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  1. #1

    Default '84 SVO raising idle by itself

    Hey all,

    I just picked up an 84 SVO which seems to have the mods to turn it into an 86 power-wise. It also has an adjustable frp and boost controller. I'm having one annoying issue with the car. When driving, it will slowly raise the idle every time I come to a stop. Say I set it to 1000 with the screw, if I drive down the road and stop at a light, it will be at 1100. Drive a little more and stop again and it's at 1400, it just does this until I lower the idle screw at which point the cycle will repeat. I have reset the base idle, cleaned the IAC with carb cleaner and checked the TPS voltage as well as set it properly and it still does this. Any thoughts on what to do next?

    Thanks!
    Last edited by Beyondthesea; 05-04-2017 at 02:15 PM.

  2. #2

    Default

    Might be sucking air somewhere. Spray carb cleaner around the intake while running........see if idle rises. Mine does it when its cold then its fine when it warms up.

  3. #3

    Default

    Quote Originally Posted by chads84svo View Post
    Might be sucking air somewhere. Spray carb cleaner around the intake while running........see if idle rises. Mine does it when its cold then its fine when it warms up.
    Thanks, I actually did the carb cleaner test and the idle didn't change at all so it all seems fine on that front. I actually unplugged the IAC and drove it around for a while and the idle didn't rise at all. I'm going to try to bathe it in carb cleaner for a while and see if that helps. If not I may just replace it.

  4. #4
    FEP Power Member
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    It is the throttle position sensor. They are known for doing that.
    Kendal

  5. #5
    FEP Power Member SchoolBoy's Avatar
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    What voltage did you get on the tps? Some people have had luck setting them as low as .88 to make this issue go away. Also check all your gounds including the one by the eec.
    If you blink at the end of the straight away you'll miss the twisties and what fun would that be!
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  6. #6

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    On my car, the air bypass valve will stick and cause a high idle, if I shut it off and restart it, it usually resets or "unsticks" and idles back down. I've actually had to change it a couple of times in the last 34 years. No big deal.
    JK
    1983 Capri RS Turbo (since new)
    1970 Boss 302 (since 1980)
    1965 Mustang Coupe (since 1976)

  7. #7
    FEP Super Member erratic50's Avatar
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    I forget as it's been a long time since I've gotten the privilege of messing with one ..... Is the IAC on the SVOs similar or the same as other Ford cars? If so, there may be an adjustable IAC available. That along with dropping voltage at the TPS may help if its throttle related.

    Now for more general thoughts.

    Is the car showing any codes?

    You mentioned boost controller mods. Are the boost controls working properly or are you seeing stupid stuff like boost building and ultimately showing boost present at idle when these situations are happening?

    Check your brake booster and other vacuum lines for leaks also.

  8. #8
    FEP Power Member dagenham's Avatar
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    As stated above. Replace the tps.

  9. #9
    FEP Super Member erratic50's Avatar
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    +1 on TPS. It's a good place to start.

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