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    Sunday, October 07, 2012

    DIY: Idle Air Control Valve

    Someone once said, "when you're poor, your save money and pay for it in time. When you're rich, you'll save time and pay for it in money."

    Well I'm poor.

    Lately my 1994 Honda Accord (4 door LX 4 cylinder) has been idling low - I mean really low - somewhere around 300-400 RPM. Besides the incredible shakes that make you think it will die at any minute, it has started dying as I back out of parking spaces. This problem happened when the engine is warm - starting in the morning with a cold engine got a decent response until the radiator fan came on.

    Unable to pay for someone to diagnose and fix this for me, I scoured the internet. I found this post on Honda-Tech.com. People smarter than I had ran into the same problem.

    **Now, sometimes all you need to do is turn the idle control screw on top of the throttle body and adjust the idle speed, but I figured my problem was deeper than that given my car's 260K + miles.

    This post described how to clean your Idle Air Control Valve (IACV) which adjusts the amount of air let into the engine (if I understand it correctly). A clean IACV gives you better idling RPM and more fuel efficiency.
    I'm not going to recreate the excellent "How-To" on Honda-Tech.com, but I will give you some thoughts.

    There it is waaayyy in the back
    A closer view
    On opening the hood, I spotted the IACV well in the back. This made it incredibly difficult to get to - especially from someone like myself who's passably good with tools but not even remotely experienced with cars.

    Yes, that's a battery

    First, I disconnected the battery because 1. electricity runs through the IACV and you need to reset it after cleaning it, and 2. I don't want to die.

    Darn black tube in my way
    Ah! Much better!
     Second, I had to take the top off the air filter and disconnect the intake manifold.  I tried for too long to disconnect the IACV without doing that, and I couldn't reach it. It's WAY too crowded and small back there. Taking that big black tube out of the way made it MUCH easier.

    Soiled shut

    Once I got it off, I easily saw how right I was about the etiology of my problem.

     I bought IACV cleaner from Autozone (although I've read that Carburetor cleaner would work fine .. don't know if there's even a difference) and this is what it looked like afterward (O-ring removed during cleaning so it wouldn't get damaged. Don't forget to put it back in!).

    After putting it back in, I almost didn't check the radiator fluid. The resevoir was almost dry, because of the lost fluid from the tubes that run through the IACV. Topped it off after another trip to Autozone, and it's idling at 750 RPM like a champ!

    The whole experience was awesome, because I realized I can fix a car without breaking it more, I saved tons of money, and it reminded me again how similar car repair is to surgery - without the malignant residency to go through...