Logging AFR with AP v3 and AEM UEGO - How to wire it up.

[adesso]

Originally Posted by GK1707

Can anyone confirm for 04 STi that the white wire in the o2 harness is the one to tap also?

Its the same wire as in the original post. I just did this with my 04 STi a couple of weeks ago.

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[GK1707]

Originally Posted by adesso

Its the same wire as in the original post. I just did this with my 04 STi a couple of weeks ago.

Thanks man, doing mine soon!

[ericsson]

I've had this done to my car and it's very convenient for AP to log from wideband, BUT now this sets my O2 sensor in "not ready" state and makes the emission state inspection fail.. Anyone else run into this?

[TheTooTall]

Originally Posted by chchchino

worth it to note this will only work with a protuner. Im pretty sure ATR does not have custom sensor logging enabled.

So I know I'm late to this party but can anyone confirm that you have to have protuner in order to log custom sensors?

[slow.wagon]

Originally Posted by TheTooTall

So I know I'm late to this party but can anyone confirm that you have to have protuner in order to log custom sensors?

No, you only need the updated version of ATR. I don't remember the exact version, I think it was introduced after they started forcing people to take the class. I don't run the new version of ATR so I just tap into the TGV harness and do the conversion in excel, works perfectly fine and will work with all versions of ATR.

[JSR84]

I could be misunderstanding what you're saying so forgive me but... If you want to log/view custom sensor inputs you need to supply ATR with the voltage over data point information for that particular sensor so it can be converted into usable information. For that, you would need access to ATR or a Pro Tuner to do so.

[slow.wagon]

Originally Posted by JSR84

I could be misunderstanding what you're saying so forgive me but... If you want to log/view custom sensor inputs you need to supply ATR with the voltage over data point information for that particular sensor so it can be converted into usable information. For that, you would need access to ATR or a Pro Tuner to do so.

No need for an apology. I probably didn't read something and responded to hastily. To "log" AFR there are a few options and scenarios.

1. Get the latest version of ATR, wire up the AFR serial output with a DB9 and the appropriate USB converter if you don't have a serial port on your PC. To log with this method, you will both the AccessPort and the UEGO plugged into different USB ports simultaneously. This is the suboptimal option since it requires a lot of clumsy wiring, you will have sync issues with aligning the UEGO output with the AccessPort.


2. Use the latest version of ATR, wire up the AFR output to either the Rear O2 Sensor or TGV. The custom sensor option in ATR allows you to log this data natively and it is automatically converted and displayed in the right units. This is probably the most ideal path but it wont work for folks that run an ATR version that was released before 2016.

3. The last and most universal option (for folks with deleted TGVs). Wire the UEGO into the TGV (its just one wire). Log like usual but include the appropriate TGV voltage (left or right). When you log like this, all you need to do is convert the AEM voltage to AFR using a simple linear equation. I believe it amounts to: 2 x TGV Volts + 10. I arrived at this using AEM's scaling data provided in their documentation. I haven't had a problem with this approach.

Option 3 doesn't require ATR directly. You can do the conversion in excel but if you plan to use the data to change the map, you'll obviously need ATR.

[Jawhaun]

Originally Posted by ericsson

For anyone thinking about doing this setup.. I did this exact same setup on my '13 STI, and it works great for logging. HOWEVER, I just tried getting a state inspection done this past weekend and my car FAILED because the o2 sensor says is "not ready".

If you live in a state that requires emission testing, this will also happen to you.

Will this also work with the x series gauge?

[GK1707]

Originally Posted by Jawhaun

Will this also work with the x series gauge?

I haven't done this yet, but wouldn't a tuner be able to block the o2 codes and force readiness?

[Jewbaru]

Originally Posted by GK1707

I haven't done this yet, but wouldn't a tuner be able to block the o2 codes and force readiness?

They can block the codes so it doesn't trip the CEL, but they can't force readiness to my knowledge.

[NavyChiefTee]

Sorry to bump an old thread. For 0-5v white wire, is it just getting tapped into the ECU wire, or is the ECU wire totally get cut and getting wired into the gauge 0-5v wire?

Originally Posted by SurfGuruJeff

When I asked Phatron if I could log my AFR with my AP v3, he sent me the link to a kit sold by Moore Performance, but it comes with a relay and extra wiring that you don't need and can't justify spending $85 on. Overkill for just trying to log AFR on your Cobb Accessport. All you need to do is tap your AEM UEGO's 5v output into the correct wire that the ECU would normally use to read off of the Rear O2 sensor (or TGV Left/TGV Right) and then configure the Custom Sensor Input in Accesstuner.

I considered going straight to the harness coming out of the ECU, but opted to go with where I had a little more room while the engine was out which was right at the top of the transmission where there is a connection between two plugs. You may find it easier to tap in at a different location, say, further down the line towards the bottom of the car, or the other direction closer to the firewall.



Plug for the Rear O2 sensor on top of transmission (you may also use TGV Left or TGV Right).


We want the wire that communicates voltage changes from the rear O2 sensor to the ECU, which is the solid white wire on the 2008+ STi (check your year)



Reconnect the plug. *kind of important, haha



I fed the wire through boot for the Right Hand engine harness, then silicone'd over the slit I made. The wire will come through behind the glovebox area.


My AEM UEGO gauge's 12v ACC source is tapped into the radio harness and grounded nearby. The 5v output wire for logging (also conveniently a solid white wire) will connect to the yellow wire that we just routed behind the radio.


Make the necessary changes to your map for AEM UEGO scaling before monitoring. (helpful link from Cobb )


Log/monitor the parameter "Sensor Input Monitor Only (Rear O2)" or "Sens Only Rear O2" on your AP v3



*Note - you can also use TGV Left or TGV Right for monitoring and logging. Just depends on what you want to tap into, and what might make for the easiest access.

**Note - Just another note to anyone installing a AEM X-Series Wideband UEGO with the Bosch LSU 4.9 sensor, you also need to ground the BROWN wire for analog sensor ground. Otherwise it wont output 0-5v to the ecu.

[Jewbaru]

Originally Posted by NavyChiefTee

Sorry to bump an old thread. For 0-5v white wire, is it just getting tapped into the ECU wire, or is the ECU wire totally get cut and getting wired into the gauge 0-5v wire?

It is hard to tell in the pics, but he's cutting the line completely and sending the 0-5v from the WB to the ECU. You can kinda see the cut end of the wire peeking out of the wrap in the pic where the new line is spliced in.

[FrogRacing]

I would not recommend cutting the ECU wire. Just re-use the rear O2 sensor harness and re-route is through the firewall. I made a video showing the install on an 04 STi:

Installing an AEM wideband and logging on a Cobb Accessport - Subaru STI - YouTube

Installing an AEM wideband and logging on a Cobb Accessport - Subaru STI - YouTube

[Alkramlik]

So is this the same for an 04 wrx? If so is the wire color the same? Basically trying to connect the AEM wideband afg to my ap2 for data logging.

[Alkramlik]

Is the wire the same color on 04 wrx? This is extremely helpful

[Lindy19]

Originally Posted by dev6565

They don't allow custom sensor logging on ATR? Since when? I thought that was unlocked after the paid classes went into effect.

Can someone confirm this? I have ATR did the course, but cannot see "Cobb Custom Features" on my table list or "Sensor Inputs"

[Nick 93]

Originally Posted by FrogRacing

I would not recommend cutting the ECU wire. Just re-use the rear O2 sensor harness and re-route is through the firewall. I made a video showing the install on an 04 STi: Installing an AEM wideband and logging on a Cobb Accessport - Subaru STI - YouTube

I'm looking at installing a wideband O2 sensor for e-tuning and had a question after watching your video. If I am planning on installing a controller but no guage, can I just use the power and ground from the rear O2 sensor harness? Again, I'll only be doing this for data logging so I don't really have a need for a guage. Thanks!

[dubs chops]

do you have to have a controller in this scenario or just need to pin the white wire over to the ecm input and give it power and ground?

[JarHarms]

Originally Posted by Nick 93

I'm looking at installing a wideband O2 sensor for e-tuning and had a question after watching your video. If I am planning on installing a controller but no guage, can I just use the power and ground from the rear O2 sensor harness? Again, I'll only be doing this for data logging so I don't really have a need for a gauge. Thanks!

I think that should work as long as it meets the requirements for the lambda controller you are using.

Originally Posted by dubs chops

do you have to have a controller in this scenario or just need to pin the white wire over to the ecm input and give it power and ground?

You cannot just install a lambda sensor probe directly into that ECU circuit if that is what you meant.
Since the ECU does not have an internal controller there needs to be some sort of lambda (WBO2) controller involved and then the analog output from that external controller goes to that "white wire" ECU input circuit. Either is is a separate controller w/o a gauge face [ex. Innovate LC2] or the controller is integrated into a gauge face [ex. AEM UEGO]

[dubs chops]

Originally Posted by JarHarms

I think that should work as long as it meets the requirements for the lambda controller you are using.



You cannot just install a lambda sensor probe directly into that ECU circuit if that is what you meant.
Since the ECU does not have an internal controller there needs to be some sort of lambda (WBO2) controller involved and then the analog output from that external controller goes to that "white wire" ECU input circuit. Either is is a separate controller w/o a gauge face [ex. Innovate LC2] or the controller is integrated into a gauge face [ex. AEM UEGO]

That is what I was thinking. Thanks for the clarification.

[idaeus]

Very helpful thread!

anyone know the best place to ground the brown analog ground wire on an x series AEM gauge? Grounding to chassis is making my readings off on my AP3.

AEM Instructions call for a "sensor ground" but it's not clear exactly where this is. Cant find a description of each wire on sensor harness - tried black but it don't work.

[Nick 93]

I contacted aem when installing mine and they said to use the same ground I tapped into for the black wire. It has worked well for me.

[idaeus]

Thanks Nick 93: to be sure, u mean the black wire on sensor harness? I assumed this was ground, but AEM diagrams don't say....

[IRSLOSTI]

Has anyone done this using the prosport gauges? I have the dual setup (afr/volt) and was wondering if I just tap into the grey output signal and connect it to the rear o2 signal wire?

[dev6565]

I also need help with the brown wire on my AEM X Series. When I connected it with my black ground wire to the exact same ground place as the black wire the gauge stays on 24/7 even when the car is off and key is out. Only way to make it turn off is to remove the fuse tap. I can confirmed that the fuse tap is tapping a circuit that has no power with key out. When I remove the Brown wire from ground the gauge stays off with key out. Doesn't seem right!