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Thread: Balancing TBIs

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    Default Balancing TBIs

    I have been having a issue with hesitation when accelerating. I have had both TBIs rebuilt by DCS. I have replaced the stock fuel pump with an 85. I replaced the fuel filter today and set the timing and when I went to balance the TBIs I had no vacuum on the Manometer. I am assuming I have a vacuum leak somewhere but I am looking for advice as to where to start looking.

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    Moderator KANE's Avatar
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    Quote Originally Posted by ed82 View Post
    I have been having a issue with hesitation when accelerating. I have had both TBIs rebuilt by DCS. I have replaced the stock fuel pump with an 85. I replaced the fuel filter today and set the timing and when I went to balance the TBIs I had no vacuum on the Manometer. I am assuming I have a vacuum leak somewhere but I am looking for advice as to where to start looking.
    Hi!

    Just seeing this now- sorry for the delay.

    Sounds like you may have dirty balance ports... or are using the wrong vacuum port(s). I'm not sure I've ever heard of both ports being blocked unless you had the TBs bored larger.

    _________________________________________

    HOW TO BALANCE:

    If the anti tamper wild and plug have been removed... setting the balance is simple.


    You'll need to build a water manometer and attach each side to a balance port.

    Lots of threads around that talk to it, basically you'll need about five feet of 1/4 clear vinyl hose, a thin piece of wood or cardboard, clear packaging tape, a ruler, and then some water with blue food coloring.

    Here's the short story on how to build a water manometer and to set the idle...

    • Tape the ruler to the piece of wood.
    • Find the middle of the tubing, and set that below the ruler.
    • Tape the tubing in such a way that it runs along the side of the ruler.
    • Fill the tube with about 5mil of the colored water. I use blue because it is easy to see. I also use an oral syringe to measure out and fill the tubing.
    • Disconnect the IACs.
    • Connect the tubes to the balance ports on each TB.
    • Use a sheet of paper to gauge the opening of each throttle blade and then adjust until they are visually equal.
    • Start the car.
    • Adjust either the balance screw on the front TB and/or the rear idle speed screw on the rear TB until they are equal. If you suck in some water on one side- shut the car off adjust either screw as needed. Just remember- the driver's side idle screw adjusts the idle speed while the screw on the passenger TB adjust the opening & balance. Keep doing this until both sides pull evenly against each other and you have the minimum idle you are looking for. Don't worry- sucking in 5mils of water won't hurt it.


    Hope that helps!!!

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    Member djsroknrol's Avatar
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    Default

    Quote Originally Posted by KANE View Post
    Hi!

    Just seeing this now- sorry for the delay.

    Sounds like you may have dirty balance ports... or are using the wrong vacuum port(s). I'm not sure I've ever heard of both ports being blocked unless you had the TBs bored larger.

    _________________________________________

    HOW TO BALANCE:

    If the anti tamper wild and plug have been removed... setting the balance is simple.


    You'll need to build a water manometer and attach each side to a balance port.

    Lots of threads around that talk to it, basically you'll need about five feet of 1/4 clear vinyl hose, a thin piece of wood or cardboard, clear packaging tape, a ruler, and then some water with blue food coloring.

    Here's the short story on how to build a water manometer and to set the idle...

    • Tape the ruler to the piece of wood.
    • Find the middle of the tubing, and set that below the ruler.
    • Tape the tubing in such a way that it runs along the side of the ruler.
    • Fill the tube with about 5mil of the colored water. I use blue because it is easy to see. I also use an oral syringe to measure out and fill the tubing.
    • Disconnect the IACs.
    • Connect the tubes to the balance ports on each TB.
    • Use a sheet of paper to gauge the opening of each throttle blade and then adjust until they are visually equal.
    • Start the car.
    • Adjust either the balance screw on the front TB and/or the rear idle speed screw on the rear TB until they are equal. If you suck in some water on one side- shut the car off adjust either screw as needed. Just remember- the driver's side idle screw adjusts the idle speed while the screw on the passenger TB adjust the opening & balance. Keep doing this until both sides pull evenly against each other and you have the minimum idle you are looking for. Don't worry- sucking in 5mils of water won't hurt it.


    Hope that helps!!!

    Don't forget to block the IAC ports with something....I use a cut up knee pad carved to fit the kidney shaped holes
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