How do you adjust the idle on a Civic 91 Si? dont see amechanical adjuster, looks to be a vacuum operated selonoid? My car has started to drop idle down to 250-500 RPM when coming to a stop. Also the battery light will come on (like it stalled) but tghe car is still running??? Light goes off after 1-2 seconds. Ideas?

 

First warm the car up to operating temperature. Disconnect the IACV, the solenoid on the back of the throttle body. Then using the idle adjustment screw to achive 700-750 PRM. The adjustment screw is on the top back of the throllte body opening. Looking from the passneger side of the car look at the top left of the rubber intake boot. It may be filled with wax if the idle has never been touched from the factory. Turning the screw in will reduce the idle RPM backing it out increases the RPM

 

Just disconnect the vacuum line from the solenoid on the front of the t-body? How do you remove the wax, if its still there? I must have overlooked that somehow.

 

Don't remove any vacuum lines. Just unplug the electrical connector on the IACV. The adjustment screw on the front of the throttle body is covered in a type of wax. Carefully scrape it away to reveal the slotted head screw under it.

I believe the base idle should be about 650rpm. Once that is set, plugging in the IACV should raise it to the 700-750rpm range. If the engine stalls when you unplug the IACV, back out the adjuster screw a 1/2 turn at a time until it stays running. But...read the following suggestions.

You may want to remove the IACV and clean it first. Two 10mm head bolts hold it to the throtle body. You should be able to move it away from the throttle body enough to clean it with carb cleaner spray without removing the coolant lines going to it. Don't loose that figure 8 shaped O-ring. There is a fine mesh screen covering an air passage and I bet yours looks like a solid rubber disk.

BTW, your other post deals with excessive oil consumption. Clean out the PCV system and replace the PCV valve.

 

Thanks alot! From the pass side, the IAC is on the left w/an elecrical plug coming out of it?

Where is the PCV valve located? I looked at all of the vacuum lines comin out of the intake, but couldnt trace any back to anything that looked like a PCV valve?

 

bump.

 

Just wanted to say thanks, the PCV was complete clogged. Hopefully this helps. Although looking at the t-body I still dont see the screw, etc like you described.

 

I need to adjust my idle;


i shall try what i've read here

god i love this place