Idle Adjustments

[gkcopperdrag]

Found the ICS Valve... how to adjust the idle? I found a hose coming out of the bottom and it leads to a little connection with an adjustment screw in it. Is this where I adjust? I'd rather ask first instead of risking messing up the engine. =)

Thanks,
GK

[Enlightenment]

Same question here

[Diff Operator]

What does it actually look like I looked because my car was idleing a little low and couldn't find it. Descriptions?

[JekylandHyde]

On the turbo MR2, you do not adjust idle at the valve (which is under the TB).
You adjust it at the screw on top of the TB. I suspect the NA is similar.

[gkcopperdrag]

yup that was it, and my idle is as low as it can go ( still at 1.4k ) =/

Dane, its a white flathead screw on the top of the throttle body part closest to the rear of the car.

[MitchB]

Unplug the three-wire connector to the ISC coil. If the idle drops a lot, your ECU or wiring from the ECU is likely bad.

If nothing happens to the idle, your ISC valve is likely stuck from gunk being washed into the tiny bearings. This happens from mileage, or when someone uses brake or throttle cleaner on a Toyota (and should know better than to do so).

[MR2Jedi]

Originally Posted by JekylandHyde

On the turbo MR2, you do not adjust idle at the valve (which is under the TB).
You adjust it at the screw on top of the TB. I suspect the NA is similar.

I just looked at my TB and I don't see a screw on top of it? I'm not having any idle problems, was just curious .. am I missing something?

[MitchB]

The rubber cover plug might actually still there.

[MR2Jedi]

I see 2 places that might have a screw under them. one is labled "e" the other labled "p"...is that it? and there are vacuum lines that come from them..

[MitchB]

No, those are plugs from manufacturing the bores for the hose tubes.

In your pic, look just to the right of the P-port tubes at the "tubular" shape in the throttle body. It looks almost like a bolt location, and it's right next to the mounting bolt. I seem to remember that's where the adjustment screw is.

BTW, you are supposed to short the TE1 and E1 pins on the diagnostic connector before when you adjust the idle, then go for "numerous" starts and stops with a warm engine.

[MR2Jedi]

OK, I'll take a look.. thanks for the info..

[Enlightenment]

I've turn the screw all the way down, but it's still high (still staying at 2k)... What can be causing this?

[MitchB]

1. Too much tension on the throttle cable, it needs adjusting.

2. An ISC that is flat out stuck open.

3. A worn throttle body.

4. A failed vacuum throttle opener, if the Turbo has one. (A round vacuum-controlled piston that opens the throttle at low vacuum, and lets it close fully at idle.)

Try pushing on the throttle cable drum and see if you can close the throttle more than it is while idling.

[jtl]

if its an N/A you're talking about, then the high idle is most likely due to the ISC sticking. There is a little valve contained in the ISC body which actuates electrically to port fluid (coolant) thru it (don't ask me exactly the purpose of the coolant - I guess when the coolant warms to a certain temp, the valve close/opens to reduce the idle). I tried cleaning the valve and it didn't help much. Got one of a celica engine - same engine - and it did a little better job (idle went from 1600 to about 1200 rpm).

I also thought I read somewhere that someone tried to adjust the spring tension screw to compensate - yes there is a spring inside the body as well - and had some luck. I haven't tried that before but am thinking about it.

[MitchB]

The coolant doesn't go through the valve, but instead is there to, 1- heat the TB to prevent icing, and 2- to do cold weather (very cold) idle compensation.

You can clean all you want, but if you don't totally disassemble the ISC so that you can clean out the TINY ball bearings and oil them, you are just beating yourself up.

Also, a 3SGTE has an ISC almost identical to the 5SFE version, except that the water pipes come in at an angle vs. straight vertical.