Trying to figure out this car and idle issue.

Discussion in '96-04 - 4V Specific' started by Ythrashin, Apr 5, 2017.

  1. Ythrashin

    Ythrashin New Member

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    Just bought this 97 GT with 98 cobra engine in it. Having some idle issues. Also few other questions.

    Was hoping you could help me.

    What is this vacuum for?

    [​IMG]
     
  2. Ythrashin

    Ythrashin New Member

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    Also this is unplugged. What is it for?

    [​IMG]
     
  3. Ythrashin

    Ythrashin New Member

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    This is what I started with.

    [​IMG]

    It has the GT hood on it and was hitting the plenum. The IAC was cracked. Bolt was broke off in plenum where they tried to remove the IAC. The plenum also had a crack in it that he said he jb welded.

    I replaced the plenum with one i found at a salvage yard, which had another IAC on it.

    [​IMG]

    Had to grind and cut a chunk out of the underside of the hood to clear the plenum.
     
  4. Ythrashin

    Ythrashin New Member

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    Im learning as I go. I need to figure out what kind of transmission is in the car also. Previous owner said it has an 04 GT tranny in it.

    I also have been wondering if they used the gt computer or cobra in the swap. Read somewhere that if they used the cobra they wouldve had to of swapped out the fuel pump also. If they used the gt computer it wouldve needed a tune...

    Ive asked the PO, but he says he cant remember. Lol
     
  5. Ythrashin

    Ythrashin New Member

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    Im planning on just tearing into it and trying to figure this crap out myself


    Any tips would be appreciated..?
     
  6. Ythrashin

    Ythrashin New Member

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    Was thinking about capping off that vacuum line in my first post for now. That line as it goes further down looks corroded all to hell....
     
  7. 98snakehorse

    98snakehorse Well-Known Member

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    Which vacuum line are you talking about? In the first photo, there were a few. One goes to your FPR and the other I think goes to your charcoal canister and one goes to your vac line to run your air vents..
     
  8. Ythrashin

    Ythrashin New Member

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    The one with the red stripe on it.
     
  9. 98snakehorse

    98snakehorse Well-Known Member

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    That one is heading to your inner passenger fender to the charcoal canister. It cycles out fuel vapors from the gas tank its another part of the cars emissions.
     
  10. 07GtS197

    07GtS197 Well-Known Member

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    Is your car stick or auto? What rear gears do you have? You actually dont need a tune for a 4v swap but it will net you more power. You can pull off the passenger kick panel and get the computer code for us.
     
  11. Ythrashin

    Ythrashin New Member

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    I dont think the high/fluctuating idle is from that line. I popped it off and plugged it and the idle didnt improve. Any other ideas?

    Perhaps my IAC is bad or MAF?

    There is some damage to the inside of the air inake tube but didnt look like any air is getting through. The throttle body was caked with carbon deposits. Cleaned it off really good when i had everything apart. Maybe something wrong with it...

    Any idea what that plug goes to in my second pic?
     
  12. Ythrashin

    Ythrashin New Member

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    It's a stick/5 speed.

    Ok, ill go get that code

    Not sure about the rear gears...
     
  13. Ythrashin

    Ythrashin New Member

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    [​IMG]

    No number on the damn computer...
     
  14. 07GtS197

    07GtS197 Well-Known Member

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    Maybe that vac line in the second pic if for the ac blend door. Most likely the trans is not from an 04 because they used a tr3650 which uses a different trans mount and if Im not mistaken uses a different signal for the speedo making the swap difficult. It can be done but I doubt it was done. Maybe theres a tag on it to verify what trans it is.

    I wouldnt worry about the computer then. Do you have the stock imrc's? If it doesnt and isnt throwing a cel then you have a gt ecu. If it has the imrc's deleted and there is a cel then you have a cobra ecu.
     
  15. Ythrashin

    Ythrashin New Member

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    Yeah, that's why he said the speedometer doesnt work. How can I tell if the IMRCs are deleted?

    I have only one cel snd thats the speed sensor...
     
  16. 07GtS197

    07GtS197 Well-Known Member

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    Hmm then it could be swapped who knows. If you can see around the back of the intake next to the firewall you should be able to see a small black plastic control box and a linkage between both banks of intake runners. I know thats not really a good explanation lol but I dont know how else to describe it. You could always take the intake manifold off to be 100% sure.

    To make this more convaluted lol I just thought of something. If he swapped computers and didnt swap engine wiring harnesses then it wouldnt have the connector for the imrc's and if there isnt a tune it would throw a code for them.

    OP here is a thread I found about some info regarding a tr3650 swap and how to make the speedo work.

    http://www.allfordmustangs.com/foru...wapping-t45-tr3650.html#/topics/270828?page=1
     
  17. Ythrashin

    Ythrashin New Member

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    So I figured out im running with the gt computer. Dont think it has a tune. Whats the best way(lowest cost) to correct this?switch out the computer with a cobra one or do i have to get a custom tune?
     
  18. Ythrashin

    Ythrashin New Member

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    If the imrcs arent deleted? Seems to run pretty damn good now. Wish i had something to comare it to...a stock cobra..
     
  19. Ythrashin

    Ythrashin New Member

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    Did some reading. Read if the imrcs are still yhere then im only running on 2Vs. Im thinking my best course of action is to deyerimine if the imcs are deleted, if not delete them. Also, get a cobra ecu and swap it with the gt ecu...
     
  20. SnakeBit!

    SnakeBit! Active Member

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    to save money, you can wire the IRMC's open and you will still need a tune.