slk08

So recently my friend helped me clean out my throttle body on a 00 civic si. After i drive the car around for about 5-10 mins my car which usually idles at 700-800 rpm goes up to 1500rpm.
It actually keeps going up and down between 1000-1500rpm and while i drive my car starts acting funny like a lot of shaking. My friend told me that was probably because some air got into the coolant system.
So today i tried to bleed the air from the coolant system and after 20 min of not being able to find the bleed valve i read that there is another way which was to leave the radiator cap off while you warm up your car so that all the air bubbles will come out.
I did just that and took it for a drive.There is no more shaking when i drive but what i noticed was that whenever the car is moving the rpm will stay at 1500rpm even in neutral. It is only after 1-2sec after i make a full stop does the car idle at 1000rpm. So im stuck wondering Is there still air in my system?
Can someone tell me where the air bleed valve is at on a 00 civic si? or what else could be causing this problem and how to fix it? thx

jonlovesuti

I can't imagine having air in the coolant system would cause your idle to run high like that.
does it idle high at startup?
does it idle high after engine running for 5 minutes (sitting still)?

slk08

when it first starts up cold it usually idled at 1500rpm until it was warm then it gets to around 700-800rpm but now its more like after warming up it idles at 1000rpm but when the car is moving like going down hill even on neutral it idles at 1500rpm.

Does anyone know where the air bleed valve for coolant is on a 00 civic si? I googled it but i havent had any look finding it. Someone said its on the thermostat housing but i cant find it. Does anyone have a diagram or picture of where it is?

Former User

Check whether the throttle cable is adjusted too tightly. There should be about 1/2" free play in the cable at the throttle body.

slk08

would that really cause the idle to jump back and forth? ill try that in the morning when the suns out again.

D Griff

I don't think air in the coolant has anything to do with idle speed..

my car actually idles at 1500 for a second or 3 when you throw it in neutral but then it goes back down to 700 or so... I have no idea why but when it was moving a lot I had a vacuum hose disconnected, so check that out if it's bouncing up and down

HondacivDX

you mite have messed with the ilde adjustment on the throttle body or you could have a tps acting up casuin ur high idle

slk08

Ok so ive rechecked the throttle wire and im pretty sure its adjusted correctly. I dont really know how to explain it that well so i was able to make a video and i also found a video that had a similar problem. I also took a picture of what i did.

In the picture i removed the intake throttle some wires/sensors that connected everything and that was about it? didnt really do much i just cleaned the inside of everything. After that I just put everything back in. A little bit after that i drove around and the weird idle started happening.

https://honda-tech.com/forums/honda-civic-del-sol-1992-2000-1/very-bizarre-idle-issue-help-00-si-b16a2-2688646/ In POST #11 is basically what is happening to me right now. It sometimes occur around 1500rpm or around 1000rpm weird...

After i let the car sit for a little bit and then start it off this happens when i step on the gas. After i give it a little gas it goes up again and then finally comes back down.

http://www.youtube.com/watch?v=hHDrHS5lPO0

I previewed my post wasnt sure how to make them in order but its suppose to go picture first link and then youtube link.

white ej2

Did u take the throttle body off the manifold when u cleaned it?

slk08

yes i did

joelmatt89

you may have damaged the tb gasket or something when you took it off causing a vacuum leak which would cause the jumpy idle you are experiencing

OhMy-EK9

iTrader: (1)

most likely the thortle body gasket is on backwards or torn in a spot where the vacuum lines run through. check n keep us posted.

slk08

hm so do i have to get a new gasket or is there another way to tell if it is or not?

white ej2

You should just replace the gasket, it'll be pretty cheap. In the mean time you might be able to use a little bit of rtv where the gasket is torn, but its questionable if that will work.

oh and if there's nothing wrong with the gasket make sure that both surfaces on either side of the gasket are clean

slk08

ok well im about to change the gasket and look for any vacuum leaks but in the mean time do you think there could be something with the iacv? or something to adjust or something like that?

white ej2

Its definately possible but if you haven't messed with it then I dont think thats the problem in this case

slk08

well i changed the gasket and no luck. i read about some iacv and fitv problems and to test it out if it was iacv they disconnected their iacv and it was suppose to idle lower or something like that. The iacv is the thing thats next to the tps in the picture i showed? and my car doesnt have fitv or does it?

kulo

im having the same problem with my tb
i installed ek9 tb onto my s2 pro series im
with outlaw engineering gasket kit
it only does it when its cold doe
when the motor is hot
its fine

could be air in the system?

slk08

hm im not really sure then =/ I didnt tamper with anything else. Does anyone know what else it could be?

baromeo

Cooling system has nothing to do with your problem. Hi idle is a indication of a vacuum leak. Rising and dropping idle is caused by a malfunction in the iac circuit. If u have a aftermarket cold air or short ram intake check the vacuum hoses near the throttle body n make sure they're all n the right ports.

slk08

im pretty sure theirs no vacuum leaks because i also doubled checked those when i replaced the gasket so it could be an issue with the iac? I dont think it could have gone bad because it was fine before i cleaned it out the throttle body but how would i test if it was the iac?

Former User

Are you able to kill the idling engine by covering the top of the throttle body with your hand? If not, you definitely have an intake air/vacuum leak.

baromeo

well if it was a iac it will set a dtc. so if ur check engine light is on, check the code, a iac will be a p0121 or soemthin around that. if no check engine light is on its gonna b vacuum oreinted.

dale m.

mine did the same thing i cleaned the iacv and it hasnt done it since

Thmanx

My car does this as well, has a fluctuating idle. Only way for me to fix it was to adjust the idle screw (which is now as closed as it can get) and even now it idles a little funny.

I've checked all my hoses and connections with break cleaner, no sign of leaks. but unplugging my IAC drops my idle down to normal, my IAC is just strangely over active.

just for kicks, try unplugging your 2P IACV connector on the back of the manifold, and see if the problem continues

(stock B16A2 idle when you disconnect the IACV should be at about 450 +/- 50)
Normal Idle is 750 +/- 50


try that, and see if your 'confused' idle goes away.