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High Idle

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Old 05-12-11, 08:27 PM   #1
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Unhappy High Idle

Well,

A little back ground. The car was idling fine before I sprayed water into the condensor which in turn got into the spark plug areas. I took it home (it was missing pretty bad) and took the top off of it and blew everything out, cleaned the plugs, and changed the wires while I was in there.

Put everything back together, and I'm getting a high idle (1500 RPM cold or hot). I saw the hose couplers had cracks around the reams, so I taped them up (just to verify) and shot carb cleaner at them (no difference).

I then put new clamps on it because I knew it was old. No change, still high idle.

I sprayed and visually checked every single freaking hose in the bay, no change.

I removed the IAC and cleaned it earlier today thinking thats what it was but after it being a little dirty it still was fine in terms of movement and looks.

This where I gets tricky, it dropped down to 900 RPM for a few minutes, drove it around the block and came back - turned it off and then back on- 1500 RPM. I was ready to throw my wrench at the car at this point...

I did reset the ECU via Dome & EFI fuse each time, but I took it a step further and unplugged the battery on both sides.

I have a Lexus technician swapping the mounts out on Saturday for me and he said he would look at it but I can't help but want to fix it before hand.

I did notice that the screw on the left hand side of the throttle body (looks like a set screw) is broken off at the top [like the previous owner was messing with it trying to get the idle up and didn't realize it locked on the other side]. Can someone shoot me a picture of this to see how many threads are showing? I know it's a hard angle but mine has about half an inch showing and it seems wrong.

I'm wondering if after fixing the IAC and all the vacuum leaks from the intake tubing that NOW that car can idle at the right speed and NOT need to be adjusted (hypothetically speaking).

I unplugged the IAC, and reset the car and the idle shot up to 3000 RPM so I think it's doing something.

I did notice the coolant temp sensors were soaked (but still reading out on dash, not sure on ECU). I cleaned them up and no change.

It does smell like the car is running rich. Pretty much the entire tune up has been done at this time.

Someone throw ideas at me here.
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Old 05-13-11, 07:58 AM   #2
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Update.

No codes at all.

Pulled the coolant temp for ecu connector and no change. It has to be the freaking IASC
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Old 05-13-11, 11:12 AM   #3
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Checked the adjustment screw that was adjusted before and went ahead and ordered a new throttle body gasket even though the old one looked ok.

Still the same 1500 RPM idle.
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Old 05-13-11, 12:04 PM   #4
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Anyone? *Crickets*
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Old 05-13-11, 01:43 PM   #5
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Check all of your vacuum lines. High pressure water may have taken one off.
Just a suggestion.
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Old 05-13-11, 01:44 PM   #6
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I've marked every single vacuum line on a diagram and under the hood to check them. I've also taken off every single line at both ends just to make sure there wasn't a change.

For it to idle from 800 RPM up to 1500 RPM seems like it would have to be a pretty significant leak (i.e. Brake Booster, etc).
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Old 05-13-11, 02:00 PM   #7
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agreed...
Seems that this is an ongoing issue, usually associated with cleaning anything in the intake... this, however, is not your issue.
If you have already reset the ECU, and can't find a possible leak in vacuum, ride it out over the next couple of tanks of fuel and see if the ECU relearns the propper conditions.
If, after 500 miles or so, you don't see improvement in the condition, definitely have it looked at by toyota or lexus techs.
Anyone else have any ideas?
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Old 05-13-11, 02:07 PM   #8
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Quote:
Originally Posted by tjcetanyan View Post
agreed...
Seems that this is an ongoing issue, usually associated with cleaning anything in the intake... this, however, is not your issue.
If you have already reset the ECU, and can't find a possible leak in vacuum, ride it out over the next couple of tanks of fuel and see if the ECU relearns the propper conditions.
If, after 500 miles or so, you don't see improvement in the condition, definitely have it looked at by toyota or lexus techs.
Anyone else have any ideas?
I cleaned the throttle body out - that's why I assumed maybe the IASC got some gunk in it (which I took apart, it had no issues).

I reset the ECU every time I made even a minor change.

It was idling fine before the ignition messed up at the car wash - then fixed the ignition and had a high idle.

I've checked so far...

1) Timing
2) TPS Specs
3) MAFS
4) IAC
5) Couplers
6) Vacuum Hoses
7) Gasket [TB Gasket didn't look bad)
8) Brake Booster
9) Coolant Sensor (ECU)
10) Grounds

I cleaned the spark plug galley out but I don't think there are any vacuum lines below it in the actual area next to the plugs.

I checked all of the vacuum hoses on the back side of the motor, below the LIM, above the UIM, on the sides. I even went as far down to the charcoal canister.

The car runs and accelerates like a dream it just idles high.
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Old 05-13-11, 02:14 PM   #9
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Try to wait it out then, hope the ECU relearns the proper A/F over some driving time. 500 miles is "rule of thumb".
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Old 05-13-11, 02:14 PM   #10
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good luck. Any updates, keep us posted.
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Old 05-13-11, 02:23 PM   #11
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Is there a factory coating on the TB butterfly that keeps it sealed? I'm taking the hose off tonight.

I'm in my car eight hours a day, 500 miles has been reached already
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Old 05-13-11, 02:36 PM   #12
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I don't recall anything... it has been quite a while since I have been in it. I can check tonight though. I've got the head off and apart on the '95. Easy to get to. LOL
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Old 05-13-11, 02:54 PM   #13
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Raggggeeeeeeeeeeee.

Alternator checked out perfect.

Going to buy vacuum hoses and just start replacing them.
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Old 05-13-11, 06:06 PM   #14
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After looking closely at the TB butterfly, other than the TPS sensor, that you already checked, not much going on there.
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Old 05-13-11, 07:07 PM   #15
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I'm just going to get another Idle valve even though current one is spec.
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