Adjusting your fast idle

[Sabz5150]

Didn't see any thread that addressed this directly so I will give you the lowdown. I'm sure most of us know how this is done but for others it isn't obvious how this adjustment is made.

On the intake manifold, you will notice the idle air control valve, the thing that gives you surging idle problems when it goes bad. It will have two screws on the top. (Now I would suggest adjusting this with the engine off) Unscrew them, remove the top and there will be a large adjusting screw inside. You'll need a wide screwdriver or a knife to adjust it. It isn't hard to adjust so you dont need something that will take a lot of force.

Anyway, turn it clockwise to lower your fast idle, counterclockwise to raise it. Put the cover back on, screw it back down and test. This also solves some problems with your idle going way way up there.

Hope this helps.

[A20A1]

Thanks, you wouldn't happen to know how to adjust it for a 95 corolla would you. I'm sure I'll figure it out. hehe

[smufguy]

too late for this thread anyway, but had to clear one thing up. I heard that u are not supposed to adjust the valve at all. Due to their age, heat and wear, the rubber valve is kinda stuck on to the walls and once adjusted would tear. causing even more worse surging. I tried it and it did that twice. i think the best bet is to rebuild that shit somehow

[BITESIZE]

sabz, are you talking about the warm up regulator doohickey?

[bobafett]

yeah i gotta do this, my car idles way too high when cold (2000rpm)

thanks for the clear how-two

[BITESIZE]

Mine idles at like 2000 when cold and surges up and down from 1000 to 2000 until my car is warmed up....is this my problem?

[smufguy]

Mine idles at like 2000 when cold and surges up and down from 1000 to 2000 until my car is warmed up....is this my problem?

cold start up is no more than 1500 rpm for efis. if anything higher, then u gotta look into the fast idle valve (88-89) for 86-87 guiys, well u guys got shit load of sensors all around the car to worry about.

butesize, how is ur pcv system? is there lot of blowby?

[BITESIZE]

how do i tell if it's got alot of blowby

[smufguy]

how do i tell if it's got alot of blowby

if ur changing ur pcv valve a lot of times, then its a sign. If u hooked up a clear hose to the pcv system and see oil just running thru, then its an issue. or even if u see oil dripping a lot from the base of the pcv canister (oil condensor). USually its the unusual pressure buildup in the bottom end that will cause this, also i have noticed that increasing the pressure does result in rough idle. But not surging.

Surging usually is when there is a vaccum leak whre the computer is trying to go in a pulse mode kinda where it corrects and cancels every time causing in the up and down rev of the engine. Open up the fast idle valve and see if u hear a hiss. Also, the sealing ring around the top of the fast idle valve might need replacing.

[BITESIZE]

The pcv valve is ok. I think I might have a vaccuum leak somewhere