02 Sensor unplugged effect AFR settings?
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Cruiser
Joined: Apr 2007
Posts: 204
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From: Atascadero, CA
02 Sensor unplugged effect AFR settings?
I just recently started the SERT tuning process on my 08 Ultra. I'm using the Twin Scan II + WEGO IIID to set my VE tables. I just completed several data runs andadustedthe VE tables for my setup using 13.5 AFR in open loop. The Twin Scan unit with the wide band sensors confirmed my AFR that the ECM was putting out was right on 13.5while running atsteady highway speeds. When I was done dialing in the VE tables I changed the AFR tables back to the closed loop settings (14.6) and set the CLB table to 798. I wassure that I would be seeing my new cruising AFRto beabout 14.1.I did one more data run with the wide band sensors still plugged into the the Twin Scan unit to get the new AFR reading. When I got back and down loaded the data it showed my AFR at crusing speed to be 14.6 with the CLB table maxed out, WTF.Is the reason I'm not getting 14.1 because thenarrow band 02 sensorsneed to be connected? Does this also mean that my wide band sensors are useless for data gathering while in closed loop unless I use them as a sniffer at the end of the tail pipe?
This forum has been great in educating me on how to tune my bikebut this is onepice of the tuning puzzleI have not read about yet.
This forum has been great in educating me on how to tune my bikebut this is onepice of the tuning puzzleI have not read about yet.
Tourer
Joined: Oct 2007
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RE: 02 Sensor unplugged effect AFR settings?
I run the Twinscan II plus with Wego IID on my V-Rod, but I don't have the closed loop function ECM (2003). I *think* you are absolutely correct.
The ECM is looking for input from the narrowband sensors, and since the volatge doesn't change, it leans out your cruising mixture to maximum. I would imagine it will throw a code as well.
I *think* the best way to get the data you want for this final run is to put your SERT in DATA mode and ride with your laptop attached.
Again, I don't know for sure if you can read the narrow band 02 sensors in data logging mode with the new super tuner or not.
Does anyone know for sure?
The ECM is looking for input from the narrowband sensors, and since the volatge doesn't change, it leans out your cruising mixture to maximum. I would imagine it will throw a code as well.
I *think* the best way to get the data you want for this final run is to put your SERT in DATA mode and ride with your laptop attached.
Again, I don't know for sure if you can read the narrow band 02 sensors in data logging mode with the new super tuner or not.
Does anyone know for sure?
Outstanding HDF Member
Joined: May 2007
Posts: 2,304
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From: Florida
RE: 02 Sensor unplugged effect AFR settings?
You are correct...with out the stock sensors in the ECM will give you the value in the grid which is 14.6....the bias voltage will not work with a Wide Band Sensor it needs the SWITCHING device (stock Sensor) that sends out a voltage instead of an AFR reading.
Your fuel table won't go to 13.5 in the 90~100 kpa , it maxes out at 13.2.
Your fuel table won't go to 13.5 in the 90~100 kpa , it maxes out at 13.2.
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Cruiser
Joined: Apr 2007
Posts: 204
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From: Atascadero, CA
RE: 02 Sensor unplugged effect AFR settings?
Thank you for clearing that up. I will plug the narrow band sensors back in and bring the lap top along for a ride and see what I get in data mode.
Intermediate
Joined: Nov 2007
Posts: 29
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From: AZ
RE: 02 Sensor unplugged effect AFR settings?
RoadHog,
The CLB table only works with the switching sensors connected. The way you tuned you got exactly what you shouldhave (14.6). You tuned at 13.5 and got 13.5 and then changed the table to 14.6 and then got 14.6. Exactly what the ECM will do in open loop.
Now, in order for the switching sensors to meet the requested 798 mV or approx 14.1, the ECM has to correctfrom 14.6 to 14.1and you will see a fairly large VE Error if you data log with the switching sensors in place...even though your VEs were spot on in open loop.
When I usewide range sensors to tune the closed loop range, I set the AFRto 14.6 and tune the VEs to deliver 14.1-14.2. This minimizes my VE error when itgoes closed loop.
BTW...I would recommend limiting your CLB to about 700 mV. 798mV is very close to the high switching voltage of the sensor (800-850 mV) and can cause control issues as the sensor ages.
The CLB table only works with the switching sensors connected. The way you tuned you got exactly what you shouldhave (14.6). You tuned at 13.5 and got 13.5 and then changed the table to 14.6 and then got 14.6. Exactly what the ECM will do in open loop.
Now, in order for the switching sensors to meet the requested 798 mV or approx 14.1, the ECM has to correctfrom 14.6 to 14.1and you will see a fairly large VE Error if you data log with the switching sensors in place...even though your VEs were spot on in open loop.
When I usewide range sensors to tune the closed loop range, I set the AFRto 14.6 and tune the VEs to deliver 14.1-14.2. This minimizes my VE error when itgoes closed loop.
BTW...I would recommend limiting your CLB to about 700 mV. 798mV is very close to the high switching voltage of the sensor (800-850 mV) and can cause control issues as the sensor ages.
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