Idle goes up and down! HELP!

EK Devil

New Member
5+ Year Member
My civic just started to do that about a few weeks ago and I'm trying to figure how to fix the problem...when the car warms up and when i come to a stop light, it idles up and down....how do i fix that? and where is the IACV and idle screw located at? pics will be helpful. thanks
 

EJAaron

New Member
5+ Year Member
maybe you have a vacuum leak somewhere
 


Flatblack-Hatch

New Member
5+ Year Member
It sounds like an ics (idle control sensor) problem. the screw to tune it should be right on the throttle body.
 

Kay@NHT

New Member
5+ Year Member
yea i would say IACV you can pick one up cheap ... i remember seeing a DIY clean it out online let me see if i can find it for you
 


haftahonda

New Member
5+ Year Member
sometimes its just low coolant or also a coolant temp sensor. do you have a check eng lite?
 

89y49rexsi

twinke team bio
5+ Year Member
sometimes its just low coolant or also a coolant temp sensor. do you have a check eng lite?
x2
check your coolant sensors the one you need to check is the 2 pin under the dizzy
also what motor do you have if its the dual point then i have no idea cuz i hate that motor myself
but if its a d16a6 then i beleive the screew that you would need to tighten is on the bottom of the throttle body

too bad its not a b16 i know that s**t inside out lol
 

fusion

New Member
5+ Year Member
depending on the motor you have you can either have a rotary or a linear IACV. If its a rotary you are screwed and there is no way to clean it. A rotary IACV will be greenish in color and mount on the backside of the intake manifold and youll understand what i mean by rotary when you pull it off. however if you have a linear IACV, it will be located on the backside of your intake manifold held on by 2 bolts. Just pop it off, spray it down with some Simply Green, let it dry, mount it back up and your car will stop surging.
 

kwell

New Member
5+ Year Member
idle set to high... thats what i say but i havent had a iacv in a long time
 

copliesflip

New Member
5+ Year Member
My car has a very similar problem. I have a EG8 with the stock d15 and when i start it up the idle goes up to about 3,000 rpm and then after awhile it will go back down to around 2,000 to 1,500 rpm. I followed the procedure to adjust the the idle speed with the screw but as soon as it starts to drop something causes the idle to go up so that it stays at 1,500 rpm. What should I do next? I looked at the local Honda dealer and auto parts store and they want like $200 for the IAC valve and i dont want to pay that, especially if im not sure that is the problem.
 

dahansen2000

New Member
IACV repair

As a car dealer I've had several Civics that had the idle go high and then low after being warmed up. The latest was a 97 Civic DX. To solve the problem, I removed the throttle body, removed the IACV from the throttle bottle, then I unscrewed both ends of the IACV. With the shaft exposed, I was unable to easily rotate the shaft. I sprayed some Powerlube on both ends and worked the shaft back and forth by hand. After a while it freed up with just a little resistance. I replaced the end pieces and then reinstalled the throttle body. It had one up and down cycle, and then settled in and idled perfectly. It was quite a relief to solve the problem so inexpensively. Before doing this I had replaced the IACV with another one I had from another engine. It did the same thing. This, I would guess, is a common problem, especially with engines that may sit for a while unused, which both of these engines had.

DH
 


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