What is an idle air control?

Answer 1

Here is a run down as far as i understand it. I have only a cursory knowlege of the throttle system in a late 90's early 00's Ford, and i am sure that the systems vary, but i would assume that the basic premise is the same.

inside the throttle body (past the air cleaner and before the air intake) there is a plate that hinges on a rod that runs down its center. there is a cable and a pair of springs on the side of the throttle body that make this plate either hinge open to let air through or close to shut the air off from your engine. When you depress your gas pedal, the cable on the side opens the throttle plate to allow air to pass through and mix with the gasoline for the proper consistency and temperature for burning. (for this reason, calling it a gas pedal is a misnomer, it is much more of an air pedal)

When you release the gas pedal, the springs on the side allow the throttle plate to swing back closed, thus blocking the flow of air into the engine. However, even at idle, your car needs air to flow with the gasoline, so there is a valve there which bypasses the throttle to let small amounts of ari in to burn with the gasoline. This is the idle air control valve.

The symptoms i have seen with this issue are a sputtering at idle, which means that the valve is not opening as far as it should. I have also hear that the valve stays too far open, which causes the idle to run extremely high.

If you are experiencing a faulty idle air control, there are a few things to check. First, go to www.autozone.com and look up the idle air control valve to ensure that you know what you are looking for. Next, follow the big rubber hose from your air filter until it runs into a metal piece with a cable and 2 springs on it (yep, that's the throttle body). You should see the idle air control valve on top (or at least nearby) the air intake (which is right past the throttle body).

There is an electrical connection there on the air control valve. while your car is idling, disconect it. if the idle changes, than the valve and the solenoid that controls its actions are not burnt out. plug it back in, and turn off your car.

If the idle did not change, go to your local parts store and buy a new one, mine ran about 50 bucks. Put it back in, making sure to get rid of any old gasket material and securing it tightly. disconnect your negative (black) power cable from your battery, let it sit for a few mninutes, re-connect the btter cable, start up your car, let it idle for about a minute, then take it out for a drive. It should take about 25 miles of combined city and highway driving for your car's computer to learn how to run again, kind of feeling out all it's new fancy stuff.

If the idle did change, go to your local parts store and buy a few things...throttle body cleaner, a throttle body gaskets, and idle air control gaskets. Make sure you have some metal wire to clean out ports, and a whole mess of paper towels to soak stuff up with.

Take off the throttle body, being very careful not to stretch out the cable or springs on he side. clean it (also a great time to clean your egr passage, ford owners!!!) and wipe uo all the drippy stuff.

take out the iac valve....here's the tricky part. THat section at the back of the valve that is a different material is the solenoid that forces the valve open and closed. Do not, under any circumstances, get throttle body cleaner into that part!!! clean out the 2 openings on the valve, and make sure the little plunger opens and closes properly (don't be forceful with it!).

Once it is clean, re-attatch everything, reattatch your neg. battery cable, and follow the above instructions to reset your idling perameters.

You have now fixed your idle problem.

PS. You'll learn all of this if you ever have an EGR problem.