Another low idle thread...

[PJT]

B18c2. Stock.

Symptoms:

* Low idle (300-400 RPM) after warm up. Warm up idle is normal and car idles normally for a short time before completely warming up.
* Never stalls. Seems happy to live life at 300 RPM.
* Not jumping/hunting. Just sits there steady.

Things I've tried:

* Cleaned the ICAV a couple of times. Was not blocked etc.
* Replaced coolant and (I think) bleed and air-purged it.
* Visually checked the vacuum tubing, seems fine.

I don't wanna go messing with the idle control screws as it was fine for a long time, haven't changed anything significant.

***Any ideas before I just replace all the vacuum tubing? Really need tiny friggin' hands to get to that little black box under the intake :P

[PJT]

So vacuum lines smoked out. Nada. Coolant topped up, burped all good. Swapping o2 out with another tomorrow and will see. Read every thread I could find. Sooo many posts like mine. Zero fvcking solutions. Like they either gave up or didn't bother to post answer..


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[Martin77]

Is the throttle body clean? How about the mass air flow sensor?

[PJT]

Mass air sensor itself is clean. Throttle body next on the list, thanks for reply.


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[PJT]

Throttle body cleaned. Still not big difference. Adj idle screw also not helping. Next step checking Fast idle wax thingy..

[Martin77]

Do you notice a slight increase in rpm when you turn on the air cond?

[PJT]

Air-con has been removed.

Reading through the service manual there's a few troubleshooting guides which mentions blocking the top or bottom port in the TB with your finger. When blocking the bottom port, there is significant suction, but no change in idle. When blocking the op port, the engine almost dies. Hmmmmm. Make's me think I need better trouble shooting skills.

[Martin77]

I'm just trying to figure out if the stepper motor on the iacv is working. Does the rpm increase if the headlight (and other electrical accessories) is turned on?

How many turns did you adjust the idle screw? The screw acts as a mechanical valve.

[Martin77]

One hole on the throttle body connects to the iacv and the other one connects to the fast idle controller (the waxy valve you spoke of before).

When you adjust the screw its a good idea to count the number of turns so that you can return it to the original setting.

[Martin77]

Is your air filter OK?

[PJT]

I only turned it -90 degrees, so from 12 to 9 o'clock.

The light on make the revs drop like its adding load to the engine.

[PJT]

Air filter fine. Had same revs when filter was off today to clean tb.