Matt16

Since I bought my 1990 4Runner with a 22RE, had an occasional loping idle. When I cleaned the throttle body out with TB cleaner, the idle increased further and the loping became more apparent and more frequent. I was pretty certain I didn't have a vacuum leak as I had done a really thorough check after I re-installed the head on after the timing chain/ head gasket repair. After doing a lot of research, here's what I came up with. It is actually a really easy fix.


Here was the fix: My idle was set to the wrong speed and causing the loping idle. It was further increased by cleaning out the gunk in the intake and TB. Here's why the idle speed caused the loping: when the engine computer senses the revs are at about 1800 (don't quote me on the number) and the brakes are on, it figures that you are stopping and decides there is no need to be using any fuel so it cuts the fuel supply to nearly zero. So, when the idle is set too high, the idle climbs to 1800rpm, where the ECU cuts the fuel supply and the idle drops. Then, because the idle is set high, it climbs back up slowly to 1800 rpm, where the fuel suply is cut again and so on. This is why the idle only was jumpy when the brakes were on.

I adjusted the idle by turing the flat head screw on the passenger's side of the throttle body. When the idle was brought down to ~750RPM (judging by the dashboard tach, the problem was solved.

Here's the links that clued me in to this:

http://www.geocities.com/toyotashawn/bizzareidle.html

http://www.4crawler.com/4x4/TLCA_Tru...ech.04.09.html

This link gave me some background, but put me onto the wrong track thinking there was perhaps an air bubble in my Auxiliary Air Valve (underneath the throttle body):
http://www.toyotafans.net/22re-high-...cold-t3574.htm

The Haynes Manual also points out that the high idle can cause loping and how to adjust it, but does not state why high idle causes the loping.

Hope this helps those with the annoying loping idle,
Matt

89pickupsr5

good stuff man

rdlsz24

750rpm is the correct idle for the 22RE.

Rob

Targetnut

as simple as it is it seems,

there are a lot of prople that can't get that loping/suging idle thing fixed.

You done good with using your information resources and following through to find the conclusion.

One thing that also seems to elude some folks is that there can be a problem with the auxillary air valve that can increase the idle speed (sometimes intermittently) and also result in the loping/suging idle.

good fix, and good post

Matt16

I cleaned out all the little channels and passage ways in the TB with TB cleaner and a paper clip. Used a lot of shop towel as well. This opened up the passage ways enough to really bring up my idle.

Shoua

I've tried that already, and still mine idles. My throttle body screw, actually, is turned all the way down, to where my truck should be dead. Idle is still the same. Some state I just need a new (or junkyard) throttle body.

Matt16

Correction: I called the Auxiliary Air Valve the Idle Air Control Valve (shame on you Heineken)

Try taking the TPS off, then completely removing the TB. Liberally soak it in TB cleaner. Sounds like the AAV is stuck open. This valve uses coolant pressure to control air flow in a cold engine. As a result, my guess is that there is some crud from the coolant that is sticking the valve open or there is gunk from contaminated air (oil fumes from the PCV, air pollutants etc) sticking the valve open from the other side. Soaking it with TB cleaner might help. But make sure to remove the TPS first!!! Read up on the TPS so you don't screw it up when you remove it.

Here's a picture of the AAV:

CChudalla

I know this is a old post and this might be a stupid question but I just took iff my TB and cleaned it and i IACV really well now does the IACV use pressure or temp to close the valve i'm just makeing sure this is my first toyota and i've only owned her for about a week and a half i am haveing the same problem u were and i have tried everything that i and almost anyone else could think of

Junkers88

It uses coolant (temp).

Skilo47

yeah i have the same problem with my 91 toyota 4x4 pickup.

i took the throttle body off and cleaned it thoroughly with TB cleaner.
i took all the vac hoses off and cleaned them with TB cleaner
took air intake hose off and cleaned it out good.
adjusted idle air bypass screw turning it all the way to the right but that still only calmed the insanely high idle down just a tiny lil bit.

it seems to only start to surge when the engine gets hot and also when the engine is either hot or cold when parked with my foot on the brake.

i have heard a few other things on other forums about a "cold idle intake valve" or "cold idle intake sensor" (forgive me if those terms are inaccurate) but i have not tried any adjustment of that as of yet but i will look into it.

i also have not tampered with the throttle position sensor but that is also something i might look into.

if i can't get this fixed then i will be forced to sell this truck even though i like it alot but i just can't drive this thing like this much longer.

edit*

just another thing i want to add. i posted in this forum on a different thread a few months ago and might have said i fixed it but i guess i was wrong lol. i did change the thermostat and for some odd reason that magically stopped the surging idle but a few months have now passed and here i am with the exact same problem i had before so i guess it turned out to be just a temporary fix. =(

Matt16

So basically, the fix I used as indicated above was to clean all the gunk out of the intake with "intake cleaner" (NOT carb cleaner) and then set the idle speed once the engine was up to operating temperature.

I still have to reset it once in a while as it climbs or drops on its out over the period of a couple months. I keep a screw driver in my arm rest and adjust it every couple months when i notice its idling high or low.

Skilo47

well i cleaned the same parts you cleaned but that dosent seem to be working for me . alot of gunk did come out but apparently that gunk really wasent effecting the idle.

im guessing it has something to do with the cold idle sensor thing.

i had an older toyota celica once with a 22r engine and to this day there is no problems with it. want to know why?........it isint fuel injected! .

i think designing a car to where the computer has control over almost every aspect of the engine is just a money racket scheme these car companys use to get richer.

Matt16

Until you try to climb a steep hill and stall because all the gas drains out of your float bowl. I used to think the same- that all the computers were junk etc, but to be honest, fuel injection is probably the biggest, most significant advance since I dunno...the overhead cam or something or maybe even bigger

Skilo47

that's my problem you see. i can't set the idle.

the idle is literally jumping all over the place you can turn the screw all the way to the left or right or take the whole darn idle air bypass screw out of the throttle body if you want and it does no good.

i do have some good news though. i believe i have located the cold idle cylinder sensor on the bottom part of the throttle body .

i disconnected both of those sensors and the idle did calm down but started surging again when i put my foot on the brake.

really if i had the money i would just buy a old 22r engine and swap it out.

from my experience the 22re isin't as durable as the 22r .

qdude79

I'm going to try plugging the hole to the IAC from inside the throttle body bore temporarily to isolate that as the problem (hopefully). It's a start...

Skilo47

that might not be a bad idea just so long as you use something to plug it that wont come out and get sucked into your fuel system.

here is a picture of that cold idle sensor just in case anyone is curious as to what it looks like.



or in case it dosent display http://img39.imagefra.me/img/img39/2...rm_543b26d.jpg

toyota4x4907

Have you tried disconnecting the brake booster vacuum line and plugging it with your finger to see if the BB is bad?

qdude79

toyota4x4907, if you're asking me, no, I haven't. Not a bad idea, though. No brake problems, so I never really thought to check.

toyota4x4907

uhm. i guess I was talking to both you actually. I didnt realize you had a problem too. I guess I should pay attention more...

qdude79

Would it work the same if I just pinched the line with some pliers?