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Prelude Idle Air Control Valve Bypass Procedures

NOTE: This is a disclaimer saying that I'm not responsible for any damage caused to you, tools used, your car, your mother ,hamster, or anything else for that matter. I have not tested this mod in temperatures under 40 degrees F. If you can please let me know how the engine reacts to freezing temperatures. This mod is something that you choose to do at your own risk. With this aside good luck have fun and I hope it helps you.

Does your prelude idle fluctuate up and down? Chances are your Idle air control valve has gone bad. There is a quick and free way to bypass this with some simple steps below:

How to Check if your Idle Air Control Valve is bad

Start the engine.. let it warm up to normal operating temperature. With the engine running at idle, take off your intake place your finger over the lower port hole in the throttle body (See Picture below and notice the lower hole on the left side of throttle body)

Click to Enlarge any picture

By placing your finger over the lower port, does the idle return to normal? and is the lower port sucking air? If so then you need to do this mod.

If your Idle Air Control Valve is bad / not working lets begin:

  • Remove the four bolts holding the throttle body on.
  • Remove the three bolts holding the idle air control valve on (Be careful not to damage the seals)
  • Unscrew the valve from the housing
  • Take the valve apart - by unscrewing counter-clock-wise
  • Your going to need to reverse the spring and the clip, so take off the metal plate holding the spring, take the spring off, and turn the metal plate backwards
  • Put the spring in the housing first, then screw the valve back in w/ plate reversed to catch on spring. Do not overtighten, just tighten till its closed.
  • Your valve should now look like mine with it closed, if not check that the spring is on the plate properly. Notice the slight bend in the spring now that its assembled, pushing the valve closed.
  • Put the seals back on the valve and put it back together with the three bolts
  • Screw the throttle body back on, and you're done!

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Page Modified: June 24, 2007
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