AEM Gauge Wiring Question

I bought a set of AEM Gauges for my 2005 Subaru outback xt. I got AFR, Oil Pressure, and EGT. I know how to wire power to the gauges, what I don't know is how to wire the 0-5V analog wiring to the ECU so that I can data log. I really only care to have the AFR gauge wired to the ECU, but if it is easy enough I might as well do the other ones too. Hopefully, someone has some experience with this and knows where to splice in the wires.

The AFR gauge is an AEM 30-0300 X series gauge BTW.

 

Here are the Instructions:

https://www.aemelectronics.com/files/instructions/30-0300.pdf

https://legacygt.com/forums/showthread.php/logging-wideband-through-egt-input-280648.html

 

I did the same thing with the AFR guage awhile back. The two common ways to route it into the ecu is through the rear O2 or TGV. You can do it through the MAF but you would have to transition to speed density. I went with the rear O2. I just had to disable the rear O2 learning and splice the signal from the guage to the blue wire of the rear O2 loom. The hardest part is to get the raw voltage value to produce and accurate reading of the current AFR while logging.

 

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I have AFR and Oil Pressure wired through the TGVs, because I had deleted them and freed up their 0-5v feeds.

I have AFR and Oil Pressure wired through the TGVs, because I had deleted them and freed up their 0-5v feeds.

 

So I also have my tgvs deleted, so do I just need to find the power wire to splice in?

If I do tgvs what parameter would I be looking for to read afr, would it be tgv related?

The easiest way is to use the matching 3-pin plug from iWire: https://www.iwireservices.com/3-pin-plugs

 

There will be power, signal, and ground.

 

I used a number of resources, this is one of them:

https://legacygt.com/forums/showpost.php?p=5725259&postcount=57

 

This is a good one as well, just need to be careful that you filter out what's applicable to you:

https://legacygt.com/forums/showthread.php/logging-wideband-o2-via-tgv-sensor-input-243134.html

 

Don't just run with the first bit of info you find, keep digging (you may do this already, I'm bad at trying to aha at the first thing that looks like it lines up).

 

Not sure what you are using for logging, I've been using Btssm.

When setting up BtSsm the address is 000034 for left (driver side) tgv input, or 000033 for right (passenger side) tgv input.

 

Highly recommend a lot of searching and reading before doing this.

I think for the oil pressure, it was all off the TGV (power/signal/ground), but for the Wideband I only used signal in the TGV plug, ground is to the chassis, and power is tapped from the harness on the eng/tranny because I wanted power only when running.

Something about longevity, looking for the reference.

I'm using romraider for a data logger, I'll look and see if I can find a parameter related to the tgvs when I get off work.

 

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I'm using romraider for a data logger, I'll look and see if I can find a parameter related to the tgvs when I get off work.

 

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You should be able to find them as P39 and P40

 

<parameter id="P39" name="Tumble Valve Position Sensor Right" desc="P39" ecubyteindex="12" ecubit="0" target="1">
<address>0x000033</address>
<conversions>
 <conversion units="V" expr="x/50" format="0.00" />
</conversions>
</parameter>

 

<parameter id="P40" name="Tumble Valve Position Sensor Left" desc="P40" ecubyteindex="13" ecubit="7" target="1">
<address>0x000034</address>
<conversions>
 <conversion units="V" expr="x/50" format="0.00" />
</conversions>
</parameter>

Edited June 19, 2020 by Infosecdad

So I found the parameters you quoted in the logger definitions. If I'm understanding this correctly I am supposed to replace those sections of code with the new code written for afr?

 

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Yes, you would need to replace the formula "x/50" in the expr with one for your sensor(s).

Cool, this seems easier than I thought it would be. I have another question now, so I'll log my oil pressure and afr through my tgv wiring. I also deleted my oem egt sensor but I have the new aem one in a different location, can I use the wiring from the factory egt to log readings from the new egt?

 

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So I got those connectors and I'm trying to wire up my guages. I can't seem to find any information on which wire on the connector is signal positive and which is signal ground. There is a black wire with a blue stripe, a black wire with a yellow stripe in the middle and a yellow wire with a red stripe. Does anyone know which wires are which? It looks like the yellow wire with the red stripe is the signal positive. You can see in the diagram it goes to the ecu. I still don't know if black and blue is signal ground, or if it is black and yellow. Ive traced those wires through the wiring diagram and can't figure out which is which.

 

 

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Edited June 28, 2020 by samuel082799

I'm pretty sure the middle (Black/Yellow) is ground and the Black/Blue is 12v power.

I'm trying to find my notes for it.

 

You can confirm with a voltmeter, should be able to turn the key to ACC and get a 12v signal from one of them. The other should have continuity to ground.

BL-5V power from ECU pin C16

BY-ECU ground

RY/WR-ECU signal to ECU pins 26 and 27

From what I've read, you can power an oil pressure sensor from this; but for the WB, you need a bigger power source. I pulled it off the harness that runs down the transmission.

From what I've read, you can power an oil pressure sensor from this; but for the WB, you need a bigger power source. I pulled it off the harness that runs down the transmission.

I think I'm just going to use a fuse tap tied into all my guages for the power. Fuse taps have worked good for me in the past.

 

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I'm pretty sure the middle (Black/Yellow) is ground and the Black/Blue is 12v power.

I'm trying to find my notes for it.

 

You can confirm with a voltmeter, should be able to turn the key to ACC and get a 12v signal from one of them. The other should have continuity to ground.

 

BL-5V power from ECU pin C16

BY-ECU ground

RY/WR-ECU signal to ECU pins 26 and 27

 

I hope everyone is doing well. I just wanted to make sure that I'm reading this correctly. If any of you who have done this would please help confirm this it would be greatly appreciated. I'm currently working on wiring in my own DIY fuel pressure sensor that will plug into my 3 pin tgv connector plug. I have two harnesses because I'm using an amazon transducer that came with the wiring harness. I wasn't feeling the wire thickness from the provided harness. I decided to pick up the autometer wiring harness.

 

Based on all of the research I've done I think this is what I've concluded as the proper way of wiring this sensor in. Any assistance with this is very much welcomed.

 

Original wiring information from the original post: https://forums.nasioc.com/forums/showthread.php?t=2878019

 

Autometer #5227 harness wiring colors:

Black - Ground

Violet - 5v Signal

Grey - 5v Reference

 

Subaru TGV = Autometer wiring

Black/Blue = Gray - 5v Reference / 5V Input

Black/Yellow = Black - Ground

Yellow / Red = Violet - 5v Signal or Output 0.5 – 4.5V

 

 

 

Subaru TGV = Amazon Transducer

Black/Blue = Red - 5v Reference or 5V Input

Black/Yellow = Black - Ground

Yellow / Red = Green - 5v Signal or Output 0.5 – 4.5V

 

Original Thread: https://legacygt.com/forums/showthread.php/logging-wideband-o2-via-tgv-sensor-input-243134p8.html

 

http://i.imgur.com/X73rGYf.jpg

Edited December 21, 2021 by k00laid83

Sorry for bumping an old post. Did anyone tried to wire a 2 wire temp sender to the tgv feed before?

Sorry for bumping an old post. Did anyone tried to wire a 2 wire temp sender to the tgv feed before?

To my knowledge you should be able to wire anything into a tgv as long as one of the wires is a signal wire.

 

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If the temp sender sends a signal that's 0-5v, then it should work; just need to find the formula to convert the voltage to the measurement for temp.