O2 sensor for A/F Gauge
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O2 sensor for A/F Gauge
Hi folks,
I'm getting ready to install an A/F gauge in my 89 TII and I'm looking for some recommendations on where to get a connection from the O2 sensor. Am I better off adding adding a new tap for a new wideband O2 sensor dedicated for the A/F gauge or should I tap into the factory O2 sensor? If so, is is better tap from the ECU or is there a better way? I'm looking for best practices type of advice. Many thanks!
I'm getting ready to install an A/F gauge in my 89 TII and I'm looking for some recommendations on where to get a connection from the O2 sensor. Am I better off adding adding a new tap for a new wideband O2 sensor dedicated for the A/F gauge or should I tap into the factory O2 sensor? If so, is is better tap from the ECU or is there a better way? I'm looking for best practices type of advice. Many thanks!
#2
Rotary $ > AMG $
iTrader: (7)
Widebands: What you think you know, but don't.
A lot of people are confused regarding widebands. This post will hopefully set everyone straight.
A "Wideband 02" (AKA "WB02" or just "WB") is a system. Unlike the common narrowband O2 sensors that everyone is used to, Widebands need more than just the sensor to work.
There are two parts to a WBo2 system. The sensor and the controller.
The sensor looks much like it's narrowband counterpart. It screws into the exhaust and has wires coming out of it. The way the WB sensor works, though, is much different than a narrowband.
A controller is required to operate the WB sensor. Unlike the stock narrowband sensor, which simply generates a voltage based on A/F ratio, the WB sensor requires sophisticated circuitry to measure A/F ratios. There is no wire you could tap off the sensor and have it put out a voltage like the narrowband sensors do.
A Bosch or NGK Wideband o2 sensor is useless without a controller
The WB controller connects to the WB sensor and reads the A/F ratio. The controller can then do anything it wants with the data. Depending on the brand/type of controller you buy, it could do one or more, or all of the following:
Analog outputs
Many controllers have one or more analog outputs. These outputs generate a voltage based off of the current A/F ratio reading and can be scaled in different ways. Most WB Controllers have two outputs, one "Simulated Narrowband" (I'll use SNB for short) output and one "Wideband" output.
The SNB output is generated by the controller by scaling and manipulating the signals from the Wideband sensor to simulate the 0-1 volt output of the stock narrowband. Because of this scaling and manipulation, the SNB output is typically not useful for reading accurate A/F ratios, but it can be used in place of the stock narrowband sensor. This would allow you to eliminate the stock sensor. In order to do this, you would remove the stock narrowband sensor and connect the SNB output wire to the ECU via the wire that the stock sensor was connected to. The SNB output will act just like the stock narrowband o2 sensor and keep the ECU happy. It is worth noting that the stock O2 sensor location is typically not suitable for the WBo2. Refer to the instructions of your particular WB for information on proper location.
The WB output is typically a 0-5 volt representation of the A/F ratio. This output is scaled, but not manipulated like the SNB output so it can be used to accurately read A/F ratios. Different controller brands scale this 0-5v output differently. Some controllers allow you to program how you want the output scaled, others have a fixed scale. Most controllers have a linear output, meaning the output is directly proportional to the A/F ratio. It is important to know if the controller you are buying has a linear output.
So you have this 0-5volt output, what do you do with it? You connect it to an engine management system that can convert the output back to a human-readable A/F ratio.
Connecting to the Rtek Stage 2
In order to connect a WBo2 to the Rtek, as stated above, you need a WB *system*; A sensor and a controller. The controller must have a linear 0-5volt analog output. The particular scaling that the controller uses is not an issue as the Rtek7 PocketLOGGER software can be configured to convert any linear scaling back to an A/F ratio. The important part is that the 0-5volt output must be linear or the PocketLOGGER software will display inaccurate A/F ratios.
So, by connecting the 0-5v output of the WB02 controller to the Rtek ECU, the ECU will convert the voltage into digital data. Once the ECU has this data, you can use the Rtek PocketLOGGER software to display and datalog actual A/F ratios.
Instructions for connecting the WB to the ECU are in the Rtek7 Stage 2 instruction manual that can be found on our site.
-Mike
A "Wideband 02" (AKA "WB02" or just "WB") is a system. Unlike the common narrowband O2 sensors that everyone is used to, Widebands need more than just the sensor to work.
There are two parts to a WBo2 system. The sensor and the controller.
The sensor looks much like it's narrowband counterpart. It screws into the exhaust and has wires coming out of it. The way the WB sensor works, though, is much different than a narrowband.
A controller is required to operate the WB sensor. Unlike the stock narrowband sensor, which simply generates a voltage based on A/F ratio, the WB sensor requires sophisticated circuitry to measure A/F ratios. There is no wire you could tap off the sensor and have it put out a voltage like the narrowband sensors do.
A Bosch or NGK Wideband o2 sensor is useless without a controller
The WB controller connects to the WB sensor and reads the A/F ratio. The controller can then do anything it wants with the data. Depending on the brand/type of controller you buy, it could do one or more, or all of the following:
- Output the A/F Ratio to a built in display
- Output the A/F Ratio to an external screen
- Output digital data to a serial port for display/datalogging with a PC or PDA
- Output analog data (a voltage representation of the current A/F ratio) to a wired output.
Analog outputs
Many controllers have one or more analog outputs. These outputs generate a voltage based off of the current A/F ratio reading and can be scaled in different ways. Most WB Controllers have two outputs, one "Simulated Narrowband" (I'll use SNB for short) output and one "Wideband" output.
The SNB output is generated by the controller by scaling and manipulating the signals from the Wideband sensor to simulate the 0-1 volt output of the stock narrowband. Because of this scaling and manipulation, the SNB output is typically not useful for reading accurate A/F ratios, but it can be used in place of the stock narrowband sensor. This would allow you to eliminate the stock sensor. In order to do this, you would remove the stock narrowband sensor and connect the SNB output wire to the ECU via the wire that the stock sensor was connected to. The SNB output will act just like the stock narrowband o2 sensor and keep the ECU happy. It is worth noting that the stock O2 sensor location is typically not suitable for the WBo2. Refer to the instructions of your particular WB for information on proper location.
The WB output is typically a 0-5 volt representation of the A/F ratio. This output is scaled, but not manipulated like the SNB output so it can be used to accurately read A/F ratios. Different controller brands scale this 0-5v output differently. Some controllers allow you to program how you want the output scaled, others have a fixed scale. Most controllers have a linear output, meaning the output is directly proportional to the A/F ratio. It is important to know if the controller you are buying has a linear output.
So you have this 0-5volt output, what do you do with it? You connect it to an engine management system that can convert the output back to a human-readable A/F ratio.
Connecting to the Rtek Stage 2
In order to connect a WBo2 to the Rtek, as stated above, you need a WB *system*; A sensor and a controller. The controller must have a linear 0-5volt analog output. The particular scaling that the controller uses is not an issue as the Rtek7 PocketLOGGER software can be configured to convert any linear scaling back to an A/F ratio. The important part is that the 0-5volt output must be linear or the PocketLOGGER software will display inaccurate A/F ratios.
So, by connecting the 0-5v output of the WB02 controller to the Rtek ECU, the ECU will convert the voltage into digital data. Once the ECU has this data, you can use the Rtek PocketLOGGER software to display and datalog actual A/F ratios.
Instructions for connecting the WB to the ECU are in the Rtek7 Stage 2 instruction manual that can be found on our site.
-Mike
#4
MECP Certified Installer
#5
What is the best wideband to use on the rtek 2.0 to 2.1 i have been looking through inavate, aem and autometer, none of them are saying linear output. They are saying 0v-5v anolog. Is that good enough for the system. I DID RUN ACROSS THIS A PLX DM-200 It has a lcd multi display 60mm gauge. i dont know never heard the name, can someone help with this. Thanks
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#10
So your saying that as long as it has a 0v-5v output the pocketlogger will data log it ? this is my main concern, for i want to be able to have it all on one sheet. As well as i dont want to damage the rtek system. Thanks for anyones input.
#11
Ok its done just bought a Innovate MTX-L Digital Wideband Air Fuel Gauge Kit, Its has two linear 0v-5v outputs and the digietal direct setup with software , wish me luck and i thank the rx7 club members for helping me get my car back together. At the end of it all this, my t2 will be running the rtek2.1 inovate wideband mtx-l 720cc injection, a/r t4 .60/1.00 quickspool 12 to 15psi. hks blowwoff an wastegate 40mm rebuilt with lighter spring, hks twinpower ingition, with a 2nd stage act sprung 6 puck clutch, should be nice after i get a good tune, im waiting on a reply from a place in columbus ohio, thats the closest one i can find.
#12
yea my guage i just wired right to the o2 sensor. it works at least and shows a little over half through the optimal range unless im decerlerating right after accelerating. after that it just leans out a little and returns to the optimal range. i guess it does get richer when throttling.
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