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Logging Wideband O2 Via The TGV Sensor Input


Turkeylord

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Started this conversation in the WDYDTY4GLT thread, but thought it needed it's own thread.

 

So I bought an AEM FailSafe WBO2 gauge, and it's great except that it's not compatible with Cobb's AccessTuner Race. Logging with a laptop is not super convenient anyway, and I wanted to be able to log with my AccessPort only.

 

So I found this thread a while back and have slowly been working on it. I got the 0-5v out from my gauge wired up to my left TGV input last night and have been playing with it a bit and it's not quite right.

 

So here are some graphs from a pull I did earlier. Top graph is from the ECU, showing the WBO2 (calculated from TGV volts according to AEM's formula), the stock A/F sensor, and the raw TGV volts. Bottom graph is from the FailSage gauge directly.

 

http://i.imgur.com/cKbCOfP.png

 

It's reading high, but mostly correlated at the start, but when I go WOT is goes back up around 5v (lean).

 

I talked to AEM briefly and they seemed somewhat familiar, saying there might be a "5v pull-up" or something in the ECU. Anyone know what that means exactly, or how to counteract it?

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I'll be deleting my TGVs(already have the delete kit, not installed yet) as soon as I get make sure my cars running fine and passes smog.

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the innovate sensors are very peculiar with their grounding, i know this from my drag car. so maybe that is something you should check into

 

He's using an AEM though. I do agree with the innovate gauges being picky about their grounds. I had issues getting my Trans AM one to work right due to grounding.

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I'm not sure why AEM's formula for converting voltage to AFR doesn't just work, but my guess is that you'll just need to fudge the numbers in that formula until the results look like the stock sensor's results. (Keeping in mind that the stock sensor won't read less than 11.2 or so.)

 

Are you sure it's reading lean when you go WOT, or is that happening when you lift the throttle? Maximum lean readings when you lift are normal. Maximum lean at WOT would be weird though.

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also, the tgv input shouldn't have a pull-up resistor.

 

yes, do ground your wbo2 signal gnd.

BtSsm - Android app/Bluetooth adapter. LV, logging, gauges and more. For 05-14 Legacy (GT, 2.5, 3.0, 3.6), 02-14 WRX, 04-14 STi, 04-14 FXT, 05-09 OBXT
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I have this exact gauge in the car wired to my passenger side TGVs. I use 2.375x + 7.613835. From my experience, trying to calibrate it with the front O2 is hard due to the delay and the slow response of the front o2. I had better results moving the Front O2 into the down pipe but it was still off a bit. I tried changing the multiplier and keeping the constant and it was still off. I tried a slope with the lowest and highest with what I saw, it was still off. I finally did it this way:

 

Plug your laptop into the AEM O2 via the AEM software. Clear the data and take a fresh log at idle while also logging TGV volts via the AP. (Average AFR via AEM Software)=(2.375*Average TGV Volts) + B. Solve for B.

 

It now matches the gauge logs within .2 at both idle and WOT. You can check it by clearing the logger on the gauge(logs automatically and saves the last ~3 hours) and doing a WOT pull. Compare your log with your formula.

Edited by bnguyenbb6
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I've been thinking about doing this for some time. I was considering placing it in the bung in Cobb's DP and wiring it to my deleted TGV. Then setting up a custom field in my wonderful BtSsm app to read WBO2 through the TGV.

 

As I'm doing some research, I'm trying to figure out the best way to do this. At first I thought I could just buy the sensor and wire it up. However, now I'm thinking that if I do that, I won't have any "truth" data to compare it against to make sure my conversion in the TGV input voltage is correct.

 

Would my assessment be accurate? Do I need to get the whole failsafe SW package to figure out the conversion equation to get the input voltage in the TGV correct?

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oh man, I guess i'm getting TGV deletes... I guess at least I can check my gaskets and replace at least.

 

I looked at other potential inputs and didn't find any good ones. the 07+ air pump only has a ms-based input, so no go there.

 

So two questions:

  1. what are the downsides to TGV deletes? Cold start engine unhappiness?
  2. Are people using direct wideband outputs or feeding the wideband to their manufacturers sensor box and then taking the wideband output from there to the TGV?

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I've been thinking about doing this for some time. I was considering placing it in the bung in Cobb's DP and wiring it to my deleted TGV. Then setting up a custom field in my wonderful BtSsm app to read WBO2 through the TGV.

 

As I'm doing some research, I'm trying to figure out the best way to do this. At first I thought I could just buy the sensor and wire it up. However, now I'm thinking that if I do that, I won't have any "truth" data to compare it against to make sure my conversion in the TGV input voltage is correct.

 

Would my assessment be accurate? Do I need to get the whole failsafe SW package to figure out the conversion equation to get the input voltage in the TGV correct?

 

At least you could just plug in the AEM formula to start. It will probably be awfully close. The "stock" AEM formula is AFR(Gas)=(2.375 * Volts) + 7.3125 but as bnguyenbb6 said, that can sometimes need a slight tweaking.

 

snow, if you're using BtSsm w/TGV input, the custom formula would just be (2.375 * x / 50) + 7.3125 (the "x/50" converts the raw value into Volts)

For anyone who hasn't seen the AEM doc: http://aemelectronics.com/files/instructions/30-4900%20Wideband%20Failsafe%20Gauge.pdf

AEM_WBO2_connector.PNG.b7c5c60091a412b5eb5e505deb6f7c17.PNG

AEM_WBO2_table.PNG.b133885c9599b446eb07630396e51151.PNG

BtSsm - Android app/Bluetooth adapter. LV, logging, gauges and more. For 05-14 Legacy (GT, 2.5, 3.0, 3.6), 02-14 WRX, 04-14 STi, 04-14 FXT, 05-09 OBXT
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oh man, I guess i'm getting TGV deletes... I guess at least I can check my gaskets and replace at least.

 

I looked at other potential inputs and didn't find any good ones. the 07+ air pump only has a ms-based input, so no go there.

 

So two questions:

  1. what are the downsides to TGV deletes? Cold start engine unhappiness?
  2. Are people using direct wideband outputs or feeding the wideband to their manufacturers sensor box and then taking the wideband output from there to the TGV?

 

1. Regarding TGV delete downsides: I haven't noticed any issues, but then I don't drive mine in the dead of winter. Note that after you start your engine, the moment you touch the accelerator at all, the TGVs will fully open for the rest of the driving "session". So they're not in effect for very long if you start up and go.

 

2. The WBO2 signal does have to come from the manufacturers interface module (0-5V). Unfortunately the raw data from the sensor itself is pretty meaningless :(

BtSsm - Android app/Bluetooth adapter. LV, logging, gauges and more. For 05-14 Legacy (GT, 2.5, 3.0, 3.6), 02-14 WRX, 04-14 STi, 04-14 FXT, 05-09 OBXT
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Went back through and read more carefully...

 

The brown wire should be connected to an analog ground input for best results. If the EMS, logger or similar device does not have an analog ground input, the brown wire should be connected to a sensor ground. If no sensor ground is available, the brown wire should be connected to a power ground. The brown wire must be connected in order to obtain correct AFR and MAP readings from the analog output(s).

I'm guessing that's my problem then.

 

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2. The WBO2 signal does have to come from the manufacturers interface module (0-5V). Unfortunately the raw data from the sensor itself is pretty meaningless :(

 

so this means I need to buy the whole AEM package and not just the sensor.

 

so reading the failsafe manual correctly, I have to have their gauge (pod-thing) installed somewhere? it seems like it (the physical gauge) is the receiver of the WBO2 sensor signal, and also the sender of the converted to 0-5V signal.

 

after poking around their website more, I think what i really want is this (no gauge):

 

http://www.aemelectronics.com/products/wideband-uego-air-fuel-controllers/inline-wideband-uego-afr-controller

 

just the sensor, UEGO box, and signal wires. that would do the trick for me, I believe?

 

anyway, I'll stop taking over your thread. thanks for the inspiration!

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so this means I need to buy the whole AEM package and not just the sensor.

 

so reading the failsafe manual correctly, I have to have their gauge (pod-thing) installed somewhere? it seems like it (the physical gauge) is the receiver of the WBO2 sensor signal, and also the sender of the converted to 0-5V signal.

 

after poking around their website more, I think what i really want is this (no gauge):

 

http://www.aemelectronics.com/products/wideband-uego-air-fuel-controllers/inline-wideband-uego-afr-controller

 

just the sensor, UEGO box, and signal wires. that would do the trick for me, I believe?

 

anyway, I'll stop taking over your thread. thanks for the inspiration!

 

yes! perfect product for logging

BtSsm - Android app/Bluetooth adapter. LV, logging, gauges and more. For 05-14 Legacy (GT, 2.5, 3.0, 3.6), 02-14 WRX, 04-14 STi, 04-14 FXT, 05-09 OBXT
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Yep, this one would work too:

 

[ame=http://www.amazon.com/Innovate-Motorsports-Digital-Wideband-Controller/dp/B00FFTAJPC/ref=pd_sim_sbs_263_3?ie=UTF8&refRID=0XV6DGFD6AJ2NZ77ZMBN]Amazon.com: Innovate Motorsports (3877) LC-2 Digital Wideband Lambda Controller Kit with O2 Sensor: Automotive[/ame]

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