Thanx to those who took the time to writeup how to clean the Idle Air Control Valve. After 125K miles, I decided to take mine apart and clean it. I was having a slight idle problem where the idle would dip down below 500RPMs and then return. So I took it apart and was amazed at what I found.

When you take it apart, inside there's a metal cap with 3 screws holding it on. When I took this off, the inside was totally BLACK and the top of this cap had a point to it. This "point" was due to years of dirty air/combustion gases that built up over time. Eventually the flow of air through this device would create a 'point' to it, which is what happened to mine. After getting rid of all internal black crud, I pieced it back together and re-installed.

Needless to say, the idle is much smoother now, no more hunting for a steady place to idle. The dips no longer go below 500RPMs and the idle is now about 75RPMs higher now due to less restrictions. Also, probably gained 12HP in the meantime. ;-)

 

Glad to hear it.

Not sure about the 12HP part

 

I need to clean mine out or just buy a new one

My RPMs dip below 500, good to here you fixed the problem

 

yay this gives me hope for my idle

 

did you have to replace the gasket?

 

link to writeup? i'd def. like to do this too.

 

The point is by design - it's called a needle valve.

For those looking for a writeup, it's too simple to actually make a writeup for. Find the IACV (it's between the firewall and intake) - it's about 4" x 4" with 4 electrical connectors attached to it. Remove the connectors, and remove the bracket that one of the connectors is attached to. Then remove the 3 bolts holding the valve box to the intake (12mm IIRC), and take it off the car. Disassemble the valve internals using a phillips-head screwdriver, particularly the big needle valve solenoid in the center. Clean it off using a NON-SCRATCHING brush and carb cleaner. (Do not inhale the cleaner fumes or your nose will run for a week.)

Reassemble, and you're done.

Dave

 

So you saying use something like a toothbrush?

 

Something like an old toothbrush.

I just think a wire brush could scratch the faces of the solenoid plunger and cause it to not seal as well.

Dave

 

Amazing how doing something so simple could help so much . Did wonders for my idle as well.

Another good thing is to clean the throttle body while your at it.

 

is there a link to how to do this? i'm having the same problem and I guess I'll give it a try. approximately how long did it take you?

 

If you read the whole thread, you'll find everything you need to know to do the job.

And get yourself a Haynes manual .... lots of good stuff in there too (in general).

 

Here's the link from the FAQ. Just search for IACV

http://forums.maxima.org/showthread.php?t=254238

Took me about 35 minutes from start to finish.

 

Intersting, did you clean the Throttle body while you where there?

If so, how did it look with how many miles on your Max?

 

I did NOT clean the throttle body when I was at it. I did this about 10K miles ago. You could peek inside the intake manifold and see nothing but BLACK soot on the inside. Maybe someday I'll yank this off and try to clean this.

 

removing the upper IM itself isnt hard, its just all the crap thats mounted on it. Make a note of what you take off, get a new gasket BEFORE you take it off (lol i was a nub) and its not a bad project at all. Advice = change your plugs while you do this, not every day you have the IM off......