stanleybg

I did this two times.I even get the all throttle apart changed all seals with OEM. Fully cleaned IAC valve like new.But sometimes the car still when hot in Drive rpm drops below 500.
MAF also cleaned inside with brake cleaner , but no success.
Throttle had carbons inside like the pictures in the forum ,i have cleaned it very good until shine.It rotates very very easy.
All throttle gaseks are new OEM.All intake gaskets i have changed with new OEM.
Do you think that if i replace all that IAC part of throttle body will help ?
Thank you

salimshah

ECU sends signal to the IAC coil. The sensors sending signal to the ECU, ECU, IAC coil wires connectors .. what else.

And cleaning does not always solve the problem. If you go to the dealer they toss the old IACV out and put in a new one.

Salim

murphysf

Anyone have the part number for the oring?

I just did this after work. I didn't even attempt to loosen the screws with a screwdriver. I took a stubby screwdriver and a hammer and tapped on both of them several times. Then I took a small pair of vise grips and grabbed the edges and broke them free. Took a good amount of torque and then heard them crack loose. I then used the screwdriver to back them out.

After I pulled the "motor" off, I felt a little bit of "grit" when turning the shaft back and forth. I sprayed carb cleaner and kept twisting back and forth and now it is smooth, I did remove the lower hose but while spraying kept my finger on the port so the carb cleaner would stay in there and not just run out.

Anyway, my oring is a bit distorted and out of shape. I can't seem to get it to stay in place on the valve. Is it supposed to be in the recessed groove around the shaft? If so it seems like my oring is a bit too big? Perhaps I shoudl buy a new one.

For now I am leaving the car apart for the evening to see what I hear back about how the oring seats? And if anyone has a part number that would be a great help, I can see if the local toyota or lexus dealer has it in stock, tomorrow (sat morning)..

Thanks!!

murphysf

so I just sprayed some silicone spray on the oring on a paper towel and let it sit for a few minutes. The oring seems to have retaken its form without any distortion. I was able to get it to sit on the valve and reassembled it.

My idle is now a bit on the higher side, should I disconnect the battery for the ECU to re learn / program itself?

I thought it would be worth mentioning my symptoms that lead me to clean the IACV. A couple of years ago I started the vehicle cold in the morning and backed it out of the driveway and then shut it off. The engine was only on for less then a minute. About two hours later I went to start it and it would start and then die immediately. If I kept my foot on the gas pedal a good bit it would run but once releasing the gas pedal it would die. What I would do is keep it reving and then quickly take my foot of the gas and shift it into drive and then keep my foot into it and drive around. I would need to find a route that had no stop signs so I could keep my foot into it and drive it. After a few minutes I would take my foot off the gas and the idle would be fine, no stalling. This has happened about 10 or so times in the last two years. I noticed it had to do with the car not running long enough or warming up after a cold start. I knew about this post but felt like I had a work around and was always able to overcome the stalling. This week it started happening a couple of times on the first start in the morning. Therefore I went ahead with this procedure this evening.

So back to my original question, should I disconnect the battery and let the ECU reprogram?

salimshah

As long as it is not stalling outing idle rpm stays below 1K, you can let it learn on its own. It will not take days.

Salim

murphysf

so is learning an ongoing thing that doesn't take any action by a person (for example disconnecting and reconnecting the batter)?

If anything the idle seems a bit on the high side just slightly under 1k rpm, however I just drove it for about minutes after I cleaned the IACV. Perhaps I will see what the idle is after driving it a bit longer.

salimshah

Driving will not make it better. Let it idle a bit. If you pull the battery terminal, the ecu still needs to learn ... you just are starting from the midpoint vs where the last learning was. As your idle time stretches, the idle rpm will tend down.

Salim

murphysf

just to confirm I should or should not pull the battery terminal?

salimshah

If the vehicle is not stalling and not idling over 1k, just let it be. Let it sit and idle for about 10 minutes.
You would not do any harm in disconnecting, other than loose your settings, but even then the vehicle would learn and get to its proper idle.

Salim

steelgtr

I just paid my very competent mechanic to clean the valve and we still have the cold idle problem. Do these valves fail totally? Anything else?

thx

bob

salimshah

Yes there are times when the whole thing needs to be replaced.

Salim

mrdpboone

carguy07

Assuming you mean the metal elbow?? Maybe try to flush it out with throttle body cleaner or a light shot of compressed air from the throttle body with the IACV open. Thin wire with a hook on on the end to grab the head of the qtip?

mrdpboone

Mrv8q

Glad this thread is still around. I did the IACV clean today; hat tip to the poster who recommended pulling the bottom hose to capture the carbony crud while exercising the valve.

I also replaced the two throttle body air hoses, as the ones I replaced 11(!) years ago were rock hard. I used Amazon hoses which turned out fine. The car started right up, thanks to the posters here for followups.