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High Idle after APS and 317 heads install

This is a discussion on High Idle after APS and 317 heads install within the Computer & Tuning forums, part of the LSx Technical Help Section category; After installing APS Twin turbo system and 317 heads I started the car up and it idles fine for a ...

  1. #1
    Member fil131's Avatar
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    High Idle after APS and 317 heads install

    After installing APS Twin turbo system and 317 heads I started the car up and it idles fine for a while.

    When it idles for a while it starts climbing and sits around 2200 to 2400 RPM, if I shut it down and start it back up same thing.

    Once it reaches operating temp, it will go to 2200 or 2400 RPM and sit there right away.

    Do you think I forgot something or I need to tune for something?

    I wanna drive the car to the tuneshop 19 miles away, but if I can't get it to idle normal then I'll just trailor it there.

    Any Ideas guys?
    02 NBM WS6
    APS TT LG Upgraded Snails
    317's
    60# Mototrons
    Tuned by Sean@Solid-Technology
    610RWHP

    Nitrous is no more than a turbo or a supercharger wrapped up in a bottle

  2. #2
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    well you probably need a tune because the forced air is probably opening the throtle, but it sounds like vaccum leak who did the engine work for you?,

    if you rather be safe then rent a tow jack and tow it, but if your car is not over heating or doing something erratic (besides the idling) then drive it make shure you dont revv it too much keep it under 3K to be safe.

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    Member fil131's Avatar
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    Quote Originally Posted by hurraquio View Post
    well you probably need a tune because the forced air is probably opening the throtle, but it sounds like vaccum leak who did the engine work for you?,

    if you rather be safe then rent a tow jack and tow it, but if your car is not over heating or doing something erratic (besides the idling) then drive it make shure you dont revv it too much keep it under 3K to be safe.
    I did all the work myself, I wouldnt think the forced air is pushing the throttle open because under 3200 I should not be hitting boost, I would think if it was a vacuum leak kit would happen from the beginning, not after ideling for a while or at warm up, but your guess is as good as mine(probably better)

    Anyone else have a take on this.

    I am taking the car to the tuner tomorrow, but want to get this idle issue taken care of before I drive it there.

  4. #4
    The Bandit Wesman's Avatar
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    Quote Originally Posted by fil131 View Post
    I did all the work myself, I wouldnt think the forced air is pushing the throttle open because under 3200 I should not be hitting boost, I would think if it was a vacuum leak kit would happen from the beginning, not after ideling for a while or at warm up, but your guess is as good as mine(probably better)

    Anyone else have a take on this.

    I am taking the car to the tuner tomorrow, but want to get this idle issue taken care of before I drive it there.
    Even though you aren't making boost while idling, the turbos are always spooling and pushing air into the engine, even if its not positive pressure.

    That extra air could be the equivelent of having the throttle cracked open, and it doesn't take much throttle to run the engine at 2200-2400RPM with no load on it, so its very possible that the extra air from the turbos is making it idle higher. Just a guess though, the tuner should be able to figure it out for sure.

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    Member fil131's Avatar
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    Quote Originally Posted by Wesman View Post
    Even though you aren't making boost while idling, the turbos are always spooling and pushing air into the engine, even if its not positive pressure.

    That extra air could be the equivelent of having the throttle cracked open, and it doesn't take much throttle to run the engine at 2200-2400RPM with no load on it, so its very possible that the extra air from the turbos is making it idle higher. Just a guess though, the tuner should be able to figure it out for sure.
    Well that makes sense, I havent had much experience with turbos.

    My issue is that I want to drive the car about 20 miles or so to the tuner, but I dont wanna mess anything up.

    Is there any way I can tune for the idle? I have HPTuners, and have tuned for the 60#ers already.

    Thanks for your input

  6. #6
    TunedbyFrost.com Tuner Frost's Avatar
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    The turbos aren't moving any air and they sure aren't holding open the throttle or saturating the IAC, but it is fully closed.

    If you are *sure* you have no vacuum leaks, and you are running a NEW (to you) throttle body, try turning the minimum airflow screw so that the blade is closed a little more at rest position (0% throttle). If it's not that, it's certainly a leak. Make darn sure it isn't a leak or your car could end up getting tuned around it. If that happens and it gets better or worse, the car will need touching up (tune wise). Make SURE it's not a vacuum leak before you take it to get tuned. If this is your old TB and it used to idle fine at that minimum air setting, then it's almost surely a leak.

    What happens is that so much air is coming in that IAC closes all the way up trying to lower the airflow. When it reaches 0 and can limit it no more, the rise in RPMs is the result of more air.

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    Member fil131's Avatar
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    Quote Originally Posted by Frost View Post
    The turbos aren't moving any air and they sure aren't holding open the throttle or saturating the IAC, but it is fully closed.

    If you are *sure* you have no vacuum leaks, and you are running a NEW (to you) throttle body, try turning the minimum airflow screw so that the blade is closed a little more at rest position (0% throttle). If it's not that, it's certainly a leak. Make darn sure it isn't a leak or your car could end up getting tuned around it. If that happens and it gets better or worse, the car will need touching up (tune wise). Make SURE it's not a vacuum leak before you take it to get tuned. If this is your old TB and it used to idle fine at that minimum air setting, then it's almost surely a leak.

    What happens is that so much air is coming in that IAC closes all the way up trying to lower the airflow. When it reaches 0 and can limit it no more, the rise in RPMs is the result of more air.
    It is the stock unmodified TB and the car did idle fine before the install of the APS twin turbo kit and the 317 heads.

    As soon as I finished the install and topped off all of the fluids I started it up and it idled fine for a while then started to rise, and sits around 2200 to 2400.

    I do not hear any leaks anywhere, is/are there any easy ways to find a leak?

    I have put a tune in for the injectors and that is all I have done PCM wise.

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    take some carb cleaner and spray all the vacuum connections with the car running and listen for changes in the way its running, it it runs different theres your leak... check all the clamps on your boost hoses, its easy to miss one

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    Member fil131's Avatar
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    I tuned it rich to be safe and drove it all the way to the tuners shop like 20 miles away, upshifting like crazy to keep the RPMs down to not hit boost, and when I got there I opened the hood to show the tuner the work I had done and was explaining the High Idle issue and he looked around for like 10secs and said "Oh Shit" lol, your throttle is a bit open... Thats when I realized I had removed the adjustment cover on the throttle cable and had reapplied it too tight . I cant believe I made such a big thing out of something that I could have taken a little more time to investigate and notice the throttle was not touching the set screw.

    Oh well, if thats the only thing that goes wrong for me with this buildup I will be very lucky.

    Thank you for your time and patience.

    Your help is always appreciated.

    Filbert

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    The Bandit Wesman's Avatar
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    Quote Originally Posted by fil131 View Post
    I tuned it rich to be safe and drove it all the way to the tuners shop like 20 miles away, upshifting like crazy to keep the RPMs down to not hit boost, and when I got there I opened the hood to show the tuner the work I had done and was explaining the High Idle issue and he looked around for like 10secs and said "Oh Shit" lol, your throttle is a bit open... Thats when I realized I had removed the adjustment cover on the throttle cable and had reapplied it too tight . I cant believe I made such a big thing out of something that I could have taken a little more time to investigate and notice the throttle was not touching the set screw.

    Oh well, if thats the only thing that goes wrong for me with this buildup I will be very lucky.

    Thank you for your time and patience.

    Your help is always appreciated.

    Filbert
    Glad it was something simple

  11. #11
    Member fil131's Avatar
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    Quote Originally Posted by Wesman View Post
    Glad it was something simple
    So was I...

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