IAC TEST???????/
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Honda-Tech Member
Joined: Feb 2003
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From: SoCal
IAC TEST???????/
i heard about a test u can do to check if the IAC is messes up. my car idle surger from 1000-1500, what are the tests, i heard of one where u plug a hole in the TB and if the car doesnt stall then u have a vacuum leak, but what if the cars stalls, or worse the car dies. what does that mean.
the reason i ask is because when i plugged it the car died.
the reason i ask is because when i plugged it the car died.
Honda-Tech Member
Joined: Jan 2004
Posts: 240
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From: Cali Life Style, usa
Re: (S.Convoy)
usually when your car does that, it is caused by a valve that goes under neath your throttle body, where the water hoses hook up to. I am not sure if you can fix it, but I replaced mine. Mine used to do that idling crap, but then that fixed it
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Joined: Dec 2001
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From: Saint Paul, MN, USA
Re: IAC TEST???????/ (ConvoyPMR)
I'm not too familiar with the IAC on a Honda. But I'm assuming they're all the same..
The test you're talking about, I believe has to do with blocking the hole where the IAC itself plugs. To do this, (assuming you have the intake off) I would first unplug the wiring to the IAC. Next I would take my finger and plug the hole where the IAC is. Next, rpm should drop. If not, I would then power up the IAC and see if it works.
If the IAC works fine and nothing is wrong with it, I would plug in a Scan Tool next. I then would look at the IAC counts. But if the IAC doesn't work, that's your problem.
If there's a High Count, say above 25, I would assume that the PCM wants the engine to idle fast. If that's the case, I would look at the ECT and see if it reads hot. If not, the ECT may be skewed and the PCM thinks that the engine is cold thus you get a fast idle..
But now if the ECT is hot, I would then look to see if there's a load on the engine. For example, if the Power Steering Pressure switch is ON even though you're not moving the wheel, the PCM would adjust idle. Or maybe the AC Request is always on even though you don't have it running. Anything that causes a load on the engine, the PCM will anticipate it and adjust the idle speed accordingly..
I hope this helps. It would be a lot easier with the car infront of me.. But good luck..
The test you're talking about, I believe has to do with blocking the hole where the IAC itself plugs. To do this, (assuming you have the intake off) I would first unplug the wiring to the IAC. Next I would take my finger and plug the hole where the IAC is. Next, rpm should drop. If not, I would then power up the IAC and see if it works.
If the IAC works fine and nothing is wrong with it, I would plug in a Scan Tool next. I then would look at the IAC counts. But if the IAC doesn't work, that's your problem.
If there's a High Count, say above 25, I would assume that the PCM wants the engine to idle fast. If that's the case, I would look at the ECT and see if it reads hot. If not, the ECT may be skewed and the PCM thinks that the engine is cold thus you get a fast idle..
But now if the ECT is hot, I would then look to see if there's a load on the engine. For example, if the Power Steering Pressure switch is ON even though you're not moving the wheel, the PCM would adjust idle. Or maybe the AC Request is always on even though you don't have it running. Anything that causes a load on the engine, the PCM will anticipate it and adjust the idle speed accordingly..
I hope this helps. It would be a lot easier with the car infront of me.. But good luck..
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