'97 SR5 Idling to fast!

[Grezdlitn]

Just started working on my first T4R. First order of business was to refurbish the front sway bar as both links were broken and the bushing were torn and squeezing out of the brackets. An hour of labor, really dirty and greasy hands and a few parts....done!
That bring me to my real problem. I cleaned the MAF (searched the forum for methods) and put in new NGK dual electrode sparkplugs. IT starts a runs smooth but the she idles at 1650 rpm. I can cycle the a/c and get it to move down to 1450 but no lower. I let it come to operating temp and still nothing.

I disconnected the bat to reset the computer but this didn't help. Sprayed carb cleaner looking for a vac leak but nothing shows up! Got any ideas?

 

[J-money$$$]

try manually closing the valve on the Throttle body. My was warped and caused exactly what you mention. I could get it to idle right if i manually revved up the motor and slammed it shut and held pressure on it

 

[TheDurk]

Check each of the vac connections by hand. If you changed the plugs, you certainly undid some stuff, so I would focus there first. I had a high idle after a plug change that drove me crazy for weeks. The vac hose to the accelerator opener thingy was SITTING on the nozzle, but it wasn't PUSHED on. I only realized it when I pulled on the hose to see what happened with it disconnected. Voilá! Instant zero cost fix. Don't assume you put it all back--check.

By the way, I could do the same thing J-Money describes. Don't think that automatically means a bent butterfly. If the opener thingy is not receiving vacuum, you can close it fully by adding pressure with your hand.

 

[YotaZach85]

What did you use to clean the MAF?

 

[trailmix]

I had the same problem after cleaning my throttle body a few weeks ago. Turns out i gunked up the IAC valve when i sprayed it out causing it to stick. Its the lower part with the plug on it on the throttle body. I pulled it all apart and cleaned it with a bunch of q tips and carb spray and my idle is back to normal. Might be something to check just in case cause it fixed my high idle issue.

 

[THEREALTOR1]

I think when mine did that after cleaning the throttle body and MAF I just pulled the EFI fuse for about 10 min while I worked the butterfly manually for a minute or two and then when I started it back up I took it for a drive and by the end of the drive it was idling fine.

 

[Grezdlitn]

Quick update. Started her up and manually operated the throttle. Couldn't detect any real difference. Thought I might have disloged some gunk that was holding it open but no change. I let it run and then drove it for twenty minutes. The idle setteled at 1000 rpm with a/c and 1250 without.

I cleaned the MAF with a designated maf cleaner (don't remember the brand) that I picked up at Autozone. I've gone over the vac lines and the condition of some are a little suspect (loose fitting and Hard from age).

I'm really interested in IAF valve (?). The cap with filter came off while I was pulling the intake boot off and I may have gotten trash in it. I'm not sure what this is or does, can someone elaborate?

 

[SRSRunner]

I wanna say its underneath at the base of the t.b but dont quote me on that- I found a diagram awhile ago when i cleaned everything but cant seem to find it now. Also what about the positioning sensor? That can cause idle problems also

 

[YotaZach85]

It's a lot easier to pull the throttle body off the intake to get to the IAC (actually I think you have to) becuase it's on the bottom of the TB. It has coolant lines, an electrical connection, it's directly below where the intake pipe goes in, I think it's 4 phillips head screws holding it to the TB and there 2 phillips head screws holding the motor to the valve....DON'T PULL THE TPS! (throttle position sensor) it's adjustable and can be a pain in the ass to get adjusted properly again. Pull IAC off of the TB and clean it out real good so that you can turn the valve without any resistance. Make sure you get the throttle cable adjusted properly, too.

This is the best I can do for a pic, in the first pic you can see the IAC right under the intake opening. 3.4 Toyota 4Runner Throttle Body COMPLETE, $AVE | eBay

 

[Grezdlitn]

It's a lot easier to pull the throttle body off the intake to get to the IAC (actually I think you have to) becuase it's on the bottom of the TB. It has coolant lines, an electrical connection, it's directly below where the intake pipe goes in, I think it's 4 phillips head screws holding it to the TB and there 2 phillips head screws holding the motor to the valve....DON'T PULL THE TPS! (throttle position sensor) it's adjustable and can be a pain in the ass to get adjusted properly again. Pull IAC off of the TB and clean it out real good so that you can turn the valve without any resistance. Make sure you get the throttle cable adjusted properly, too.

Thanks for the detailed info. Your description and advice is spot on!

I pulled the throttle body this morning and cleaned it very carefully. Pretty carboned up. I removed the IAC valve cleaned and performed the battery supplied power test. The valve moves freely open or closed, however it does not close 100%. I'm not sure if this is right or not. Remaing slightly open might be a intentional metered air flow. I'm unable to find anything definitive about the closed position. Anyone know? There about $150 at the parts house. Kinda pricey just to see if it is supossed to fully close!

I replaced a bunch of vac lines that were suspect and installed a new PVC valve and grommet. Took it for a drive and the idle still remains at 1150 to 1250. I didn't mess with the throttle position sensor as my experience says they are either a go or no go item.

Other than that for a motor with 258,000 miles it runs as smooth as new! I'm ready to move on to something more interesting in my refurbish. Anybody got any ideas?

 

[Grezdlitn]

Fast idle resolved!

I want to say thanks to everyone who responded. I'm liking this 4runner more everytime I get in it!
Decided to try for my state inspection. Plugged my laptop in the obd to see if enough systems were ready to pass. Drove it long enough to bring everything online and the idle settled to 850 rpm. Guess the ecu was trying to figure out what I was up to with all the cleaning, plug changing, disconnecting etc.

On to my next project......timing belt and all the stuff that goes with it!

 

[YotaZach85]

I want to say thanks to everyone who responded. I'm liking this 4runner more everytime I get in it!
Decided to try for my state inspection. Plugged my laptop in the obd to see if enough systems were ready to pass. Drove it long enough to bring everything online and the idle settled to 850 rpm. Guess the ecu was trying to figure out what I was up to with all the cleaning, plug changing, disconnecting etc.

On to my next project......timing belt and all the stuff that goes with it!

:bigok: Glad to hear!