Constant high idle when moving off throttle..

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Jul 10, 2005 | 06:56 PM

Y2K SS

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Constant high idle when moving off throttle..

Sup guys.... did a head, intake, TB install the past weekend. Car runs great and all my LTFTs are in check. Only problem is that when I'm like rolling down a hill my car will idle at 2k until I come to a complete stop. Even when I'm cruising and just throw it into neutral it'll do it as well.Do I take care of this in the idle airflow vs. ect??

Jul 10, 2005 | 07:34 PM

Another_User

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That is because your base running airflow is too high (and/or your throttle body blade is cracked or drilled too much). Your idle trims (at least your ST, I am not 100% sure on the LT, but they move REAL slow) don't affect your base running airflow once you start moving, so you get hit with the full base running airflow table, plus throttle cracker.

Basically you need to tune your base running airflow and your TB.

Jul 11, 2005 | 11:14 AM

WS6FirebirdTA00

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yeah you gotta get all the idle air right and your effective area for the new tb, once you do this it will fix it

Jul 12, 2005 | 09:43 PM

Y2K SS

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this is the thing... the new ported tb I got has a smaller hole than the old one.

Jul 12, 2005 | 09:52 PM

WS6FirebirdTA00

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ok ive been working on a idle write up, ill post it up here in the tuning section, read it and do what it says and you will be getting a lot better.

Jul 13, 2005 | 07:35 PM

Another_User

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Quote:

Originally Posted by Y2K SS

this is the thing... the new ported tb I got has a smaller hole than the old one.

That doesn't matter. The IAC valve still opens and closes allowing metered airflow through. Also, your throttle blade can be cracked too far. The hole you see on your TB for your IAC has no impact on your IAC valve (except that it may restrict it with the valve opened all of the way, but I doubt it, and that should not be the case anyways.

Jul 13, 2005 | 08:46 PM

WS6FirebirdTA00

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if the hole where the iac is is smaller, epoxy filled, the car will be WAY off in the effective area. ive got that post up and if this is the case you can read through it on fixing it. will be a good test to see if what i put is understandable lol