I'm just wondering how i set the base idle. I have a 99 civic hatchback dx 1.6l sohc non vtec it idle's really high but only when it's cold so i want to reset the idle properly in hopes it'll fix the problem. i've checked for vacuum leaks like 5 times can't find anything i've even traced all the lines as much as possible so i think it's just the curb idle so any help would be great thx. i've also searched for an existing thread but didn't come up with anythig for the 1.6L shoc Vtec

 

u sure it's not just warming up? Start it, let it idle high, and see if it goes down after 15 min, if not, then yeah, it's idling high

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Project_99Hatchback &raquo;</TD></TR><TR><TD CLASS="quote">I'm just wondering how i set the base idle. I have a 99 civic hatchback dx 1.6l sohc non vtec it idle's really high but only when it's cold so i want to reset the idle properly in hopes it'll fix the problem. i've checked for vacuum leaks like 5 times can't find anything i've even traced all the lines as much as possible so i think it's just the curb idle so any help would be great thx. i've also searched for an existing thread but didn't come up with anythig for the 1.6L shoc Vtec </TD></TR></TABLE>

it's winter.. it's cold were in canada, our idle's are always high first thing.....

 

ok well obviously it's canada and it's cold but when it idles at 1700 and i hit the gas it revs up and then sits at like 2000rpms and then settles down to 1500 rpms after like a min at 2000 rpms. so i'd like to start by settling the curb idle and then go from there i'm not looing for advice but for an answer to my question thanks. Also on the back of the manifold there is a set screw under a rubber cap you can use a flat head screw driver to adjust it. What does this adjust? I took it out and cleaned all the carbon off it and put it back in since then i haven't been getting very good gas mileage i didn't screw it all the way in probly a full turn and a half from the bottom. should i screw it in more?

 

This screw was on the manifold...or the throttle body? Sounds like the idle air adjustment screw you messed with. What happens if you turn it all the way in? Don't unplug the IACV while trying to set the idle on an engine with a 3-wire IACV....it's not liek setting it on a 2-wire IACV.

 

the idle air screw wich you are talking about should not be adjusted........That screw is set to factory spec......

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by skiano &raquo;</TD></TR><TR><TD CLASS="quote">the idle air screw wich you are talking about should not be adjusted........That screw is set to factory spec......</TD></TR></TABLE>

That screw and the throttle plate stop screw which directly effect TPS output, should not usually have to be touched. IF there is a problem with the idle, there is more than likely a problem with some sub-system like the IACV or a tight valve, etc more so than one of those two screws being 'out of adjustment'.

 

nobody gave u advice, we just told you waht it might have been....

It really doesn't sound like your idle, I am pretty sure if the idle is up too high while the car is finished in the "warm up" stage, the ECU kicks it down, which creates a flux in ur RPM's. It sounds like an O2 sensor, or wiring, I would think this because it sounds exactly like the problem I have with my Ford Probe, pretty sure it's the O2 sensor, but I haven't changed the O2 sensor yet because I don't feel like spending 60 dollars if I'm not sure (yeah, I'm cheap like that)

 

The ECU uses a fuel cut on decel strategy to save gas. When the engine has warmed up (ECT say so), engine speed is above 1100rpm and the throttle plate is closed (TPS says so), then the ECU cuts the injectors off.

Where is this screw that you messed with?



#1, right?

As I asked before...what happens when you turn it all the way in?

 

technically from the picture the number would be 5 but maybe i'm just not looking at it the right way yeah that's the one when i turned it all the way closed there is this hissing noise and it went away and the idle got a little lower i think the more i opened it the more i heard this hissing kinda noise. i messed with the screw cause it was way worse before there was like so much dirt and crap all through the cambers and stuff i just cleaned them out with throttle body cleaner and took the screw out and cleaned it. Since we're on the topic which sensor on this diagram is the iacv and which is the thermol valve

and thanks for the diagram that helps a lot, I appreciate your expertise

 

#2 is the IACV and we don't have a thermo valve. If the screw is all the way in and you cover the hole leading to the IACV...what happens to the idle? Don't bother unplugging it because it doesn't close down like a 2-wire IACV....just cover the hole.

 

i'm not sure i'll check tomorrow what am i looking for what should happen and what might happen?

 

What was ever wrong with the car that you decided to mess with that screw? Was the idle hunting around...or just sticking high? Did you check to make sure the throttle cable had slack in it? I'm guessing since you asked what the IACV was, that you haven't cleaned it...or shot throttle body cleaner into that port I asked you to cover?

The thing is, you haven't said your idle is hunting around which means there isn't a vaccum leak. It sounds more like your throttle cable is tight or you messed with the other screw that by the throttle rotor (what the cable attaches to) or your IACV is starting to stick (mine certainly did and required a cleaning, which brought everything back to normal).

 

yeah it wasn't/isn't hunting just staying at high idle all by itself for a long time then when it warmed up before i cleaned the screw it would stumble a bit at idle then i cleaned the screw and the passage and that got rid of the stumble but now it still is idling high. it's probly the iacv, But i'm not sure how to best take it off, and what to clean once i have it off. what should i clean it with and what should i clean? what exactly does the iacv do? and how can i adjust the screw i took out back to factory spec? and what does the screw change? Also i checked the throttle cable tension and it's fine nice and loose and i didn't change it at all so it shouldn't be that?