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Discussion Starter #1
My car has had a rather interesting idle surge problem for four years: It only surges with the A/C on, and typically when ambient temps are "warm".
It well never surge/search/bounce or attempt to kill the engine otherwise and it's completely reliable.

But, hot seasons are long here and I'm getting tired of the idle problem for 5 months of the year.


IACV seems most probable, but the third party parts are still ~$180, and I'm weary on used parts.
Anybody have any experience with these aftermarket or possibly a used Honda? Did it work perfect and fix the problem?



Thank you very much.
 

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Discussion Starter #3
Yes, I "tried", as in I looked up the best guide online I could find, grabbed proper cleaners and a new gasket/screen. It literally didn't change a thing.

The caveat? I highly question my knowledge of the part and therefore my ability to properly clean or disassemble the part(which I hardly did).


Any guidance? (have a spare vehicle I could use while I have it off of the car for a day or two if need be)
 

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Yes, I "tried", as in I looked up the best guide online I could find, grabbed proper cleaners and a new gasket/screen. It literally didn't change a thing.

The caveat? I highly question my knowledge of the part and therefore my ability to properly clean or disassemble the part(which I hardly did).


Any guidance? (have a spare vehicle I could use while I have it off of the car for a day or two if need be)
Have you cleaned your EGR ports? Mine had similar problems but after cleaning the EGR ports they were helped quite a bit. Certainly not fixed as it will still drop down a bit low after revving up a bit on a hot day. Just something to think about before dropping the money on an IACV. I am likely going to purchase an OEM one soon to try and rectify the last bit of my minor idle drop.
 

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You can narrow down your problem somewhat by taking off your intake and having a look inside your throttle body. Towards the firewall side of the throttle body there are two ports, the one on the top is connected to the IACV and the lower is connected to the FITV. When your car is warmed up and actively has the idle issue, you can cover the IACV hole with your finger and see if the problem goes away. If it goes away its obviously related to the IACV.

The same could be said for the FITV.

And like others have said, there is a screen that can get all clogged up on the IACV that can cause it to malfunction, its quite easy to clean or replace. Always check for vacuum leaks to, it is quite easy to accidentally disconnect one of the vacuum lines going into the intake manifold when doing oil changes and other routine maintenance.

I recently replaced mine with a used one off of ebay after dealing with the surging and bouncing idle problem for awhile, mine eventually got to the point where it actually threw a code for the IACV even though it was completely clean, they can be had off of ebay used for pretty cheap.
 

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Discussion Starter #7
Have you cleaned your EGR ports?
The motor was not installed when I bought the car, and the ports were fully cleaned while the motor was out. The idle problem occurred as soon as the A/C was working, or at least a very short time thereafter.

...have you bled your coolant in the past four years?
No I have not, it leaks through a leaky drain plug and/or faulty rad cap, so it gets filled every couple of weeks.
I have not really thought of that as a problem, but if there are constant air pockets around the IACV, that could definitely be a source!
Great idea, thank you.

I will more seriously pursue a fix to the leaks so I can bleed it and be sure that's not a problem.




I really wonder what exactly wears out...what mechanical parts lie within the IACV. I assume there must be some type of piston or something...???


Thank you very much, everyone.
 

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Discussion Starter #8 (Edited)
G-wiz, that test sounds too good to be true, too easy. I will try that as soon as I possibly can, probably tomorrow. I have never heard of that procedure, thanks very much for the info nonetheless!


What is the purpose of an IACV if you can fix the problem by plugging a hole that ceases its effect altogether?
 
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