Idle control
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Senior User
Joined: Feb 2000
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From: Connecticut
Idle control
Some time ago on this post someone mentioned a component that could be purchased through Ford that allows adjustment of the minimum airflow through the IAC, with a needle valve I believe. It is supposed to help with rough idle problems. This is for a 89 F150 with 5.0L. Any help appreciated.
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mjb1962(No Email Addresses In Posts!)
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mjb1962(No Email Addresses In Posts!)
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From: NorCal
Idle control
[font size="1" color="#FF0000"]LAST EDITED ON 13-Feb-01 AT 11:24 AM (EST)[/font][p]I believe the part you're looking for is F2PZ 9F93 9A . I was quoted $19.10 and my dealer carries them in stock. The kit is supposed to have a plate that mounts under the air bypass valve, longer screws, labels, gaskets & instructions. The plate has 2 adjustment screws that allow you to adjust the amount of extra air that gets bypassed.
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Idle control
Man, I looked all thru my notes and can't find the part #. Its here somewhere.
Threw it on my 300-6 and it made a difference in idle quality. Came w/instructions and allen wrench for adj.
Suggest there be no vac leaks and your TB should be clean(you have to take it off to do a thorough job).
I'm sure if you get a decent Ford parts guy, he'll know about it or can find it on his computer/microfiche.
Danny
Threw it on my 300-6 and it made a difference in idle quality. Came w/instructions and allen wrench for adj.
Suggest there be no vac leaks and your TB should be clean(you have to take it off to do a thorough job).
I'm sure if you get a decent Ford parts guy, he'll know about it or can find it on his computer/microfiche.
Danny
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From: Virginia
Idle control
What is the theory behind this part you are adding? I often
wondered about the whole throttle body setup. The computer
tries to keep the engine at a certain rpm at idle right? If you adjust the throttle cable stop, affecting the throttle butterfly closed position, wouldn't this move the idle air bypass valve postion?
If you closed the throttle body more, wouldn't the bypass valve open more to try to maintain the computer's set idle speed? This would also affect the output voltage of the throttle position sensor which would affect trans convertor lockup among other things? If you add something else in the picture, where
do you start?
wondered about the whole throttle body setup. The computer
tries to keep the engine at a certain rpm at idle right? If you adjust the throttle cable stop, affecting the throttle butterfly closed position, wouldn't this move the idle air bypass valve postion?
If you closed the throttle body more, wouldn't the bypass valve open more to try to maintain the computer's set idle speed? This would also affect the output voltage of the throttle position sensor which would affect trans convertor lockup among other things? If you add something else in the picture, where
do you start?
Senior User
Joined: Dec 2000
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Idle control
the idle air control valve really doesn't control the idle, but helps control the mixture at idle. The idle speed is detirmined, like in any car, by the position of the throttle plates. The IAC merely lessens any fluctuations in air volume that would pass through the throttle body. The computer has an idle speed in mind, but it really can't control it. (my idle can vary from 575-750 depending on factors outside of the load on the engine.)
The important thing to remember is that in a modern fuel injection system, it's hard to find ONE thing that controls ONE operation. Multiple sensors and acctuators go into achieving one operation. If you really want a good book to read, pick up "Ford Fuel injection and electronic engine control" ISBN# 0-8376-0301-3. 400 pages of fuel injection goodness...
hope my rambling helped...
1989 F-150 : 5.0, shorty headers, Flowmaster cat-back, K&N filtercharger intake, March pulleys, "Multi-brand" performance ignition, soon to be Mass-Air...doesn't know she's not a Mustang
The important thing to remember is that in a modern fuel injection system, it's hard to find ONE thing that controls ONE operation. Multiple sensors and acctuators go into achieving one operation. If you really want a good book to read, pick up "Ford Fuel injection and electronic engine control" ISBN# 0-8376-0301-3. 400 pages of fuel injection goodness...
hope my rambling helped...
1989 F-150 : 5.0, shorty headers, Flowmaster cat-back, K&N filtercharger intake, March pulleys, "Multi-brand" performance ignition, soon to be Mass-Air...doesn't know she's not a Mustang
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Idle control
>the idle air control valve really
>doesn't control the idle, but
>helps control the mixture at
>idle. The idle speed is
>detirmined, like in any car,
>by the position of the
>throttle plates. The IAC merely
>lessens any fluctuations in air
>volume that would pass through
>the throttle body. The computer
>has an idle speed in
>mind, but it really can't
>control it.
The IAC valve allows air to bypass the throttle plate. The ECA varies IAC duty cycle to control the idle speed. The IAC has no effect on the air/fuel mixture. Mixture control is achieved by varying the injector pulse width.
>doesn't control the idle, but
>helps control the mixture at
>idle. The idle speed is
>detirmined, like in any car,
>by the position of the
>throttle plates. The IAC merely
>lessens any fluctuations in air
>volume that would pass through
>the throttle body. The computer
>has an idle speed in
>mind, but it really can't
>control it.
The IAC valve allows air to bypass the throttle plate. The ECA varies IAC duty cycle to control the idle speed. The IAC has no effect on the air/fuel mixture. Mixture control is achieved by varying the injector pulse width.
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Joined: Dec 2000
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Idle control
guess I need to go read that chapter again...
1989 F-150 : 5.0, shorty headers, Flowmaster cat-back, K&N filtercharger intake, March pulleys, "Multi-brand" performance ignition, soon to be Mass-Air...doesn't know she's not a Mustang
1989 F-150 : 5.0, shorty headers, Flowmaster cat-back, K&N filtercharger intake, March pulleys, "Multi-brand" performance ignition, soon to be Mass-Air...doesn't know she's not a Mustang
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Joined: Jul 1999
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Likes: 4
Idle control
In addition to what Knuckles added , the Part in question was originally designed for throttle bodies that werent supposed to be cleaned or have any chemical agents to clean them due to a coating on the inside of the throttle body which was supposed to keep them from accumulating any carbon deposits . If the idle speed control is clean & the throttle plates are clean then the idle should be within specs . Often times if the throttle plates & or the idle speed control have not been cleaned for an extended period then they require extensive cleaning / carbon removal for them to operate as they should .
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Senior User
Joined: Feb 2000
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From: Connecticut
Idle control
True, you are fighting the software idle speed regulator in the computer but the idle speed at times is too low and somewhat rough. I am thinking that this additional airflow at idle will prevent the controller from dropping the idle speed so low. It will also leave the throttle valve cable adjustment to the auto transmission unchanged.
Thanks for your help
Mark
mjb1962(No Email Addresses In Posts!)
Thanks for your help
Mark
mjb1962(No Email Addresses In Posts!)
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Joined: Feb 2001
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From: Bay City, MI
Idle control
Speaking of IAC valves, someone mentioned to me that i need to clean mine (89 5.0) to stop the surging when first running in the morning. Could someone tell me how to go about doing this?
thanks, tom
thanks, tom
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