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View Full Version : IDLE Issues SURGES, etc - IACV Cleaning - Understanding



Omasta
31-10-2018, 01:53 PM
(I posted this earlier as an extension of a previous question I asked - then solved, however this may be easier for others)

Despite common perceptions the Honda IACV component is not one that regular fails - becomes dirty yes, fails no; this is primarily due to the simplistic design.

Basically the IACV contains a small electro Magnetic Valve that Slides back and forth - opening and closing to allow the flow of coolant based on engine demands. this Valve can become blocked - consider it similar to the build up of calcium in a shower head. the build up of sludge sticks to both the inner chamber and the slider. over time the slide cannot close.

The surging thus caused is usually a process of this; (DONT Quote me - there is a chance I wrote it backwards - but the process is accurate)

Engine heats up, slider Valve activates. Slider however cannot close/open properly due to sludge/blockage - this failure causes the engine to surge, when the engine revs move beyond a certain point the slider attempts to activate again, closing/opening the flow enough to cause a drop in revs but an inability to complete the process hampers this and it becomes circular. the car is continually trying to close/open to finish the process. each failure requires another adjustment elsewhere involving air, fuel etc.

To solve this you need to remove the throttle body as shown here

http://www.ozhonda.com/forum/showthread.php?110641-D16y4-IACV-Clean-and-Throttle-body-removal-Revs-hunting-Look-here

1. you then need to remove the IACV from the throttle body.

if you look closer you can see the "tongue" of the valve slider section. that needs to glisten. with my IACV I removed the electromagnetic component - be AWARE there is a glued seal underneath, it WILL become a little damaged however this is predominantly related to keeping moisture out - I havent researched if it can be bought - however there are types of glues that are able to make those sort of tiny "gaskets".

1b. removing the Electromagnetic component allows you to slide it back and forth - with my IACV it would NOT move, it had that much sludge.

2. you need to clean the IACV chambers and slider with Carb Cleaner, perhaps a toothbrush and tiny cotton buds.

3. when it shines, then reassemble. (I am NOT certain about the distance the slider tongue needs to be before the controller side is added again - i took a photo and ensured it was the same gap. there is a chance that the controller side has a specific range.) The magnet will SNAP back in place when the controller is added.

4. reassemble the Throttle Body etc, put your car back together.

My car run smooth as new.

For extra info, look here. Explains the Electro/mechanics

http://www.fuelly.com/forums/f10/more-than-you-ever-wanted-to-know-about-the-honda-iacv-7495.html