IAC Valve
Yeah it was dirty and i know i didnt adjust the stop screw. I sprayed carb cleaner in the iacv holes like a whole can haha. And scrubbed with a tooth brush. Short of taking the TB off i cleaned everything. I havnt drove it since i scrubbed the plate and everything thou. But somedays it runs and idles good and others its really crappy. Idk why its really bothering me. I might try removing the idle screw and cleaning it too im almost out of options i have another TB i ready to remove mine and try that one but thats kinda a big project
After cleaning it all out, you've disturbed the air flow rates, etc. On top of the system being misadjusted by the previous owner. I'd expect it to act flaky until you set the base idle, reset the ECU, & have it re-learn the idle. Couple threads about idle right now, but I just realized I didn't send you over to read this link...
https://www.hondaaccordforum.com/for...e-speed-38734/
You shouldn't assume whether its fixed or not, based on surging behavior. Go through that procedure THEN you'll know if you have more work to do.
https://www.hondaaccordforum.com/for...e-speed-38734/
You shouldn't assume whether its fixed or not, based on surging behavior. Go through that procedure THEN you'll know if you have more work to do.
Okay ill do this tomorrow. The book never told me to let it conpletly cool down or turn the radio off or blowers. Let it sit till the block is cold again? Maby that was my problem i never let it cool down or turned off the radio. Should i turn the screw in almost the whole way cause its pretty far out from me trying to set it before cause previous owner had it all messed up. Or just leave it and adjust it from where it is
Once it's all warmed up, you unplug the wire from the IACV and that will make the idle drop - you already said that. If it doesn't stall, just adjust it from there to get 550 rpm.
THEN let it cool off. After you reset the ECU, it "learns" the idle by warming up IF YOU DON'T TOUCH THE GAS PEDAL.
There's a few (less common) things if it still doesn't work. Most times the IACV is OK; just dirty or fighting against a mis-adjusted throttle body. Occasionally the IACV operates sticky, not smooth, and won't clean out properly. Sometimes you just have to buy a new IACV but I like to rule out the adjustment stuff first.
THEN let it cool off. After you reset the ECU, it "learns" the idle by warming up IF YOU DON'T TOUCH THE GAS PEDAL.
There's a few (less common) things if it still doesn't work. Most times the IACV is OK; just dirty or fighting against a mis-adjusted throttle body. Occasionally the IACV operates sticky, not smooth, and won't clean out properly. Sometimes you just have to buy a new IACV but I like to rule out the adjustment stuff first.
Check the lower port in your throttle body. When you stick your finger over it, the idle should drop. If you cant adjust your idle at the throttle body, your IAC is shot. I would also check for vacuum leaks at the intake manifold & for a blocked air assist hose. This can be checked with a vacuum gauge. If you "T" into the air assist hose, the vacuum should not be more than 40kPa.
Also....you should only need to adlust the idle control 2-3 turns from fully closed.
Also....you should only need to adlust the idle control 2-3 turns from fully closed.
Last edited by kiwibilt; Apr 19, 2012 at 11:24 PM.
You said that your check engine light is turning on. What code(s) are you getting?
If you go to the common diy thread on top of the gen tech help forum, there is a link on how to check engine codes.
If you go to the common diy thread on top of the gen tech help forum, there is a link on how to check engine codes.
No i have no codes. It only comes on when i disconnect the iacv..... And ill get a vac guage today and start checking hoses what are common ones to check first
If the base idle is set too high, for example the base idle is set for 750 instead of 550, then the IACV will close itself off when it's plugged in and operating. In that case, when you unplug it, it's already closed so the idle doesn't drop. In that situation, the IACV is NOT necessarily bad.
I might be getting confusicated between 2 different people asking about IACV and surging idle. I thought you had said that the idle DOES drop off when you unplug it.
In any case, adjust the base idle to 550 & go from there.
I might be getting confusicated between 2 different people asking about IACV and surging idle. I thought you had said that the idle DOES drop off when you unplug it.
In any case, adjust the base idle to 550 & go from there.
If the base idle is set too high, for example the base idle is set for 750 instead of 550, then the IACV will close itself off when it's plugged in and operating. In that case, when you unplug it, it's already closed so the idle doesn't drop. In that situation, the IACV is NOT necessarily bad.
In any case, adjust the base idle to 550 & go from there.
In any case, adjust the base idle to 550 & go from there.


