[Sea-J]

Is there a way to do a complete reset of the ECU? I see on several sites that you can paperclip some pins on newer models but there is no information or vids on the older 1991 GT 5s-fe. Pulling the neg batt terminal doesn't seem to do the trick. Must be a hack somewhere on the under hood driver side port.
Other option is to pick up a donner from a bone yard or eBay.
Also the ecu is hidden under the center console. Is there an easier way to get it out other than pulling the dash out?

 

[sefiro]

Ecu reset , pull both neg and pos battery cables. Hold them together for 10 seconds. That will drain down the capacitors that hold history and settings.

The ECU is mounted with 3 breakers and bolts. You'll need to pull the carpet back on both sides to access. Unplug wire harness (passenger side). Remove 3 bolts (2 driver side, 1 passenger). The ECU should be loose and street to slide out passenger side. There is an relay attached to the shift side of the ecu that should be unplugged. You might have to remove a bracket from the driver side of the ecu to get it out.

(BTW, on a separate post, you had pulled the radio and asked about extra plugs. Those plugs are not ecu plugs)

 

[Sea-J]

Thank you again. I'm still in the process of buttoning up from the last timing check/adjustment, still have to put the alt and ps back together.
After everything I've done with this baby it should last another 30 years if it runs. Replaced, repaired, tested, fixed, just about every part that would make the motor run. Don't let anyone fool you by saying "it ran when it was stored....5 years ago. Forget the mice, chipmunks, squirrels, bugs, dry hoses, broken fittings, cracked belts and on and on.
My history with cars go back to an old '37 Nash Lafayette. Last uncomputerized car I had was a new '72 country squire wood grain and all with a Windsor 400 and a C6. When computers started showing up I got lost. Had a hobby of classic wood and boat restoration, could pull an outboard apart in my sleep, rebuilt an AMC 327 from the bottom up. . Appreciate the assistance. How do you know so much about these things? Just curious.

 

[sefiro]

Started with my first car , 74 Celica. Drove it like crazy and blew the hg. On advice of hs friends, they convinced me that a hg replacement is easy, and a rebuild was a little more. 6 weeks later, and a few left over bolts, car was running again.

Consulting career sidetracked me for 2 decades. 4 hours later, and a lot of cars in the driveway, got back to the hobby of putting their cars back together (lots of Cadillac hand downs from their grandfather). During that time, bought a used 3rd gen and eventually a new 5th gen.

I've rebuilt the 5th gen twice, on the 3rd tranny, front end totaled twice (people hitting me), on a salvage tile, driven coast to coast, skiing in Vermont, and in Colorado,. . . Got my money's worth.

 

[Sea-J]

You're qualified. Doing the reset thing now but don't have much faith on a fix. I'm afraid I'll be naming it the Straw Man and send it to the wizard in the land of OZ. Nothing left. Repaired, replaced, cleaned. all parts and connections and connectors and the way it failed last fall internet searches point to the old brain. No regrets on replacing old parts though. Money well spent to have a reliable driver to take to summer shows. I'll put the right front tire back on and off the stand she'll come.
Next removing the seats, console and carpet to get to the well hidden box. Just want to get it out and match numbers before ordering a new one. I think there's a difference with or without turbo.
Who knows, maybe a new ECU would fix the shifting problem. TBD.

 

[sefiro]

The 5th gen ecu's have capacitors that are failing now a days. Plenty of posts on which one to get. If you get it out, open it up and had a look.

 

[Sea-J]

I'll start a new thread for the removal. Be putting in new carpet anyway.
I'll also try to post more pics for anyone.