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Discussion Starter · #1 ·
Disclaimer: I take 0 credit for coming up with this. I merely combined 2 other methods into something that worked for me. This was done in version 4.2.12 because that's the version that my tuner wanted me to use.

FIrst you need to decide how you are going to connect to the AC pressure switch cabling. I unplugged the connector and pinned directly into the plug with spade connectors with one prong clipped-off of a temporary wire to the wideband's analog output. Since you're connecting your wideband's analog data into the ECM this way, you 'll need to use the signal AND sensor ground. I used the AEM 30-0300 X-Series, which uses WHITE for the 0-5vdc and BROWN for the sensor ground. The 0-5vdc (white) connects to the PRESS SENS SIG (GREEN/BLACK) on pin C and the ground (brown) to the LOW REF (TAN) wire on pin A. You can accomplish this with the aforementioned method, or more semi-permanently using relays and a switch inside of the car, or a manual switch at the sensor.
502831

Now that the hard part is over, we set up the VCM scanner to look for the signal.

For this to work, you need to log AC Pressure Sensor voltage. Right-click the channel list and select "ADD CHANNEL" to add the Channel AC Pressure Sensor; make sure the units are volts.
502832


Next you need to setup a user math parameter that will take the AC pressure sensor voltage and calculate the AFR based on AEM's voltage output. Select TOOLS>MATH PARAMETERS. Select one of the unused User Maths. I named mine AFR and gave the abbreviation AFR (you can name it whatever you want to). Take this next line and cut and paste it into the Expressions field. Make sure to copy everything including the open parenthesis:

([7101]*2.3750)+7.3125

7101 is the PID the ECU uses for the AC pressure sensor, and the other math gets you a pretty spot-on (with my gauge anyway) AFR reading. IF you find that yours is a bit off, you can adjust for a voltage drop by adding and subtracting from the 7.3125. One of the source threads I referenced below uses ([7101]/.5)+10, but it wouldn't match up for me as well as the above formula.

502833

Now we add a Chart to display the awesomeness we've created. Right-click in the Chart v/s Time field and select CHARTS LAYOUT. If you have room inside a group, select the group header and select ADD SERIES at the top. If not, add a new group first. I like to limit the display to 4 at a time so I can see things better. Select PARAMETER, and scroll down to the MATHS>USER DEFINED>AFR (or whatever you named it). Set the Unit to "Air-Fuel ratio 14.7 -Gasoline" and the decimals to 2. I entered 20 as the max and 8 as the min, as that's what my gauge displays. You can add a reference line at a target AFR as well.

502834


502835


Now you can see the wideband's output displayed as AFR in your scanner!

502836


Make sure that you save the layout, or you might have to do it over again when you close the VCM Scanner tool.

Sources:
 

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Its waaaaaaaaaaay easier if your wideband has an logging output. Most of them do. All you do is plug that logging output into another usb port of your computer or if you only have one usb, you can use a use expander. You add a channel for you wideband (hp tuners supports AEM, Innovate. plx and one other I cant remember). Then you create your histogram. No wiring at all except plugging in the usb. Hp tuners picks it up automatically and will populate your histogram with your afr for rpm and load. This is for the regular hp tuners also.
 

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Discussion Starter · #3 ·
Ok, so the above comment opened a door that I didn't know existed, and Google showed me some import forums that (kinda) supported it, so i looked a bit deeper, and got it to work. It's not free like the method described above, but at less than $20, it has it's merits, and will be easier to use in the future (and i can log AFRs and use the AC at the same time).

This is one of the cables I used:
502907

This is the second:
502908

Now, any serial cable, or pigtail, or bare end should work (in theory), but these are the ones I ordered, and they worked. I have a bare serial female end coming, as i don't like the small gauge wire in this one for longevity and possible voltage drop.

Starting with the installation again, I cut off the male end of the cable and stripped back the wires. You need to connect to Pin 2 for data (BLUE wire from the gauge harness) and pin 5 goes to ground (I used the ground wire for the wideband) as indicated in you instruction manual. I used the AEM 30-0300 and here is that page:
502910

NOTE: The above picture shows the MALE end. If you have a female end (as I did) the pins are reversed. I have found that if you use a standard cable, Pin 2 should correlate to RED (Data) and Pin 5 to Green (gound).

Now plug the serial cable into the serial to USB conversion cable and plug it in. Some of the resources say that you can use a USB hub if you don't have enough connections, but I cannot confirm that. I had the Hp Tuners cable and the Wideband cable in seperate USB plugs on my laptop.

Now that the hard part is done (again), we go to the VCM scanner to set it up. The setup is similar to the "through the AC" method, with some slight differences.

First, add a channel:
502911


This time we use an external source (that you just created and plugged into the USB connection).

Then we create the histogram for the AFRs:
502912

FIrst, select the Group you want it in, then add a new series, and then select the parameter.

502913

Then select your wideband model under >external inputs>serial port>

502914


BOOM, you're done. I plan on using BOTH methods to compare the accuracy between them in the future and will report back.
 

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Disclaimer: I take 0 credit for coming up with this. I merely combined 2 other methods into something that worked for me. This was done in version 4.2.12 because that's the version that my tuner wanted me to use.

FIrst you need to decide how you are going to connect to the AC pressure switch cabling. I unplugged the connector and pinned directly into the plug with spade connectors with one prong clipped-off of a temporary wire to the wideband's analog output. Since you're connecting your wideband's analog data into the ECM this way, you 'll need to use the signal AND sensor ground. I used the AEM 30-0300 X-Series, which uses WHITE for the 0-5vdc and BROWN for the sensor ground. The 0-5vdc (white) connects to the PRESS SENS SIG (GREEN/BLACK) on pin C and the ground (brown) to the LOW REF (TAN) wire on pin A. You can accomplish this with the aforementioned method, or more semi-permanently using relays and a switch inside of the car, or a manual switch at the sensor.
View attachment 502831
Now that the hard part is over, we set up the VCM scanner to look for the signal.

For this to work, you need to log AC Pressure Sensor voltage. Right-click the channel list and select "ADD CHANNEL" to add the Channel AC Pressure Sensor; make sure the units are volts.
View attachment 502832

Next you need to setup a user math parameter that will take the AC pressure sensor voltage and calculate the AFR based on AEM's voltage output. Select TOOLS>MATH PARAMETERS. Select one of the unused User Maths. I named mine AFR and gave the abbreviation AFR (you can name it whatever you want to). Take this next line and cut and paste it into the Expressions field. Make sure to copy everything including the open parenthesis:

([7101]*2.3750)+7.3125

7101 is the PID the ECU uses for the AC pressure sensor, and the other math gets you a pretty spot-on (with my gauge anyway) AFR reading. IF you find that yours is a bit off, you can adjust for a voltage drop by adding and subtracting from the 7.3125. One of the source threads I referenced below uses ([7101]/.5)+10, but it wouldn't match up for me as well as the above formula.

View attachment 502833
Now we add a Chart to display the awesomeness we've created. Right-click in the Chart v/s Time field and select CHARTS LAYOUT. If you have room inside a group, select the group header and select ADD SERIES at the top. If not, add a new group first. I like to limit the display to 4 at a time so I can see things better. Select PARAMETER, and scroll down to the MATHS>USER DEFINED>AFR (or whatever you named it). Set the Unit to "Air-Fuel ratio 14.7 -Gasoline" and the decimals to 2. I entered 20 as the max and 8 as the min, as that's what my gauge displays. You can add a reference line at a target AFR as well.

View attachment 502834

View attachment 502835

Now you can see the wideband's output displayed as AFR in your scanner!

View attachment 502836

Make sure that you save the layout, or you might have to do it over again when you close the VCM Scanner tool.

Sources:
Wow can't believe i stumbled across this! Thank you! Do you have the math formula to get this into lambda?
 

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Discussion Starter · #6 ·
Wow can't believe i stumbled across this! Thank you! Do you have the math formula to get this into lambda?
Not sure if the answer is as easy as this, but change the "chart display layout editor" Unit to Lambda and it might work fine. I do not have my HPTuners interface here at the moment (shared among a few of us). Try and let us know!
506714
 

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I got it working with a formula. The wideband directions have the parameter to bring it in as lambda. And yes again 05 06 have an advantage over us 04 guys lol.
 

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Discussion Starter · #10 ·
I looked at it again. If you change the parameter to Lambda and the min and max to 0 and 2 it tracks with the same AFR readings.
 

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Using the canbus aem wideband makes things much easier but might only work on 05-06?
Any details on this? I'm just gonna get a new WB and trying to figure out which one to get. I'm either gonna make a usb cable as detailed in post #3 above or go the CAN route since I have an 05. Searches are spotty because they're mostly covering setup in VCM scanner, I'm looking for how to actually hook a WB up to the car physically. Is there a harness in the dash? Do I wire it into the obd2 port somehow? How do the CAN compatible WBs work?
 

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Any details on this? I'm just gonna get a new WB and trying to figure out which one to get. I'm either gonna make a usb cable as detailed in post #3 above or go the CAN route since I have an 05. Searches are spotty because they're mostly covering setup in VCM scanner, I'm looking for how to actually hook a WB up to the car physically. Is there a harness in the dash? Do I wire it into the obd2 port somehow? How do the CAN compatible WBs work?
It has a pass-through obd2 plug. Literally plug that in then the hptuner and set up the correct math
 

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It has a pass-through obd2 plug. Literally plug that in then the hptuner and set up the correct math
Jeez, literally just googling aem can bus and looking at the pic would have answered this question. Classic overthinking.
 

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Very sorry to bring up the dead but it is incredible difficult for me to learn by reading

So you use MPVI2 non pro version to do this? Then you plug the serial to usb adapter into your laptop? This will be a dumb question but this means that you leave the usb cable hanging somewhere in your car until ready for use and then plug into your laptop correct? This is for use in a non can bus system or only for the can bus? I'm attempting this for my truck and it does not have canbus and from what I have read the canbus just uses the passthrough like mentioned above

I tried to PM but obviously cannot since this is a new account. Sorry for dragging up old stuff and clouding the forum

Thanks,
SF


edit: repetitive wording
 

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Discussion Starter · #15 ·
Very sorry to bring up the dead but it is incredible difficult for me to learn by reading

So you use MPVI2 non pro version to do this? Then you plug the serial to usb adapter into your laptop? This will be a dumb question but this means that you leave the usb cable hanging somewhere in your car until ready for use and then plug into your laptop correct? This is for use in a non can bus system or only for the can bus? I'm attempting this for my truck and it does not have canbus and from what I have read the canbus just uses the passthrough like mentioned above

I tried to PM but obviously cannot since this is a new account. Sorry for dragging up old stuff and clouding the forum

Thanks,
SF


edit: repetitive wording
yes, I have the USB cable coiled up in the console until I need it. this method uses non-canbus. I was very surprised how easy the USB method was to setup.
 

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Perfect thank you! I plan on picking up my wideband this weekend and putting on some headers. Didn’t have the pro version and needed AFR to try and tune them in
 
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