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Speed Density wiring.(IAT)

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Just I case any needs to know, or if any1 is interested in knowing LoL.

When converting to speed density.

The 2x wires that come off the iat sensor need to connect to the old maf sensors 5 pin connector.

I bought a Subaru MALE 5pin connector (ebay) to connect to the old oem female maf connector so there's not any cutting off of wires from the oem loom.

The3x unused ports I filled in with some hot glue. 

I connected it as in pictures below.....

Hope this helps someone. 





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Thanks for the write up , are you able to do this on a stock ECU?

What year /version is this on , so other members can make use of this 👍

When connecting the a ait via the maf wires on my link g4x ECU you have to fit a external pull up resistor. So you usually connect the V1/V2 ait via the link expansion board , so you can select one of the links internal pull ups . As there's no pull ups available on the stock pins for maf on 92 to 95 imprezas afaik .

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In not sure about using this on a standard ecu, but probably yes. 

i m running alcatek impreza ecu in my 2002 51plate forester. 

so this would apply to bugeyes as well I guess. But the wires might be a different colour,but in the same locations in the connector. 


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Did think it might not work on a standard ECU tbh but dont know that much about the later standard ecus. Other than v5 onwards impreza ecus can be remapped with ecutek licenced software or other open source options .

Esl and alcatek boards can be fitted into the the standard ECU cases .link also fit but are a complete replacement plug in ECU.  (So will need a external resistor added inline to use the maf wires )

I'd imagine both esl and alcatek would work without a added external pull up resistor from v3 onwards though .

Thanks for taking the time to show how you used the maf plug to send the ait sensor signal into the ECU.  This will be useful to anyone running esl or alcatek on a v3 onwards, that wants to run mafless and use a ait sensor for intake temperature fuel trims , nice work  👍

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