Hey guys! Transmission and engine modifications - 97 STS
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  • 1 Post By Aztec ETC ECS
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Cadillac Seville / Cadillac Eldorado Forum Discussion, Hey guys! Transmission and engine modifications - 97 STS in Past Cadillac Vehicle Discussion; I've learned quite a bit from this forum so far while lurking so figured I would just drop in and ...
  1. #1
    ScientificRacing's Avatar
    ScientificRacing is offline Cadillac Owners Member
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    Hey guys! Transmission and engine modifications - 97 STS

    I've learned quite a bit from this forum so far while lurking so figured I would just drop in and say hello. I've got a '97 STS black on black and I love this car. I bought the car to actually race with. I'm a huge fan of the quad cam 4.6 N*. I've already done a little work to the car, intake, working on the exhaust, and some weight reduction. As soon as I get the transmission working the way I want it (I actually need you guys' help with that) its going on a 75+shot of the giggle gas.

    Anyway, I need some help finding the transmission pressure control solenoid power wire.


    I see the solenoid here but can't find it in the engine bay, much less the harness with the power wire. I hope this picture is for the 4T80e not the 4T80, as there are some significant difference between them iirc.

    Is it even possible to get to the wire without dropping the cradle? Any input is greatly appreciated!

    Thanks guys! Again it feels good to be on a new forum.

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    Submariner409's Avatar
    Submariner409 is offline If it won't run, stick on fender vents
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    Re: Hey guys!

    Intake and exhaust "work" - 1997 - you'll need a good PCM guru to do some tuning to realize even .0004 hp out of whatever you did. Talk to Lyndon Wester at Wester's Garage, Canada or look up an old CF member, AJxtcman.

    Nitrous - may I suggest that you remove the 1997 engine, do a top overhaul with studs so you don't sent both heads into orbit ? By now your cams and cam followers are wearing thin ..............

    You'll need a GM wiring diagram, and the wiring harness loops around and down on the radiator side of the "bell housing".

    www.alldatadiy.com

  4. #3
    ScientificRacing's Avatar
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    Re: Hey guys!

    Hmmm ok. Are you talking about the full 20 pin harness or just the harness for the pressure solenoid? Apparently, the power/ground wire is labeled "E".

  5. #4
    ScientificRacing's Avatar
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    Re: Hey guys!

    So I found the pages I need from the manual


    And...

    http://www.fiero.nl/forum/Archives/A...-2-048609.html

    From my understanding the wire runs from the pcm to the trans then back to the pcm. However, there's more than one harness and the wires are DIFFERENT colors in different harnesses. I have no idea which harness is which so I cant locate the correct wire because they're are not consistent in their colors.

    Does anyone have pictures of the harnesses labeled?

    Also, I'm not too keen on electrical service but would cutting the wire "before" or "after" the trans make a different or would it yield the same results? I'm assuming no difference since its breaking the circuit either way.

    Thanks guys!

  6. #5
    basscatt's Avatar
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    Re: Hey guys!

    NITROUS - in a 97 Northstar - without studs -

    ---- --- BOOM -

  7. #6
    MoistCabbage's Avatar
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    Isn't there someone here with an Eldo on Nitrous?

  8. #7
    ScientificRacing's Avatar
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    Re: Hey guys!

    Quote Originally Posted by basscatt View Post
    NITROUS - in a 97 Northstar - without studs -

    ---- --- BOOM -
    Hahaha as ridiculous as it sounds, yes. I've actually seen quite a few accounts of nitrous on these engines. There were some on the other caddy forum (I forgot which one it was) and a few Pontiac ones as well. These engines are VERY stout. The limiting factor at this point is the tranny (axles) and fuel system.

    Bump!
    Still need help trying to identify that wire. In the mean time, I'm replacing the front motor mount (Its disintegrated )

  9. #8
    ScientificRacing's Avatar
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    Re: Hey guys!

    Quote Originally Posted by Submariner409 View Post
    Intake and exhaust "work" - 1997 - you'll need a good PCM guru to do some tuning to realize even .0004 hp out of whatever you did. Talk to Lyndon Wester at Wester's Garage, Canada or look up an old CF member, AJxtcman.

    Nitrous - may I suggest that you remove the 1997 engine, do a top overhaul with studs so you don't sent both heads into orbit ? By now your cams and cam followers are wearing thin ..............

    You'll need a GM wiring diagram, and the wiring harness loops around and down on the radiator side of the "bell housing".

    www.alldatadiy.com
    Not sure why I didnt see the first part of your post until now :/ Anyway, I know the HG/thread/bolt is a serious weak point on these engines but I'm just trying to have a little fun with it before I tear it down and build it. Also, I thought these were adaptive PCM's that adjust to changes (within its limitations, of course)?

    Anyway, no help on the wire so I guess I'm taking it to the stealership to locate and identify the wire.

  10. #9
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    Re: Hey guys!

    Due to EPA limitations our ECM/PCM's are so "tight" that it isn't funny. Literally no adaptive capability for air/fuel ratio changes outside the set maps.

    "Tear it down and build it" means returning it to stock condition.

    BTW - You need to do some GM service manual study on the 4T80E transmission "adaptive" shift and line pressure control features that override other outside "interference".

    Maybe - just maybe - Wester's Garage in Canada does some pre-1998 PCM/ECM work. Google them.

  11. #10
    Aztec ETC ECS's Avatar
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    Re: Hey guys!

    Nitrous in a Northstar? The only time I had nitrous in my Cadi is when I took a bottle to get refilled.

    This reminds me of an old cartoon:


    I can only do it once!

    But seriously,
    Quote Originally Posted by ScientificRacing View Post
    Anyway, no help on the wire so I guess I'm taking it to the stealership to locate and identify the wire.
    Sub told you where the harness is- "the wiring harness loops around and down on the radiator side of the "bell housing" and goes into the case. And you supplied the colors yourself- Lt Blu/Wht & Red/Blk

    What exactly do you plan on doing when you find these wires?

    ----------

    You may also want to run a 50/50 mix of sealer/water!
    (Just kidding, don't do that. Although.... no, don't do it)
    basscatt likes this.

  12. #11
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    Re: Hey guys!

    Quote Originally Posted by Aztec ETC ECS View Post
    Nitrous in a Northstar? The only time I had nitrous in my Cadi is when I took a bottle to get refilled.

    This reminds me of an old cartoon:


    I can only do it once!

    But seriously,

    Sub told you where the harness is- "the wiring harness loops around and down on the radiator side of the "bell housing" and goes into the case. And you supplied the colors yourself- Lt Blu/Wht & Red/Blk

    What exactly do you plan on doing when you find these wires?

    ----------

    You may also want to run a 50/50 mix of sealer/water!
    (Just kidding, don't do that. Although.... no, don't do it)
    -------------------
    What exactly do you plan on doing when you find these wires?


    I think he is going to rewire the steering wheel switches to make it "paddle-shift" -
    that will go nicely with the nitrous -

    Aztec ETC ECS likes this.

  13. #12
    MoistCabbage's Avatar
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    Quote Originally Posted by basscatt
    -------------------
    What exactly do you plan on doing when you find these wires?

    I think he is going to rewire the steering wheel switches to make it "paddle-shift" -
    that will go nicely with the nitrous -
    Marks turbo'd '99 is set up that way.

  14. #13
    Aztec ETC ECS's Avatar
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    Re: Hey guys! Transmission and engine modifications - 97 STS

    I guess you could put a toggle switch on one of the wires to get full line pressure while spraying.
    Clear codes when finished if motor is still living.

    I hooked the spray up to the cruise button in my Olds. (just sayin')

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