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Name those MAF wires!


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What does each wire do?

 

http://i193.photobucket.com/albums/z151/Legacy_NSFW/Intake/MAF.jpg

 

From left to right they are... what? Power and ground should be easy enough, it's really the other three that I wonder about.

 

I ask because I want to feed the MAF signal into a now-unused 0-5v input that used to be connected to a TGV position sensor. I just installed a blow-through MAF sensor, and logging MAF from both the existing and new sensors should make it very easy to get the new MAF scaling correct (or at least, close) on the first try.

 

Logging both at once should also prove or disprove a theory about FMICs, lag, and a rich dip that generally occurs right after spoolup on Subarus with big intercoolers.

 

So again, from left to right they are... what?

 

Thanks in advance!

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You will have to tell us the model year, it is a little different on the 05-06 versus the later ones. I have the diagrams in front of me right now.

 

EDIT: these diagrams are confusing, they don't match up to the colors and pinout in the FSM completely. Maybe your pic is affecting the way the colors look.

 

The middle wire is definitely MAF signal, the black/green to the right of it is MAF ground, but the other stuff is confusing because the colors don't match the pinout. In the connector pinout Subaru numbers each pin and then you have to match it to the color in the diagram. But the connector pinout, the diagram, and your pic don't match. Other manufacturers have a connector pinout with actual wire colors so it's easier to match something... Subaru is very frustrating. And then Subaru will have a wire going to another page, but they don't label what the page is (what system it's for), they just give the page number, so you have to go chase it down and figure it out.

 

You're going to have to meter the wires to be sure. On the 05 there is power, MAF signal, MAF ground, IAT signal, and then IAT ground which is shared with the water temp sensor back near the ECU. Also note that the MAF signal wire is shielded. It is tied with the shield wire coming from pin 32 on that same B136 ECU connector.

 

See page WI-40 in the 05 FSM and WI-65 in the 08 FSM

Edited by Boostin
On the search for a new DD...
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Thanks guys.

 

I hooked up a voltmeter to the MAF plug and found:

 

1 = ground

2 = + 4.76v

3 = ?

4 = ?

5 = + 12v

 

Presumably 3 and 4 are MAF and IAT, or vice-versa. I'm going to make a wiring harness extension to sniff those signals. I meant to stop by an electronics place and pick up some mini spade connectors that I think will work well for the flat 'pins' on the MAF sensor, but forgot to, so that will have to wait. If 3 is the shielded one (as per the FSM), that would suggest that's the MAF signal.

 

And on the TGV position sensor connector:

 

1 = +5.00 v

2 = ground

3 = signal

 

With a 1M-ohm pot attached to the TGV position sensor I was able to get a logger to read varying voltages on for the TGV position parameter.

 

I find it a little strange that the TGV sensor gets 5.0v from the wiring harness and the MAF/IAT gets 4.76v. :confused: Anyone got thoughts on that?

 

My car is an 05, by the way.

Edited by NSFW
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1. Power (Yellow/Blue)

2. Ground (Black/Green)

3. MAF Signal (Red/Blue)

4. Temp Signal (Yellow/Blue)

5. Ground (Yellow/Green)

 

This listing is from right to left for your picture.

Edited by dschultz
added colours
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or you can make your own set for a fraction of the cost of something with a brand name label on it

 

 

Maybe, but are you going to get the circular flow of current like you will with the HKS? These are all very important points to consider You shouldn't put a price on the well being of your car.

OBAMA......One Big Ass Mistake America!
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I think you have some bad engine grounds :lol:

 

I don't think so, the +12 at the MAF connector read the same as +12 at the battery terminals. It was actually a bit less than 12, I think I killed another battery. :)

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Maybe, but are you going to get the circular flow of current like you will with the HKS? These are all very important points to consider You shouldn't put a price on the well being of your car.

 

You really can't beat a circular flow of ground current.

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Time to hit all your grounds with a voltmeter. I did it and it solved my 3 month ongoing tps limp mode issue with my car after I tore apart my entire dash and replaced my ecu.
06 TB EVO IX SE stock turbo monster subaru hater :lol:
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My sons old 92 Legacy L wagon had weird ECU problems and sensors giving crazy readings. It ended up being dirty grounds. Cleaned them up and everything went away like magic. Its amazing what a little voltage drop will do.
BE committed to DO what it takes to HAVE more of what you want in your life!!!
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Maybe, but are you going to get the circular flow of current like you will with the HKS? These are all very important points to consider You shouldn't put a price on the well being of your car.

 

 

That is funny...I got a bridge for sale, interested?

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Are you going to use one TGV input for your new MAF and the other for it's temperature sensor? Am I wrong to assume that your new MAF position would be subjected to different temperatures than the ECU is accustom to and needs.
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I was planning to just log the MAFv from the new sensor, to make it easier to get the MAF scaling set up. Plus I think it would be cool to make a graph that demonstrates that the "FMIC rich dip" really does come from a difference in MAF as measured at each location (or not, as the case may be).

 

I think that the new sensor's IAT will be in the same range that the ECU is accustomed to. The turbo will heat it up, the IC will cool it down, but temperatures from my CAI go up a bit during a pull too. I dunno how it will end up, but I am curious.

 

After I switch to blow-through I do like the idea of using the TGV sensors for pre- and post-turbo IAT just to see if I can reverse-engineer the compressor map with a spreadsheet. That's not a super high priority but it might happen.

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After I switch to blow-through I do like the idea of using the TGV sensors for pre- and post-turbo IAT just to see if I can reverse-engineer the compressor map with a spreadsheet. That's not a super high priority but it might happen.

 

I love this idea and might have to use it one day, but for now just like you it's on the end of a long list.

[CENTER][B][I] Front Limited Slip Racing Differentials for the 5EAT now available for $1895 shipped, please inquire for details! [/I][/B][/CENTER]
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  • 5 years later...
This listing is from right to left for your picture.

 

1. Power (Yellow/Blue)

2. Ground (Black/Green)

3. MAF Signal (Red/Blue)

4. Temp Signal (Yellow/Blue)

5. Ground (Yellow/Green)

 

http://i193.photobucket.com/albums/z151/Legacy_NSFW/Intake/MAF.jpg

 

Sorry to reopen an old thread but I found it through a Google Search because I am using a Suby MAF Sensor for my Nissan Altima Turbo.

 

Are these listing the same for the 2012+ Imprezas? And are the MAF sensors the same between the STi and WRX's? I bought a 2012 STi MAF Sens0r :icon_conf

Edited by BMW530i
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'08+ STI got a new style MAF sensor that has a slightly higher threshold. You should be able to see the P/N molded right on the face of it.

 

Thank you but that doesnt quit answer my question. I gather that the STi uses a different MAF sensor than the WRX? And are the pinouts still the same as the picture? The metal ears are reversed (180degrees) on the sensor that I have.

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On the '08+ STI MAF (P/N 22680AA380) the pin-out is as follows (looking into the connector on the MAF side, with the retaining tab up, left to right).

 

1. Temp Signal

2. Ground

3. Power

4. Ground

5. MAF Signal

 

Not only are the mounting ears mirrored - the shoulder with the o-ring groove is a larger diameter on the '08+ STI MAF, and cannot be installed in '05-'09 LGT/OBXT housings.

Edited by Underdog
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On the '08+ STI MAF (P/N 22680AA380) the pin-out is as follows (looking into the connector on the MAF side, with the retaining tab up, left to right).

 

1. Temp Signal

2. Ground

3. Power

4. Ground

5. MAF Signal

 

Not only are the mounting ears mirrored - the shoulder with the o-ring groove is a larger diameter on the '08+ STI MAF, and cannot be installed in '05-'09 LGT/OBXT housings.

 

Thank You! I'm not using it on a Subaru though. I'm using it on a Nissan Altima Turbo project. Everything is installed but the stock Nissan MAF is teh suck.

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