

The ECU sends a wave form of X duration to the injector. The EJK is taking this signal (we'll arbitrarily give it a value of '2') and adds per the tuning setup a '5' to it. So now it's a '7'. The fuel injector runs for however long a '7' would mean.
 
That's admittedly a simplistic description. The EJK no doubt has it's own multi-table lookup such that a 'Green zone 5' means various things depending on spark retard, rpm, gear selection, etc. So instead of a '7' it might be a '3' or a '10'.
 
What the O2 sensor is doing is measuring the exhaust and based on the observational data is changing that initial output ('2') into a '1.5' or a '3' per it's internal rule engine.

[noltz]

So for street use is it advised to have the O2 on or off? Using Yoshimura exhaust on mine.

[pattonme]

on

[noltz]

on

 
 
Thanks!

[tuninghq]

Seems like their is some confusion as to what the stock O2 does and if it should be connected or not.
 
The stock O2 is an emissions component meant to regulate the fueling at low rpm or light load cruising conditions.
It does not control the fuel during acceleration and full throttle as their is heavy load on the engine.
 
The stock O2 sensor maintains an emissions compliant AFR value (usually a lean AFR). When the EJK is added, we are trying to adjust the fueling for all rpm ranges. Having the stock O2 sensor connected will essentially be battling with the EJKs green fuel zone trying to pull out the fuel the EJK is adding.
 
When should it be connected?
If you plan to drive on the streets and want to stay emissions compliant
If you live in California and are going through an emission compliance test
If you are bringing the vehicle in for service work or warranty
 
When should it be disconnected?
If you have a stage 1 kit and want full performance potential.
If you are racing the bike, or drive like you are racing.
If you no longer want to be bound by emissions regulations
 
The difference is minimal with or without the O2 sensor connected.
The main feedback we have received is that disconnecting the O2 sensor smooths out the bikes drivability through the different rpm ranges. It reduces the jerkiness of on/off throttle.
We had riders say that the bike has aggressive engine breaking with the O2 sensor connected and disconnecting the O2 drastically reduced this.
 
Hopefully this clarifies the O2 sensor situation.
Let me know if there is any other questions about this.
 
-TuningHQ

[grahamfz07]

Seems like their is some confusion as to what the stock O2 does and if it should be connected or not. 
The stock O2 is an emissions component meant to regulate the fueling at low rpm or light load cruising conditions.
It does not control the fuel during acceleration and full throttle as their is heavy load on the engine.
 
The stock O2 sensor maintains an emissions compliant AFR value (usually a lean AFR). When the EJK is added, we are trying to adjust the fueling for all rpm ranges. Having the stock O2 sensor connected will essentially be battling with the EJKs green fuel zone trying to pull out the fuel the EJK is adding.
 
When should it be connected?
If you plan to drive on the streets and want to stay emissions compliant
If you live in California and are going through an emission compliance test
If you are bringing the vehicle in for service work or warranty
 
When should it be disconnected?
If you have a stage 1 kit and want full performance potential.
If you are racing the bike, or drive like you are racing.
If you no longer want to be bound by emissions regulations
 
The difference is minimal with or without the O2 sensor connected.
The main feedback we have received is that disconnecting the O2 sensor smooths out the bikes drivability through the different rpm ranges. It reduces the jerkiness of on/off throttle.
We had riders say that the bike has aggressive engine breaking with the O2 sensor connected and disconnecting the O2 drastically reduced this.
 
Hopefully this clarifies the O2 sensor situation.
Let me know if there is any other questions about this.
 
-TuningHQ

Thanks for the info! I have been running mine disconnected now for a while and the bike runs great, much smoother on the throttle

[pattonme]

> We had riders say that the bike has aggressive engine breaking with the O2 sensor connected and disconnecting the O2 drastically reduced this.
 
Hmm, must be some interplay between TPS indicating closed throttle, O2 readings and bleed servo actuation. Or at least in open-loop the ECU doesn't resort to ~zero'ing the amount of fuel. maybe if it also detected for unburnt hydrocarbons (so lean nothing is burning) it wouldn't be so simple-minded about fuel shutoff.
 
Thanks for clarifying.

[JA50N]

Has anybody tried just disconnecting the O2 sensor even without a EJK with an aftermarket exhaust? Apparently it doesn't pop an ECU code based on the number of people running like that in this thread.  I wonder if that would help with on/off throttle transition smoothness.
 
 

[pattonme]

@tuninghq any chance you can post the ECU's pulse signals during 3rd or 4th gear decel from 6000RPM? And if not the O2 signals then a AF mixture obtained independently this period, with and without O2 connected? Also say doing 10-15mph in first as one switches on/off the throttle? The traces would be from a dyno session or three.
 
Seems to me this is an opportunity for an EJK to provide a definitive and lasting solution to the repeated inability of Yamaha fuel engineers to do their damn job.

[catfish]

Seems like their is some confusion as to what the stock O2 does and if it should be connected or not....
Hopefully this clarifies the O2 sensor situation.
Let me know if there is any other questions about this.
 
-TuningHQ

I've had a dyno-shop owner tell me that unplugging an O2 sensor and leaving it in place is bad for the sensor. Claimed the heater keeps the sensor hot enough that it doesn't get contaminated with exhaust crap. He said if you plan to unplug the sensor long term, remove the sensor & install a plug. That way the sensor is still good, if you plan to reuse it again later.
 
When I dyno-tuned an Aprilia Caponord years ago, we just adjusted the AF1 table to ignore the O2 sensor and left 'em plugged in.
 
 
Catfish ...
 
 

[pattonme]

@catfish now THAT is a fantastic writeup. Wow!

Caponord motors do not like to run lean at low RPMs. They are more prone to stalling, roughness, and pinging. This region is hard to test on an eddy-current dyno. It took many test rides and adjustments to figure out that the CO should be at least 3% (AFR of 13.4 or less) to run smoothly down there.

 
Actually I think the 3% thing is nearly universal on small CC internal combustion engines regardless of configuration.
 
I expect the twin in the FZ exhibits similar tendencies and why there is also an active thread on people stalling their bikes while still moving. Now that's grounds for a NHTSA recall for safety hazard and forcing Yamaha to fix the fuel map. AFAIK emissions testing is done at a fixed (set of?) moderate speeds and not at idle or basement RPM, so getting CO above ~2% shouldn't trigger any compliance issues.
 

[tuninghq]

@tuninghq any chance you can post the ECU's pulse signals during 3rd or 4th gear decel from 6000RPM? And if not the O2 signals then a AF mixture obtained independently this period, with and without O2 connected? Also say doing 10-15mph in first as one switches on/off the throttle? The traces would be from a dyno session or three. 
Seems to me this is an opportunity for an EJK to provide a definitive and lasting solution to the repeated inability of Yamaha fuel engineers to do their damn jobs

@pattonme, 
We may be able to get some of this info out to you once we have the bike back in the shop for the remaining exhausts we are testing.
Our new software is now available too so we should have more info available. Stay Tuned on this...
 
We can't necessarily throw the Yamaha engineers under the bus. It is the EPA that puts the regulations on everything fuel injected. Any OEM engineer has to create a fuel system that complies with regulations.
Just look at Harleys; those run so lean stock, they will burn the hairs right off your leg. Add intake and exhaust and it is even worse. Our EJK makes a Harley run like a whole new bike.
 
The Yamaha cruiser models actually have a clever system on them that allows them to meet EPA emissions regulations without compromising the fueling completely.
It is referred to as an AIS (air induction system) on Yamaha cruiser models or a PAIR Valve (Pulsed Air Induction Reed Valve) on other brands like Honda & Kawasaki. These systems allow fresh air into the exhaust so that the exhaust fumes comply with the emissions regulation. The fresh air getting into the exhaust makes the AFR show leaner at the tailpipe than the bike is actually running. 

[pattonme]

We can't necessarily throw the Yamaha engineers under the bus. It is the EPA ...

 
And yet after getting roundly criticized in the press, Yamaha et. al. somehow manage to fix their fuel maps in the next year's bike (or can do a reflash at dealer) and still stay in compliance. I call it doing a shoddy job.
 
The EPA and CARB in particular is being ridiculous in what they're allowing. But if such simple technologies like PAIR could have been brought to bear, then another sharp poke at Yamaha for choosing to not avail themselves of it.

[FZRDR]

Quite an interesting dialogue,,,,,,please continue .....
 
I have learned more about the complexities of FI mapping in this thread then anywhere else!
I'm  just curious what THQ was alluding to in this comment below?
 
 
("Our new software is now available too so we should have more info available. Stay Tuned on this...")
 
 
 

[tuninghq]

("Our new software is now available too so we should have more info available. Stay Tuned on this...")
 
 

As you may or may not know, Dobeck Performance has a new dyno we are manufacturing. It is called the AXIS Dyno. 
This is the dyno that has been used for all the FZ-07 testing. 
 
When the exhaust testing was conducted, our dyno software was still being finalized and tested.
During this time, we were using Datamite dyno software. It gave us the info we needed and sufficed for the time being.
 
Now our own software is available and will provide much more information that we can share with you guys and in a format that should be easier to analyze.
Like pattonme's request for pulse width during a certain rpm range. I'll have to double check with R&D, but our software should be able to easily display that info.
 
As usual... Stay Tuned for more!
 
-TuningHQ