EJ22 N/A to EJ22T Swap - Quick MAP Sensor Wiring Question

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Crashsector
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Joined: Sun Oct 14, 2007 2:00 am
Location: Annapolis, MD

EJ22 N/A to EJ22T Swap - Quick MAP Sensor Wiring Question

Post by Crashsector »

Hey all -

I'm swapping a 94 EJ22T into a 91 L using the 91 N/A intake manifold harness. I'm working on wiring the boost-related sensors to the ECU and I only have one question.

I know the three wires for the MAP sensor go to B48.3, 4, and 5, but I can't figure out which one goes where. There is a white, red, and black coming from the sensor. I assume black is ground, but between the white and red which one is power and which one is signal?

Thanks for any help!

P. S.: When I get down to the harness that goes into the ECU (on the N/A car), are there going to be pins in these holes or even wires that I can tap in to? I hope Subaru didn't just leave them empty... then I'm kinda stumped on what to do.

--Andy
2005 Impreza 2.5RS. Traded :(
1991 Legacy L w/1994 EJ22T, 16G, WRX 5MT. Sold :(
1993 Legacy L AWD 5MT, 153k miles and many, many more to go.
2008 Legacy 2.5i Limited
Crashsector
First Gear
Posts: 84
Joined: Sun Oct 14, 2007 2:00 am
Location: Annapolis, MD

Post by Crashsector »

Kinda answered my own question. Found a wiring diagram and from what I can tell this is how it goes:

White - > B48.3 (power)
Black - > B48.4 (signal)
Red - > B48.5 (ground)

Does this sound like I'm going to blow anything up? For the record I'm using page 23 and 24 in the 92 Legacy Engine & Wiring FSM.

Thanks!

--Andy
2005 Impreza 2.5RS. Traded :(
1991 Legacy L w/1994 EJ22T, 16G, WRX 5MT. Sold :(
1993 Legacy L AWD 5MT, 153k miles and many, many more to go.
2008 Legacy 2.5i Limited
beatersubi
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Location: 10-9-oh(!), wa

Post by beatersubi »

That looks correct. If its wired wrong, you won't blow anything up. I confused the pins on the sensor plug when I did my swap and it just ran real crappy until I figured it out.
I suppose you could fry the sensor if you reversed the power and signal wires. Just be sure to refer to plug B131 on pg. 24 of the wiring diagram in the FSM. Or you could check continuity between the ECU side and the pins on the sensor connector.

Oh, and you'll need to add pins to the ECU connector. They're easily 'borrowed' from a spare connector.

You're swapping in a turbo ECU, correct?
93 legacy wagon L, 22T swapped (TW imitator) now with five forward speeds. (Gone, but never forgotten)
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Crashsector
First Gear
Posts: 84
Joined: Sun Oct 14, 2007 2:00 am
Location: Annapolis, MD

Post by Crashsector »

beatersubi wrote:That looks correct. If its wired wrong, you won't blow anything up. I confused the pins on the sensor plug when I did my swap and it just ran real crappy until I figured it out.
I suppose you could fry the sensor if you reversed the power and signal wires. Just be sure to refer to plug B131 on pg. 24 of the wiring diagram in the FSM. Or you could check continuity between the ECU side and the pins on the sensor connector.

Oh, and you'll need to add pins to the ECU connector. They're easily 'borrowed' from a spare connector.

You're swapping in a turbo ECU, correct?
Yep, I am. Just realized today that there are in fact no pins in the ECU connector, so I'm going to have to find someone that hacked theirs off. I should have remembered to get them off of the drivetrain donor... doh!

--Andy
2005 Impreza 2.5RS. Traded :(
1991 Legacy L w/1994 EJ22T, 16G, WRX 5MT. Sold :(
1993 Legacy L AWD 5MT, 153k miles and many, many more to go.
2008 Legacy 2.5i Limited
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