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  1. Join Date
    Sep 2013
    Posts
    153
    #1
    Hi,

    I would like to ask, is the device responsible for the control of air during idle the same when the AC is on or off? I noticed that when my AC is on, sometimes the RPM goes down then eventually returns to normal(in my case 800rpm) but when the AC is off, it is consistently in 800rpm. When I try to rev my engine, the RPM goes down up to 100-200rpm then goes up to normal again. Would like to know if this is connected with the IACV?

    Thanks!

  2. Join Date
    Sep 2012
    Posts
    2,809
    #2
    May idle up solenoid na dapat mag kick in once you turn on the aircon.

    Two types ito meron... yung isa is hiwalay ang assembly ng idle up while meron din naman na naka built in either sa carb or controlled by computer box via IACV

  3. Join Date
    Sep 2013
    Posts
    153
    #3
    Quote Originally Posted by jodski View Post
    May idle up solenoid na dapat mag kick in once you turn on the aircon.

    Two types ito meron... yung isa is hiwalay ang assembly ng idle up while meron din naman na naka built in either sa carb or controlled by computer box via IACV
    Salamat Sir jodski. So basically, iba nga ung nagconcontrol ng idle kapag on and off ung AC. Would you have any idea kung anu ung sakin, Civic 97 LXi ung oto ko.

  4. Join Date
    Oct 2009
    Posts
    2,271
    #4
    Quote Originally Posted by mark_celiz09 View Post
    Salamat Sir jodski. So basically, iba nga ung nagconcontrol ng idle kapag on and off ung AC. Would you have any idea kung anu ung sakin, Civic 97 LXi ung oto ko.
    nandun yan sa intake manifold malapit dun sa throttle mismo..servo motor.

    minsan kung wala sa timing ganyan ang honda.palit ng air filter mura lang naman un nasa 200.saka mo pasilip sa timing gun ung timing.
    or baka madumi nadin ung throttle mo..

    nagka ganyan nadin ung tsikot ko.kaso vti ung sa akin.

  5. Join Date
    Dec 2009
    Posts
    986
    #5
    Quote Originally Posted by mark_celiz09 View Post
    Hi,

    I would like to ask, is the device responsible for the control of air during idle the same when the AC is on or off? I noticed that when my AC is on, sometimes the RPM goes down then eventually returns to normal(in my case 800rpm) but when the AC is off, it is consistently in 800rpm. When I try to rev my engine, the RPM goes down up to 100-200rpm then goes up to normal again. Would like to know if this is connected with the IACV?

    Thanks!
    the aircon is an additional load to the engine... if you turn it on, the engine should increase its idle to compensate for the additional load.
    to achieve a higher idle, engine speed should increase,

    to increase engine speed, additional air(more air more power) must enter the engine through the intake tract.

    to supply additional air into the engine, there are many ways
    1. through the use of an air pump, air is force fed to the intake tract
    2. through a vacuum supply, a gate can open or close a hole which can help additional air to enter (engine creates suction/vacuum)

    so when you turn an aircon, additional air will be supplied by the "idle up control system"--- your RPm should increase, and "not decrease"

    if it doesn't increase but instead remain at the same level or otherwise decrease all together, there is something wrong with your idle up mechanism(IACV).

    usually sir it will the a solenoid(switch) / or an air pump, or a loose vacuum hose/ misrouted vacuum hose/ clog hose that causes the problem.

  6. Join Date
    Mar 2024
    Posts
    4
    #6
    When the air conditioning system is activated in a vehicle, the airflow for the engine is typically controlled by a combination of factors. Primarily, the engine control unit (ECU) adjusts the engine's idle speed to compensate for the additional load placed on the engine by the air conditioning compressor. This adjustment ensures that there is sufficient power to drive the compressor and maintain the desired cooling effect inside the vehicle cabin. Additionally, you can learn more about AC on this page modern vehicles often employ electronic throttle control systems that can modulate the airflow into the engine to maintain optimal performance and efficiency even when the AC is running. Overall, a sophisticated interplay of engine management systems ensures a seamless operation of both the air conditioning and engine functions, providing comfort for passengers while maintaining the vehicle's performance.

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What controls airflow for the engine when the AC is on?