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Old 04-20-2020, 02:24 AM   #101
JSR84
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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.
Sensor Ground is the grounding point the ECM references ground for all the sensors. It's done like this to ensure the sensors have a common reference to ground and eliminate any potential voltage offset. You can locate the sensor ground wire in the Factory Service Manual.
The pin outs differ from year to year so ensure you have the correct FSM. On my 09 STi the Rear O2 sensor ground was a Yellow and Green wire on ECM connector B135 pin 30. The Rear O2 signal was a white wire, on ECM connector B135 pin 4. If you connect them a few inches down from the connector it saves you from having to punch wire through the firewall.

I originally used the same grounding location as the I had the controller ground but I had an offset between the AP and the gauge reading. Once I switched to sensor ground the offset was gone. I definitely recommend using sensor ground if your wideband's analog output has a ground wire.
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Old 04-21-2020, 01:12 AM   #102
badaily16
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I'm currently doing the wiring in my 06 sti. I have the aem side wiring done and was taking apart my rear o2 sensor wires and noticed the blue and white wires are linked into each other for some reason. Looks like it was from one of the previous owners. Is this a concern or should I go ahead and continue with the install? Any help is appreciated.
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Old 04-21-2020, 11:22 AM   #103
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Quote:
Originally Posted by JSR84 View Post
Sensor Ground is the grounding point the ECM references ground for all the sensors. It's done like this to ensure the sensors have a common reference to ground and eliminate any potential voltage offset. You can locate the sensor ground wire in the Factory Service Manual.
The pin outs differ from year to year so ensure you have the correct FSM. On my 09 STi the Rear O2 sensor ground was a Yellow and Green wire on ECM connector B135 pin 30. The Rear O2 signal was a white wire, on ECM connector B135 pin 4. If you connect them a few inches down from the connector it saves you from having to punch wire through the firewall.

I originally used the same grounding location as the I had the controller ground but I had an offset between the AP and the gauge reading. Once I switched to sensor ground the offset was gone. I definitely recommend using sensor ground if your wideband's analog output has a ground wire.
JSR84, Thanks for the additional background on this topic, I’m going to look at to it more using this because I still have not solved the problem.
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Old 04-28-2020, 09:01 PM   #104
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Has anyone successfully done this with a 04 wrx? Im pretty sure I have everything wired up correctly but once the sensor gets heated my Voltage on the AP pegs at 1.25V is this something that needs to be changed with ATR?

Last edited by Sniperx9119; 04-29-2020 at 06:42 AM.
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Old 08-13-2020, 09:20 PM   #105
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does anyone know how to have AFR reading on Acessport instead of Voltage. I've rescaled the parameter on Cobb AT already. I'm confused, don't know what I did wrong.


Thank you.
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Old 09-10-2020, 01:54 PM   #106
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Is it worth the extra money to just buy the iwire kit?
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Old 09-10-2020, 03:00 PM   #107
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Its pretty easy to do without needing a kit..
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Old 09-10-2020, 03:03 PM   #108
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Its pretty easy to do without needing a kit..
Will the Visconti cable help? Going to get new shortblock I’m so whatever is cleanest and easiest. I will be doing tgv and getting flex fuel if that matters?
I also see the spartan kit with sensor for 125 it can get viscount for half off and just get the sensor for 90? Or would I need the uego controller?

Last edited by splitoris; 09-10-2020 at 07:15 PM.
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Old 10-11-2020, 11:18 AM   #109
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I just installed the ProSport AFR gauge, which included the Bosche LSU 4.9 sensor, and the AEM UEGO controller box. This is on my 2006 STi.

Having a strange problem and cannot figure out what the underlying cause is. The gauge and sensor work well, but when the analogue output is connected to the rear o2 signal wire, it causes the gauge reading to drop to 10-10.3 AFR, and the accessport shows 0-0.06 volts for the rear o2. I have tried using the ground from the rear o2 for the analogue output ground as well as using the same ground as the gauge uses. I have the OEM rear o2 removed and have the Bosche sensor there right now (might change that later to be further upstream on the exhaust for better synchronization).

I thought maybe it was a power issue. I originally had the unit powered by the same wires that the other gauges in the car are powered by (installed by previous owner, think they might connect to the clock) and I instead tapped into the radio's power, ground, and ignition. No change in behaviour after doing that.

My next thing to try is going to be buying a fuse tap and tapping a fuse that is not used.

The thing I find odd about this is that I would expect the analogue output's connection not to have a feedback loop that in turn impacts the output that goes to the gauge.

Has anyone had similar issues?


Edit: Figured out the issue. If the rear o2 sensor is unplugged completely (as mine was since I replaced it with the wideband sensor) then it will behave this way. I plugged in the original rear o2 to the connector on top of the transmission and then rerouted the sensor signal to come from the wideband and then split the ground to go to the wideband as well as the original sensor. That got everything running as expected.

Last edited by tabrad; 10-11-2020 at 03:26 PM.
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Old 10-30-2020, 01:29 AM   #110
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Default Will this work with cobb flex fuel kit?

I have a 2018 sti, stage 3, and cobb flex fuel kit. I know the FF kit is plugged into the rear o2 sensor I believe, do i still just use the white wire as stated? Anyone else tried this with cobb FF kit?
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Old 10-31-2020, 03:42 PM   #111
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If the flex fuel kit is only pulling the power from the rear o2 sensor, then yes you can proceed using the same white wire that everyone else is. I would just make sure that the flex fuel kit is not using that white wire.
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Old 11-11-2020, 10:47 PM   #112
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If the flex fuel kit is only pulling the power from the rear o2 sensor, then yes you can proceed using the same white wire that everyone else is. I would just make sure that the flex fuel kit is not using that white wire.
Thanks, I have it hooked up. Car seems to run well. I installed an iag aos separator at the same time as connecting my aem afr to my accessport. Now though, when I pull up the rear o2 sensor monitor, i see like 3.3 on idle, on start up it maxes out to 7.4 for a second.....I'm not reading afr tho....but that 7 doesnt make me think I'm just reading 1-5v either lol. Is there something my tuner needs to do?
The car is a 2018 sti. Stage 3 w/ flex fuel.
Thanks again.
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Old 11-22-2020, 02:44 PM   #113
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Very helpful thread, thanks guys. I'm a newb when it comes to wiring and looked through the FSM but still have questions. Basically, I'm doing a few mods to my 2011 STI in a few weeks and want to be prepared.

I've got a bunch of parts including an AEM AFR gauge on the way and want to connect the analog output to my TGV RH harness. I went ahead and got the iWire "connector kit" TGV plug here



In the FSM, it appears pins 4 and 5 on the TGV RH plug are the voltage output. Pin 4's wire is pink with blue and leads to B25 on the ECM for "TGV RH closed" while pin 5's wire is white with blue and leads to B26 for "TGV RH open". That is if I'm reading the color codes correctly and PL = pink with blue stripe and WL = white with blue stripe.

Here is my RH TGV plug currently:

I want to log the AFR with my Cobb AP. I am guessing I want to connect the white output from the AEM AFR gauge into pin 5 - white with blue stripe, which should correspond to TGV open. In Cobb AccessTuner I will overwrite the "TGV closed" tables with the data from TGV open tables. And of course disable all of the CELs.

Then there is the brown ground wire on the AEM gauge, which I see should be grounded into the "sensor ground", not just a chassis ground. Would that be the black wire in pin 2 on the TGV RH plug? I tried to find a sensor ground in the FSM but it only gives 9 results, all from the diagnostic section, none from the diagrams. Like I said, I'm a dumdum when it comes to wiring so I'm just looking for some help before I dive in.

If you're curious about my project, I've only had this STI for a few months. It has 45k miles, 3k on a stage 2 IAG shortblock. The dyno-tune it has is giving some decently high feedback knock values in the 3200 - 4000 RPM range with modest throttle position (30%) that I want to tune out, but the tune is locked and I can't edit it. The tune was done before the new shortblock, UEL headers, and turbo inlet upgrades. The car has quite a few mods but none to the turbo or fuel system (sans a small Tomei regulator & gauge). I semi-deleted the air pump but got block-off plates to finish that job. Also doing a DIY TGV delete + powder coat, phenolic spacers, AFR gauge install to self-tune, 4th cylinder cooling mod, and adding a catch can to the GrimmSpeed AOS that was on the car when I bought it and I'm too cheap to drop $400 on a new, proper AOS. We'll see if this eBay catch-can does the trick. I'm really curious to see how much oil I have in my inlet and TMIC, as I've heard this GrimmSpeed AOS is pretty much garbage (and I see some oil in the line leading back to the intake). I'm also replacing gear oil & rear diff with Motul 300 since the previous owner did autoX races but never changed the transmission or rear diff oil. I do have a 5th gear grind at high RPM, so I'm hoping new Motul will help that.

Thanks in advance for anyone that can help me with this wiring!

Last edited by snake2332; 11-22-2020 at 03:07 PM.
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Old 11-22-2020, 08:09 PM   #114
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First it's pretty dangerous to run with out a proper tune for the block. Second yes all tunners worth there salt, lock there tunes it keeps people honest.
Third the first line of business should be to get a proper tune for the setup. Whether it you yourself or etune something needs to be done now.

As for the ground wire , I've seen it both way i think grounded to though the harnesses and though the body.
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Old 11-22-2020, 08:15 PM   #115
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Quote:
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The tune was done before the new shortblock, UEL headers, and turbo inlet upgrades. .

Thanks in advance for anyone that can help me !
You need to get a tune. You're welcome.
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Old 11-22-2020, 09:56 PM   #116
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Ya I'm going to get an e-tune since there aren't any dyno tuners near me afaik. I'm going to compare that with my own tune based off the Cobb OTS stage 2+ since I want to get into tuning more. I understand the risks. I'm going to set timing to where there is no knock, then get my AFR to be flat 11.3 - 11.5, then play with timing carefully. I'm getting the map set up now for TGV + airpump delete before I do that actual mods. Don't worry, I'll be watching knock and AFR like a hawk and not doing any WOT pulls until it's safe. I'm on stock injectors and turbo, so we're only talking 300whp/330wtq. Man I wish we had E85 or even 93 octane around here...
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Old 11-23-2020, 02:31 PM   #117
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I might hold off with the TGV delete until I can buy injectors and fuel pump upgrades. My IDC is already hitting 92%+ and with 91 octane fuel I should keep AFR around 11.0. My injectors probably can't keep up with more airflow while maintaining a safe, rich AFR, so the TGV delete would be pretty pointless other than I could probably run less boost.

However, I will still briefly hook up the analog output of the AEM AFR gauge and update this thread with which wires worked to tap into.
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Old 11-23-2020, 06:00 PM   #118
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Sounds good, look around for some used id1000s they'll get you started and arm fuel pump. You can get those pretty cheap.

Check out Hp academy on YouTube free tunning webinar should get you where you need to be. Your MAF scaling is most definitely off as Staged blocks are a bit lager. Your going to have to scale the injectors too

Mega logviewer seems to be the go to and you can pull your rear 02 afr data into a laptop for now. Btw iD keeps there injector scaling data on there website
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Old 11-23-2020, 06:11 PM   #119
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Yep that's what I was looking at exactly, the ID1050x and AEM 340, and I've done the Cobb training to unlock AccessTuner and read a lot and watched as many videos as I can find including all of #SteveTuned channel (I recommend it, not really to learn tuning per se).
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Old 11-23-2020, 09:37 PM   #120
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Why worry about the rear O2 just yet the front will get you where you need to be. Where did you start tuning at. You just messed with the timing. I figured you unlock ATR when you set the tunes were locked. Its probably going to be hard to scale the injectors correctly unless you have the data on them.
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Old 11-23-2020, 10:10 PM   #121
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Originally Posted by zeno15STI View Post
Sounds good, look around for some used id1000s they'll get you started and arm fuel pump. You can get those pretty cheap.

Check out Hp academy on YouTube free tunning webinar should get you where you need to be. Your MAF scaling is most definitely off as Staged blocks are a bit lager. Your going to have to scale the injectors too

Mega logviewer seems to be the go to and you can pull your rear 02 afr data into a laptop for now. Btw iD keeps there injector scaling data on there website
How does the bore matter when it comes to the MAF scale?
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Old 11-24-2020, 10:48 AM   #122
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My MAF scaling is still accurate. I have the Cobb SF and MAF scaling is set appropriately. New shortblock wouldn't affect that.

And yes I know about injector scaling and latency tables. I found some DW 1200's for $400 that I'm contemplating, and would throw in an AEM fuel pump with those. I would love to upgrade the fuel rails, lines, and regulator but damn that isn't cheap ($800+) so I doubt I'll get that done while I have the intake manifold off, sadly. I currently have a type-s Tomei FPR but just standard fuel lines and OEM rails.

My stage 2 IAG shortblock has OEM specs for everything, just with upgraded rods, bearings, and pistons, so it might not necessarily warrant a tune but the headers and turbo inlet do.

I want to see the rear O2 data mostly because I don't trust the front one enough and it only reads down to 11.03, so I don't know how rich the mixture really is. At WOT it just logs a straight 11.03 through the whole range. I want to see detail below 11 and further down the exhaust. I got the AFR gauge delivered yesterday but have too many non-car tasks to do in the next couple weeks to dive in, so maybe over xmas break I'll get some stuff done and have something useful to add to this thread.
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Old 11-24-2020, 11:56 AM   #123
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My MAF scaling is still accurate. I have the Cobb SF and MAF scaling is set appropriately. New shortblock wouldn't affect that.

And yes I know about injector scaling and latency tables. I found some DW 1200's for $400 that I'm contemplating, and would throw in an AEM fuel pump with those. I would love to upgrade the fuel rails, lines, and regulator but damn that isn't cheap ($800+) so I doubt I'll get that done while I have the intake manifold off, sadly. I currently have a type-s Tomei FPR but just standard fuel lines and OEM rails.

My stage 2 IAG shortblock has OEM specs for everything, just with upgraded rods, bearings, and pistons, so it might not necessarily warrant a tune but the headers and turbo inlet do.

I want to see the rear O2 data mostly because I don't trust the front one enough and it only reads down to 11.03, so I don't know how rich the mixture really is. At WOT it just logs a straight 11.03 through the whole range. I want to see detail below 11 and further down the exhaust. I got the AFR gauge delivered yesterday but have too many non-car tasks to do in the next couple weeks to dive in, so maybe over xmas break I'll get some stuff done and have something useful to add to this thread.
I would really recommend you stay away from DW injectors. They're data is generally not that accurate. Injector Dynamics have a great reputation for consistency and good data. Fuel Injector Clinic is another brand I hear good things about. Even still, its always advisable to confirm the injector scaling and latency, and having an accurate wideband is a must. Also, you must have a correctly scaled MAF / VE Table, trying to scale injectors off a MAF that's not correctly scaled is a crap shoot. I highly recommend you use a sensor ground, I was able to find the correct pin in the FSM for my 09. I made a post about it in this thread. The reason being is because the grounding location can and will cause a deviation between the wideband controller reading and the ECU input, I found it to be about 2 percent off using a chassis ground vs a sensor ground. Not a huge amount, however its something you can control and it helps to have accurate data when tuning.
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Old 11-24-2020, 12:42 PM   #124
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I would really recommend you stay away from DW injectors. They're data is generally not that accurate. Injector Dynamics have a great reputation for consistency and good data. Fuel Injector Clinic is another brand I hear good things about. Even still, its always advisable to confirm the injector scaling and latency, and having an accurate wideband is a must. Also, you must have a correctly scaled MAF / VE Table, trying to scale injectors off a MAF that's not correctly scaled is a crap shoot. I highly recommend you use a sensor ground, I was able to find the correct pin in the FSM for my 09. I made a post about it in this thread. The reason being is because the grounding location can and will cause a deviation between the wideband controller reading and the ECU input, I found it to be about 2 percent off using a chassis ground vs a sensor ground. Not a huge amount, however its something you can control and it helps to have accurate data when tuning.
Yeah I heard that too, but couldn't find good examples of their issues. I definitely was staying away from their fuel pumps. I think I will spend the extra $120 to get ID1050's instead.

And yeah I looked in the FSM and am still unsure of where a good signal/sensor ground is to use, mostly because I'm bad with electrical diagrams but also because it doesn't seem to specifically say in plain english. That's why I was asking about the wires on the TGV plug. Like, which pin in this diagram, or am I even looking in the right section? I was guessing pin 2 which is a black wire, which makes sense to me but I don't know.
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Old 11-24-2020, 12:49 PM   #125
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Yeah I heard that too, but couldn't find good examples of their issues. I definitely was staying away from their fuel pumps. I think I will spend the extra $120 to get ID1050's instead.

And yeah I looked in the FSM and am still unsure of where a good signal/sensor ground is to use, mostly because I'm bad with electrical diagrams but also because it doesn't seem to specifically say in plain english. That's why I was asking about the wires on the TGV plug. Like, which pin in this diagram, or am I even looking in the right section? I was guessing pin 2 which is a black wire, which makes sense to me but I don't know.
Find the section that shows the ECU pin out.
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