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Fluctuating idle problem

Old 27-Mar-2006, 10:20 PM
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Fluctuating idle problem

b16a2. 80k. Idles high (1500-1700), drops to 1000, then shoots back up, then drops and shoots back up over and over (usually 3-4 times) and then it idles about 1200. No idea what is going on. Any suggestions?

Also, sometimes when when i beat down on the car, the idle stays at like 5000 or 6000 even when i let go of the accelerator. I can make it drop back down if if push down the accelerator a bit to make it rev a litter higher then what it got stuck at.

I already know that it is something to do with the throttle body, any suggestions as to whether it is the throttle body that is defective or whether there are specific sensors i should be looking at?

Any help would be greatly appreciated. I'm sure zeeman can figure this one out.
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Old 27-Mar-2006, 10:22 PM
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i dont know what would cause the sticking.. but your idling problem is most likely your iacv.. im pretty sure theres a thread on how to clean them around here somewhere.
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Old 27-Mar-2006, 10:35 PM
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oh, the idle adjustment screw cannot be adjusted anymore as it is on the lowest setting. Any other suggestions other then iacv?
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Old 27-Mar-2006, 11:10 PM
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the IACV is the idle air control valve, on the back of the intake manifold, honda's design is garbage and this is a super common problem. The crap out and your cars idle will fluctuate horribly. Fortunately you can steal these off of many different engines, as long as its a 2 pin iacv and has the proper sized mounting holes, some have the mounting bolt holes closer together than others.
But there are other things than can cause a fluctuating idle.
Here's an article that will help you troubleshoot:
http://www.g2ic.com/forums/showthrea...9&page=1&pp=20
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Old 27-Mar-2006, 11:39 PM
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as always zeeman comes though. thanks zeeman, i will do all that stuff tomorrow and post an update. hopefully i am successful
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Old 28-Mar-2006, 12:08 AM
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if not i know something else that it might be. Is your ecu chipped by any chance?
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Old 28-Mar-2006, 10:14 AM
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nope, using the stock p2t ecu virgin
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Old 28-Mar-2006, 09:18 PM
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i did the diagnostic process for the code i was getting (p0505) and it turns out it is teh IAC valve. So now i need to get a new one. Problem is, i am nto willing to spend 340$ plus taxes so i'm going to see if i can pick up a used one from somwhere.
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Old 28-Mar-2006, 09:22 PM
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Originally posted by civicnation
i did the diagnostic process for the code i was getting (p0505) and it turns out it is teh IAC valve. So now i need to get a new one. Problem is, i am nto willing to spend 340$ plus taxes so i'm going to see if i can pick up a used one from somwhere.
so i was right, lol

you dont need to replace it.. you can service it. Try to clean all the carbon build up outta there.. then try it.
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Old 28-Mar-2006, 10:17 PM
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i've never been able to fix an IACV by cleaning it. Just get another used one. New ones from honda are super expensive.
You can take them off a lot of different engines both b and d series.
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Old 28-Mar-2006, 10:22 PM
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well you might as well clean the carbon buildup/blockage in the passage.. it doesnt hurt to try before you go out an buy another one, i've never had a problem with one so I wouldn't know how much the cleaning would do.
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Old 28-Mar-2006, 10:48 PM
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true true, cleaning it won't hurt, but prolly won't fix it....but its worth a shot, it doesn't cost anything to clean it.
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Old 28-Mar-2006, 11:08 PM
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does anyone know where i can find a used one? i just cant seem to source one
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Old 28-Mar-2006, 11:09 PM
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i will try to clean it tomorrow. if i just unbolt it from the IM and spray some throttle body cleaner into it, should that be enough? is there a specific way to clean it?
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Old 29-Mar-2006, 12:05 AM
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take the coolant lines off and unplug the electrical connection and remove it from the manifold. Then spray lots of brake cleaner/carb cleaner/whatever into the holes and let it soak for a good while, then dump it out, spray a little more in there to makes sure all of the shmegma is out and spray a little compressed air into it to blow all of the crap out and help it dry.
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Old 29-Mar-2006, 12:06 AM
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i've got a few IACV's that will fit if you really need one, i don't usually like to get rid of them b/c i've been through a couple on my car already and just know as soon as i get rid of one, i'll end up needing one myself.
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Old 29-Mar-2006, 12:15 AM
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Smile

thanks a lot zeeman, i really appreciate the offer. I will try my best to clean it and if that still fails i'll continue to try to find one used from somewhere around me. I will definitely let you know if all else fails. Again, i really appreciate the offer
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Old 29-Mar-2006, 01:18 AM
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i had the exact same problem and i had the error for the idle air valve aswell.

however there were multiple problems that contributed to this...

1 was the intake manifold gasket had a tiny hole
2 the iacv was ****ed
3 one of the vacum lines were off (the tiny tube one)

unlike andrew (zeeman) i was completely sucessful at fixing the iavc all i did was take it apart completely and clean it up.

what you have to know is that when u clean it up its not enough just to spray carb cleaner and let it soak as it will do nothing. you have to make sure that the plate inside spins freely with no form of sticking.

i installed it back and replaced the gasket and hooked the vacum line up and also cleaned the throttle plate and it was mint.
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Old 29-Mar-2006, 01:38 AM
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sick, thats good to hear Jay. Maybe now i can fix the pile of busted IACV's i've got here.
Having a leaky intake manifold gasket and a vacuum line disconnected, in conjunction with a malfunctioning iacv would definately cause the car to run like how you explained to me over the phone. Glad you figured it out. So you have to take off the plate with the coolant nipples on it to access where you really need to clean? Good job figuring out how to clean these suckers. I'm gunna try and see if i have any luck cleaning them how you do.
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Old 29-Mar-2006, 07:02 AM
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so there is a plate where the coolant nipples attach that can be removed?
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