peterls

So, ever since I bought my used 1990 LS400, I kept thinking that very high RPMs were normal on my car when I first start it in the morning, especially since everyone is complaining about that same issue.

However, since I cleaned my IACV, when I start the car early in the morning, even when it is very cold outside, the RPMs are only a little higher, but not terribly high. They used to be probably in the neighborhood of 3000rpm (don't know exactly since my cluster is not working), now they are more like 1500 rpm at the most. So, big improvement there too. The car used to shake a lot also when it was cold, and although that has a lot to do with engine mounts, now the engine is much quieter and relaxed even when cold.

Next thing I want to see is if I am having any more improvement with MPG - at least I am spending less gas every time I start the car cold.

BluesImage

Ok I have the valve off, how do you get it apart to clean?

peterls

If memory serves me, there should be four small phillips screws on the back, just unscrew them and it will all come off. The middle plunger/valve thing is a screw type so you may have to turn it a few times to come out... and then dip it in b12 chemtool it should clean it up no problem.
Then clean the interior of the housing, there should be some weird looking patterns on sides - those are some type of electromagnets, so they should be perfectly clean (but don't strip the metallic looking finish on that!!!), and watch for the little round flex plate on the bottom, it can easily fall out and get lost...
hope that helps. There is also a write up somewhere, I think on planet soarer or some place like that. Just do a search on google.

peterls

here, found the writeup on planet soarer (same engine)

http://planetsoarer.com/IAC/iac.htm