91 ss power mode

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208ss
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91 ss power mode

Post by 208ss » Thu Apr 20, 2017 3:55 am

So im wanting to do the power mode mod on my 1991 legacy ss. But i have read that I cant because the pin 4 goes to the cruse control. I'm wanting to know if i get a tcu from a 92-94 na legacy would my connectors fit into it? or would i need to get the whole wiring harness from said car to make it work.
or If some one has made the power mode mod to work on a 91 tcu please chime in/
1991 subaru legacy sport sedan

Legacy777
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Re: 91 ss power mode

Post by Legacy777 » Thu Apr 20, 2017 5:49 pm

From looking at the wiring diagrams it looks like that pin 4 to the cruise control is different and there's a pin B46 pin 15 that is on the 90-91 cars related to the speed sensor 2 and it's not there on the 92 wiring diagrams. In theory I think you could run the 92 TCU, however I'm not sure if the transmission would like the non-turbo TCU. You'd need to snip that wire at pin 4 so it doesn't interfere with the cruise (your cruise control may not work), and you'd probably want to look into whether your car has the pin for the speed sensor 2.
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
1997 Impreza OBS

If you need to get a hold of me please email me rather then pm

208ss
First Gear
Posts: 100
Joined: Wed Jan 01, 2014 7:04 pm
Location: boise. id

Re: 91 ss power mode

Post by 208ss » Sun Apr 23, 2017 11:42 pm

Do you have the different diagrams for the 91 and 92-94 tcm that you could share?
1991 subaru legacy sport sedan

Legacy777
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Re: 91 ss power mode

Post by Legacy777 » Mon Apr 24, 2017 5:50 pm

These are from the 90 MY, but should be applicable to the 91. I'd have to double check when I get home.

http://main.experiencetherave.com/subar ... _page1.jpg
http://main.experiencetherave.com/subar ... _page2.jpg


Similarly I'll have to check the 92-94 when I get home.
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
1997 Impreza OBS

If you need to get a hold of me please email me rather then pm

Legacy777
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Re: 91 ss power mode

Post by Legacy777 » Tue Apr 25, 2017 3:32 am

The 90 & 91 TCU I/O is identical.

The only differences I saw was the 92-94 TCU I/O notes the atmospheric pressure sensor input is for non-turbo only.

The other thing I found was that the 90-91 TCU I/O has the brake switch labeled incorrectly. The 92-94 TCU I/O is correct and that's how the 90-91 is wired as well....the FSM is just wrong. You can check the individual wiring diagrams and they match vs. what the I/O lists.

So just use this scan

http://main.experiencetherave.com/subar ... CU_I-O.pdf
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
1997 Impreza OBS

If you need to get a hold of me please email me rather then pm

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