Results 1 to 23 of 23

Thread: 97 AT->MT swap, ECU question

  1. #1
    Needs to update their Email!
    Join Date
    Aug 2007
    Location
    Old Boston, PA
    Posts
    173
    Points
    5,901
    Level
    49
    Points: 5,901, Level: 49
    Level completed: 76%, Points required for next Level: 49
    Achievements:
    5000 Experience PointsO.G.

    97 AT->MT swap, ECU question

    I did the MT swap on my 97 Legacy today. Everything went good and it runs great. But the mileage seems to have dropped alot. On an hour drive tonight I averaged about 15mpg.

    For wiring all I've done is to splice the wires for the starter, and wire in the reverse light switch. I checked Josh's write up for Gen 1 Legs, and it says to cut pin 20 on the ECU connector. According to the FSM's for 97, pin 20 of the ECU harness goes to the TPS and the CTS, so I doubt that's the one I want to cut.

    I also now have the ABS light on. The FSM's show an input to the ABS computer from the TCU. Any idea if I need to ground this or supply a voltage?
    Dave
    [size=1][b]-86 Brat ~ Rebecca
    -97 Legacy ~ Elle
    -92 SVX LS-L ~ Princess
    [url=http://www.motorpride.com/SubieSVXRacing]-92 SVX Racer ~[/url]
    -88 XT6 ~ TBD[/b][/size]

  2. #2
    SLi Lurker AussieDan's Avatar
    Join Date
    Apr 2005
    Location
    Syracuse, NY
    Posts
    483
    Points
    9,445
    Level
    65
    Points: 9,445, Level: 65
    Level completed: 32%, Points required for next Level: 205
    Achievements:
    5000 Experience PointsO.G.
    Do you still have the TCU plugged in? From memory the auto ABS is tied in to the TCU so you'll need to keep it if you want functioning ABS.

    I do happen to have a spare manual ABS controller and actuator if you want to convert those over too.

    Which FSM are you using? The 97s are quite different from 98+ in the ABS department, let me know if you need a 97 fsm.
    2007 Audi RS4
    1997 Legacy GT - 05 WRX conversion + more | December 2008 ROTM | SOLD

  3. #3
    Needs to update their Email!
    Join Date
    Aug 2007
    Location
    Old Boston, PA
    Posts
    173
    Points
    5,901
    Level
    49
    Points: 5,901, Level: 49
    Level completed: 76%, Points required for next Level: 49
    Achievements:
    5000 Experience PointsO.G.
    I have the TCU unplugged. I can plug that back in to take care of the ABS.
    I'm more concerned with the ECU though, it seems like it's running very rich...
    Dave
    [size=1][b]-86 Brat ~ Rebecca
    -97 Legacy ~ Elle
    -92 SVX LS-L ~ Princess
    [url=http://www.motorpride.com/SubieSVXRacing]-92 SVX Racer ~[/url]
    -88 XT6 ~ TBD[/b][/size]

  4. #4
    SLi Lurker AussieDan's Avatar
    Join Date
    Apr 2005
    Location
    Syracuse, NY
    Posts
    483
    Points
    9,445
    Level
    65
    Points: 9,445, Level: 65
    Level completed: 32%, Points required for next Level: 205
    Achievements:
    5000 Experience PointsO.G.
    Not sure why it would be running so rich, possible your front O2 sensor is on the way out.

    I took a quick look at the 97 FSM and don't see any AT-only connections so I doubt that's your problem.
    2007 Audi RS4
    1997 Legacy GT - 05 WRX conversion + more | December 2008 ROTM | SOLD

  5. #5
    Needs to update their Email!
    Join Date
    Aug 2007
    Location
    Old Boston, PA
    Posts
    173
    Points
    5,901
    Level
    49
    Points: 5,901, Level: 49
    Level completed: 76%, Points required for next Level: 49
    Achievements:
    5000 Experience PointsO.G.
    Never mind, I'm an idiot...

    I took the car to AZ this morning to check the codes. One for signal from the TCU (1722), I was expecting this one. I also got a code for the MAF. As the clerk was trying to sell me a can of MAF cleaner, I had a vision in my head of the MAF wire dangling next to the valve cover.

    Went out, drove around the side of the building and popped the hood to confirm. Yep, I never plugged it in (doh). The slight stuttering and richness seems to be gone.

    I think I found the pin (#81) I need to ground to let the ECU know that I have a MT, I'll post to confirm when I try it out.
    Dave
    [size=1][b]-86 Brat ~ Rebecca
    -97 Legacy ~ Elle
    -92 SVX LS-L ~ Princess
    [url=http://www.motorpride.com/SubieSVXRacing]-92 SVX Racer ~[/url]
    -88 XT6 ~ TBD[/b][/size]

  6. #6
    Administrator Huffer's Avatar
    Join Date
    Sep 2005
    Location
    Eastlake, OH / Wellington, NZ
    Posts
    13,377
    Points
    44,297
    Level
    100
    Points: 44,297, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Achievements:
    25000 Experience PointsO.G.SocialOverdrive
    Wow, nice job on the swap... it's amazing how something as simple as an unplugged sensor slips by when you've done something as cool as a tranny swap.
    - Roger - Site Admin
    My signature is now a shout-out to the SLi veterans who keep this site flowing with good knowledge and informative opinion. You KNOW who you are, so keep it up!
    USDM 04 LL Bean H6 Wagon - TANK
    USDM 98 GT Wagon - Pandgrish - RIP; USDM 98 GT Sedan - 216k RIP; NZDM 99 GF8 - retired
    USDM 07 Honda Odyssey - Mrs Huffer;
    Live Like No One Else - Debt Free

  7. #7
    "FNG"
    Join Date
    Sep 2005
    Location
    Harwinton, CT
    Posts
    60
    Points
    7,321
    Level
    56
    Points: 7,321, Level: 56
    Level completed: 86%, Points required for next Level: 29
    Achievements:
    5000 Experience PointsO.G.
    I've been wanting to do this every since I bought my car. I had convinced myself that I would need an automatic with a child on the way. Yeah, I didn't need one that bad after all
    1998 Legacy L sedan...
    WRX bits & pieces, but factory drivetrain.

    Once upon a time I thought I needed an automatic. I now wish I could go back in time and smack the shit out of myself.

  8. #8
    Needs to update their Email!
    Join Date
    Aug 2007
    Location
    Old Boston, PA
    Posts
    173
    Points
    5,901
    Level
    49
    Points: 5,901, Level: 49
    Level completed: 76%, Points required for next Level: 49
    Achievements:
    5000 Experience PointsO.G.
    I spent some more time going through the FSM's over the weekend. I think the easy fix for the ABS is to grab a MT ABS computer.
    I grounded pin 81 of the ECU, the CEL did go out. But it's back again, I'll get the codes tomorrow to see what's going on...
    Dave
    [size=1][b]-86 Brat ~ Rebecca
    -97 Legacy ~ Elle
    -92 SVX LS-L ~ Princess
    [url=http://www.motorpride.com/SubieSVXRacing]-92 SVX Racer ~[/url]
    -88 XT6 ~ TBD[/b][/size]

  9. #9
    SLi Lurker AussieDan's Avatar
    Join Date
    Apr 2005
    Location
    Syracuse, NY
    Posts
    483
    Points
    9,445
    Level
    65
    Points: 9,445, Level: 65
    Level completed: 32%, Points required for next Level: 205
    Achievements:
    5000 Experience PointsO.G.
    Damn, guess I missed the (MT) notation on pin 81, interesting.

    Does your car have a separate ABS controller at the base of the passenger a-pillar (next to the blower motor) or the later integrated unit (with everything built into the actuator in the engine bay)?
    2007 Audi RS4
    1997 Legacy GT - 05 WRX conversion + more | December 2008 ROTM | SOLD

  10. #10
    Needs to update their Email!
    Join Date
    Aug 2007
    Location
    Old Boston, PA
    Posts
    173
    Points
    5,901
    Level
    49
    Points: 5,901, Level: 49
    Level completed: 76%, Points required for next Level: 49
    Achievements:
    5000 Experience PointsO.G.
    Quote Originally Posted by AussieDan
    Damn, guess I missed the (MT) notation on pin 81, interesting.

    Does your car have a separate ABS controller at the base of the passenger a-pillar (next to the blower motor) or the later integrated unit (with everything built into the actuator in the engine bay)?
    I didn't find pin 81 in the schematics. It wasn't until I started going through the pages of ECU diagnostics that I found it.

    For the ABS?? I don't know, I'll have to take a look.
    Dave
    [size=1][b]-86 Brat ~ Rebecca
    -97 Legacy ~ Elle
    -92 SVX LS-L ~ Princess
    [url=http://www.motorpride.com/SubieSVXRacing]-92 SVX Racer ~[/url]
    -88 XT6 ~ TBD[/b][/size]

  11. #11
    SLi Supporter
    Join Date
    Nov 2006
    Location
    Cayman Islands
    Posts
    1,057
    Points
    9,955
    Level
    66
    Points: 9,955, Level: 66
    Level completed: 77%, Points required for next Level: 95
    Achievements:
    5000 Experience PointsO.G.
    did you reset the ECU?
    [url]http://www.CSN.Ky[/url] - Cayman Islands Sport Car Community
    October 2007 ROTM Winner

    PSN Username - Boxertech
    Regular COD4 and Fifa09 Players

  12. #12
    Needs to update their Email!
    Join Date
    Aug 2007
    Location
    Old Boston, PA
    Posts
    173
    Points
    5,901
    Level
    49
    Points: 5,901, Level: 49
    Level completed: 76%, Points required for next Level: 49
    Achievements:
    5000 Experience PointsO.G.
    I reset the ECU this morning, and after driving around for a bit to run some errands, it hasn't returned yet.

    I got a PM asking about the ECU wire I grounded. It was pin 81. There was no wire in that spot, so I had to improvise. To help ID the correct space 79-L, and 82-LR.

    I also got the cruise control working again today, It was easier than I thought. On the plug on the CC unit I removed the pins 3-GY and 4-LR (LgB in Canada). That is all you need to do to get the cruise working. But, unless you wire in the front/blue switch on the clutch pedal, the engine will rev high if you have the cruise set and go on the clutch. To take care of that, splice the clutch switch into series with the 1-YW wire on the brake switch.

    I was going to wire in the back clutch switch, so that the clutch has to be engaged to start the car, but I decided to leave it as is.

    As long as the CEL stays out, I'm pretty much done with the swap. Like I mentioned, I'll grab a MT ABS unit, next time I'm at the yard.
    Dave
    [size=1][b]-86 Brat ~ Rebecca
    -97 Legacy ~ Elle
    -92 SVX LS-L ~ Princess
    [url=http://www.motorpride.com/SubieSVXRacing]-92 SVX Racer ~[/url]
    -88 XT6 ~ TBD[/b][/size]

  13. #13
    Needs to update their Email!
    Join Date
    Aug 2007
    Location
    Old Boston, PA
    Posts
    173
    Points
    5,901
    Level
    49
    Points: 5,901, Level: 49
    Level completed: 76%, Points required for next Level: 49
    Achievements:
    5000 Experience PointsO.G.

    Re: 97 AT->MT swap, ECU question

    Just thought I'd update this thread. I continued to have an issue with the CEL returning after about 90 minutes of driving.

    I finally got an ECU out of a 97 MT, swapped that in and no no more CEL. So if anyone else is going to do this swap and wants to avoid the CEL, get the ECU as well.
    Dave
    [size=1][b]-86 Brat ~ Rebecca
    -97 Legacy ~ Elle
    -92 SVX LS-L ~ Princess
    [url=http://www.motorpride.com/SubieSVXRacing]-92 SVX Racer ~[/url]
    -88 XT6 ~ TBD[/b][/size]

  14. #14
    SLi Lurker T_F_E's Avatar
    Join Date
    Dec 2008
    Location
    Metaline Falls, Washington
    Posts
    426
    Points
    5,665
    Level
    48
    Points: 5,665, Level: 48
    Level completed: 58%, Points required for next Level: 85
    Achievements:
    5000 Experience PointsO.G.

    Re: 97 AT->MT swap, ECU question

    So how much in total did this swap cost? I really really want to do this
    Tell me how I'm doing on my 1997 Outback Legacy Limited

    My trucks lugnuts take more torque than my subaru produces.

  15. #15
    Needs to update their Email!
    Join Date
    Aug 2007
    Location
    Old Boston, PA
    Posts
    173
    Points
    5,901
    Level
    49
    Points: 5,901, Level: 49
    Level completed: 76%, Points required for next Level: 49
    Achievements:
    5000 Experience PointsO.G.

    Re: 97 AT->MT swap, ECU question

    Quote Originally Posted by T_F_E
    So how much in total did this swap cost? I really really want to do this
    That's gonna depend on where you get your donor trans. All together I'm under $300.

    $100 --Trans, Starter, Linkage, pedal box, flywheel (From a U-Pull yard)
    $40 --Flywheel cutting
    $120 --Ebay clutch
    $20 --Gear Oil
    Dave
    [size=1][b]-86 Brat ~ Rebecca
    -97 Legacy ~ Elle
    -92 SVX LS-L ~ Princess
    [url=http://www.motorpride.com/SubieSVXRacing]-92 SVX Racer ~[/url]
    -88 XT6 ~ TBD[/b][/size]

  16. #16
    SLi Lurker T_F_E's Avatar
    Join Date
    Dec 2008
    Location
    Metaline Falls, Washington
    Posts
    426
    Points
    5,665
    Level
    48
    Points: 5,665, Level: 48
    Level completed: 58%, Points required for next Level: 85
    Achievements:
    5000 Experience PointsO.G.

    Re: 97 AT->MT swap, ECU question

    wow... how long did it take you?
    Tell me how I'm doing on my 1997 Outback Legacy Limited

    My trucks lugnuts take more torque than my subaru produces.

  17. #17
    Needs to update their Email!
    Join Date
    Aug 2007
    Location
    Old Boston, PA
    Posts
    173
    Points
    5,901
    Level
    49
    Points: 5,901, Level: 49
    Level completed: 76%, Points required for next Level: 49
    Achievements:
    5000 Experience PointsO.G.

    Re: 97 AT->MT swap, ECU question

    Quote Originally Posted by T_F_E
    wow... how long did it take you?
    I did the swap itself in a day. But I've done my share of swap's with other Subaru tranny's. And then a few hours on a few other days to sort out the little wiring differences.

    If you know what your doing, this could easily be done in a weekend.
    Dave
    [size=1][b]-86 Brat ~ Rebecca
    -97 Legacy ~ Elle
    -92 SVX LS-L ~ Princess
    [url=http://www.motorpride.com/SubieSVXRacing]-92 SVX Racer ~[/url]
    -88 XT6 ~ TBD[/b][/size]

  18. #18
    SLi Supporter
    Join Date
    Nov 2006
    Location
    Cayman Islands
    Posts
    1,057
    Points
    9,955
    Level
    66
    Points: 9,955, Level: 66
    Level completed: 77%, Points required for next Level: 95
    Achievements:
    5000 Experience PointsO.G.

    Re: 97 AT->MT swap, ECU question

    dont forget the M/T driveshaft.

    Thanks for giving us a update BTW, i like when members not leave us hanging lol
    [url]http://www.CSN.Ky[/url] - Cayman Islands Sport Car Community
    October 2007 ROTM Winner

    PSN Username - Boxertech
    Regular COD4 and Fifa09 Players

  19. #19
    Needs to update their Email!
    Join Date
    Aug 2007
    Location
    Old Boston, PA
    Posts
    173
    Points
    5,901
    Level
    49
    Points: 5,901, Level: 49
    Level completed: 76%, Points required for next Level: 49
    Achievements:
    5000 Experience PointsO.G.

    Re: 97 AT->MT swap, ECU question

    Quote Originally Posted by subba
    dont forget the M/T driveshaft.
    Yeah, forgot to list that...

    You can get just the front half of the driveshaft though. Which is helpful since Harry's started charging for two driveshafts when you get a Soob driveshaft :smt012
    Dave
    [size=1][b]-86 Brat ~ Rebecca
    -97 Legacy ~ Elle
    -92 SVX LS-L ~ Princess
    [url=http://www.motorpride.com/SubieSVXRacing]-92 SVX Racer ~[/url]
    -88 XT6 ~ TBD[/b][/size]

  20. #20
    New User
    Join Date
    Jun 2009
    Posts
    1
    Points
    4,146
    Level
    40
    Points: 4,146, Level: 40
    Level completed: 98%, Points required for next Level: 4
    Achievements:
    1000 Experience PointsO.G.

    Re: 97 AT->MT swap, ECU question

    what kind of "little wiring differences" did you face?


    how hard were they to overcome?

  21. #21
    SLi Resident Benfolio's Avatar
    Join Date
    Mar 2008
    Location
    Cedarburg, Wi
    Posts
    550
    Points
    7,328
    Level
    56
    Points: 7,328, Level: 56
    Level completed: 89%, Points required for next Level: 22
    Achievements:
    5000 Experience PointsO.G.

    Re: 97 AT->MT swap, ECU question

    Huh. Never saw this thread before. Good to know about the cruise fix. I can deal with no ABS, but cruise? Nah.

    i STILL haven't wired mine correctly. I have all the harnesses and modules out of the '97, but have been too lazy to splice, or swap, them into the '98 to take care of the NSS, the CEL (due to the NSS being in neutal all the time), the ABS, and the cruise.
    1997 2.5GT MT Sedan - Part out! - CLICK HERE FOR THE LIST/PICS
    1998 Legacy L Wagon - 204k and SOLD 6/10/12
    1997 C1500 Silverado Extended Cab
    2004 Quest 3.5SE Space Shuttle

  22. #22
    Needs to update their Email!
    Join Date
    Aug 2007
    Location
    Old Boston, PA
    Posts
    173
    Points
    5,901
    Level
    49
    Points: 5,901, Level: 49
    Level completed: 76%, Points required for next Level: 49
    Achievements:
    5000 Experience PointsO.G.

    Re: 97 AT->MT swap, ECU question

    Quote Originally Posted by Blackheat68
    what kind of "little wiring differences" did you face?


    how hard were they to overcome?
    Sorry, just saw this post...

    Other than the ones mentioned earlier in this post, the only one I can think of is wiring the reverse switch into the harness that went to the indicator on the AT.

    -There are two switches on the MT trans, use a meter to check for continuity. One will be closed when in "R", the other will be closed anytime you're in a gear. Use the one that's closed when you're in "R"

    -From the AT to the chassis there are 2 large connectors, the smaller of the 2 went to the indicator on the side of the trans. Determine which connectors sense "R" and wire the 2 wires from the "R" switch on the MT into those. It's continuity so polarity doesn't matter.
    Dave
    [size=1][b]-86 Brat ~ Rebecca
    -97 Legacy ~ Elle
    -92 SVX LS-L ~ Princess
    [url=http://www.motorpride.com/SubieSVXRacing]-92 SVX Racer ~[/url]
    -88 XT6 ~ TBD[/b][/size]

  23. #23
    "FNG" daleyswanson's Avatar
    Join Date
    Dec 2009
    Location
    Pacific Northwest
    Posts
    82
    Points
    3,949
    Level
    39
    Points: 3,949, Level: 39
    Level completed: 99%, Points required for next Level: 1
    Achievements:
    1000 Experience PointsO.G.

    Re: 97 AT->MT swap, ECU question

    i wanted to do this but i figure i will do it when i swap in another engine, and just do engine, tranny and ECU to match it all. thats awesome you did it for 300 though. that part caught me off guard

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •