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Thread: Turbo II Curiosity Question

  1. #1
    Garrett booster
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    Turbo II Curiosity Question

    I have now had my '89 GTC Turbo II convertible for more than a year. Seems to run well, but something I have come to realize is that it does not seem to be able to get to the maximum boost of 12 PSI. It's possible my boost gauge is wrong, but I believe the boost kicks out sooner than it should. According to the gauge, I don't believe it has ever made 10 PSI. I'd be surprised if it has ever gone above 7-8 PSI. I assume this is not normal. Does anyone have any thoughts as to why my Turbo II seems to be behaving more like a Turbo I (computer, vacuum problem, etc.)? What can I do to allow the boost to keep going up before the wastegate is engaged? I assume that's what's happening. Thanks!


  2. #2
    Supporting Member Turbo Mopar Contributor
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    Re: Turbo II Curiosity Question

    The factory boost gauges are known to be inaccurate. I would suggest backprobing the MAP with a DVM to determine what is really going on.
    Is the wastegate plumbed up as per the vacuum diagram on inside of the hood?
    Regards,
    Miles

    DD '87 Sundance T1, SLH with rear disks
    '87 CSX #432 2.5 CB TII, SLH

  3. #3
    Rhymes with tortoise. Turbo Mopar Staff cordes's Avatar
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    Re: Turbo II Curiosity Question

    I too would check the vac line routing. Was the 89 TII still different than the 89 TI routing? I believe the 89 TI routing would fail to minimum boost pressure if the solenoid went bad.

  4. #4
    Garrett booster
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    Re: Turbo II Curiosity Question

    Quote Originally Posted by cordes View Post
    I too would check the vac line routing. Was the 89 TII still different than the 89 TI routing? I believe the 89 TI routing would fail to minimum boost pressure if the solenoid went bad.
    I'll need to check the routing, as suggested. I assume you are talking about the wastegate solenoid? Would "minimum boost pressure" be 7 PSI?

  5. #5
    Rhymes with tortoise. Turbo Mopar Staff cordes's Avatar
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    Re: Turbo II Curiosity Question

    Yes. The boost control solenoid is the one you want to look at. Minimum boost is right around 7PSI for our WG cans.

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