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.

7.35 for a low AFR? holy cow

Hahaha. Yeah. Borrowed pic from Moore Performance.

Just did this recently also. Did mine plug and play with a o2 sensor plug like this one:

http://www.bmotorsports.com/shop/pro...oducts_id/3242

and if anyone wants to buy just a pig tail, i believe you can get one pre wired from moto-east. worth it to note this will only work with a protuner. Im pretty sure ATR does not have custom sensor logging enabled.

So connect white aem 0-5v to o2 sensor side of pigtail.
What about the blue serial output aem wire, not needed?

Most importantly, can you hook up egt, oil temp, diff temp, and oil pressure in a similar way?

Correct, the blue serial wire is not needed.

Yes, you should be able to wire up similar sensors, then configure in AccessTuner

How about Onboard realtime map switching?


http://forums.nasioc.com/forums/show....php?t=2776027

This is what I plan on doing with my WMI. nice.

It works fantastic.

I was testing it all out-in boost on the meth maps, trigger the fail safe, it's instant switch over to my pump maps-looking at data logs the boost drops right down from my meth level to pump level & it's really smooth.

No need to let off the throttle, just keep on keeping on.

The thing that has me most excited is now having two timing/boost maps.

This is huge-finally I can run nitrous without a stand alone ecu.

That's what's prevented me on this car. I'm just waiting on a built block to put it all together. Had it all on my last turbo car & I miss it dearly, it's a great void in my life.

Soon, soon...

sick. I guess you just used the same wiring as the flex fuel install but with the meth signals instead?

Yeah, left or right tgv input, 5v or 0v to switch. I tied in at the ecu wiring harness. It's all in the aquamist thread around page 75 maybe?

Seems like this could be used for the torque app too unless I'm missing something.

So this only works for 08+? I have an 05 sti

^^Curious too 02 WRX

Should work for most years, but you'll have to find the correct color wire (it is different) for your '05 to tap into.

Looked today. Plug and wires are same for 02 WRX.

Wish these features were available in ATR. But I may hook up a redundant pigtail so I can keep it hooked up to the OEM harness for now and easily switch to the second pigtail with the UEGO input next time I do more with my e-tuner.

I believe the new ATR does have custom sensor logging enabled.

Hmmm, checked my ATR for updates and found none. Is this a new version thats needs a separate download?

yes the newest version that requires a class.

Ah I guess that'd be why. Thanks.

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.

Thanks for that. I'll update first post.

How can I use the custom logging with my car? Anytime I try to connect it says my ecu is invalid

Just did this in my 07 STi, worked like a charm I don't have the new fancy version of ATR so I just log the AFsensor 3 voltage and convert it in excel.

Was able to start open loop maf scaling today, once that's dialed in I'll pull a little fuel out of the cobb map

does this affect to way the rear O2 functions? If hooking up to TGV wire i take it they have to be deleted?
I'm thinking you would be able to log wideband with btSsm.