So my engine seems to be idling normal (sounds right, doesn't surge, idles smooth, etc.), but it's just a little high. I know idle is suppose to be like 650RPM. I'm not sure if there's anything really wrong or not, it just seemed odd that it idles at nearly 1k RPMs. I don't know when it started doing this, just kinda noticed it one day. I have done quite a bit of maintenance (see 2nd half of 2nd post in my project thread for a list) and the car is pretty much in tip top shape, so I really don't understand what's up with this. There are no vacuum leaks, or any leaks of any kind for that matter.

Related maintenance includes new Fast Idle Valve complete assembly, Coolant Flush and bleeding, cleaned the IACV/new screen filter and o-rings, Ignition Timing is dead on, New timing belt, new timing belt tensioner, new water pump, engine timing is dead on (as in crank and cam are in sync), new spark plugs, new o2 sensor, new spark plug wires, and other things which are all listed in my project thread on the 2nd post.

 

Does it warm up to normal temperature? The engine will idle fast until it is fully warmed up.

With engine fully warmed up, disconnect the IACV wire and adjust the air screw for idle of about 400 rpm (engine should be starting to shake and threaten to stall). If you cannot slow it down, something is letting air in when it shouldn't. Then reconnect the IACV and normal idle should be established. You may need to reset the IACV code after doing this.

 

Yea, it warms up. It does what you are talking about. When it's cold it starts idling at about 1.5k to 2k and then slowly makes its way down like normal as it warms up.

I'll try that. Where's the adjuster screw at?

If the test shows that air isn't getting in somewhere where it shouldn't, do I use that screw to adjust my idle down to 650?

 

Adjuster screw should be on the top of the throttle body. It looks like a round plug with a screw slot in it. Do not adjust the little screw that stops the throttle linkage (but do check that your throttle cable is slack at idle).

Adjust the screw for lower than normal idle with the IACV disconnected. The ECU will then drive the IACV to regulate the idle at 650. Adjusting the screw with the IACV connected may seem to have no effect because the ECU is fighting it.

Also don't trust the dash tach to measure idle rpm accurately. It is not intended to be that precise.

 

I've checked it before I am pretty sure it's the same thing I checked. As long as the butterfly is completely closed during idle and as soon as the gas pedal is moved at all it opens, that would indicate it is adjusted correctly, right?

So it's possible that my idle is just out of adjustment? If so, is this how I go about correcting it? (1. warm up engine, 2. turn off, 3. disconnect IACV, 4. turn on, 5. lower idle to below normal (650), 6. turn off, 7. connect IACV)

If nothing helps, should I perceive this fact to be the problem within itself and there is really nothing wrong?

 

alright i tried it, and i even turned the idle down as far as it would go (like 400), did the procedure by turning the engine off, plugging the IACV back in, and resetting the ECU, and now it idles at 800RPM.

if i try adjusting the idle with the IACV plugged in, it adjusts and the ECU doesn't correct it.

My IACV has been cleaned.

Does this indicate a bad IACV?

 

The IACV may be sticky. Over a range, as you open the screw up, the ECU should counteract and lower it back down.

It's supposed to idle higher with the A/C on. Perhaps your car has some rigged wiring so the ECU thinks the A/C is always on? (even if you don't have A/C, that feature is in all the ECU's).

 

Nope, when I turn the A/C on the idle changes.

 

I think your tach is just off then. The ECU is either going to make it idle right where it should, or it'll be totally out of control.

 

alright. well i've adjusted the idle adjustment screw like you said so now it's different from what it was before... do i just leave it alone now even though i've messed with it?