KODE

ok....i have a 1990 4runner with a 22re. i am having high idle issues where the idle will stay at about 1800 rpm after it runs for about 5 minutes. at a cold start, the idle is normal. i recently did a head job, and timing chain job on it, and while everything was apart, i decided to block off my heater tubes with the LC Engineering block off plates.

now heres the thing, does the IACV need to have coolant flowing to it to operate properly? by me eliminating the heater tubes, the coolant doesnt flow to the IACV anymore. also, could it be a bad IACV? i tried to test it by taking off the intake tube, then i put a piece of duct tape over the large hole inside the throttle body and then reassembled the intake tube. when i started it up, it ran alot smoother and no high idle issues at all, even after 20 minutes.

i just dont want to buy a new IACV if i dont have to. and if the heater tubes affect the IACV, maybe ill just put it back on. or can i plug it up? i searched this site and found many mixed reviews on the IACV. i mostly want to know if the coolant will make the IACV inoperable....whats your guys input on this?

Ritzy4Runner

iTrader: (1)

Not why you chose to block off the heater tubes but instead of blocking the ends of the hoses with this plate, just loop the inlet hose to the heater back around to the outlet? I had to do that when my heater core went bad in my old 64 Chevelle years ago as I could not get a replacement heater core.

Not totally sure on the 22RE but the IAVC valve does have coolant running through it. thats what makes the valve work. these are supposed to be a "wax" valve, so as the coolant heats up it "melts" the wax allowing the valve spring to operate and close down during warm engine operations. I'd give the hose loop a try and see how it works out for you.

If the valve was working before you blocked off the hoses, I would reconnect the hoses and check for proper ops. If and when operation changes right after you changed something else, back track to the last know correct operating configuration. Basic trouble shooting is always based on single point failure. The odds of having a different component fail at the same time you changed something else are really high! Reverse what you did to confirm and then trouble shoot the now known issue.

tumor21

KODE, the IACV does need to have coolant flowing through to work. I'm actually going to have to replace mine when I have the time because mine stopped working, luckily I found one off a parts truck that's in good order for $40 bucks. The last time I checked they are like $200 new. I agree with Ritzy, reconnect the hoses and re-test.

KODE

Thanks for the responses guys. well, the reason why i eliminated the heater tubes is because where i live, the coldest temp. in the winter time is an average of 65 degrees. also, there was a pinhole leak in one of the heater tubes in which i would see a small puddle of coolant if i had the 4runner sitting in my garage for a couple of days without starting it or moving it.

ive heard of people plugging the IACV/AAV without any problems. does anyone else have experiences with plugging it? like i said, where i live doesnt get very cold so the high idle isnt really necessary for it to warm up. i usually let it warm up at idle for about 5 minutes before i drive it anyway.

Ritzy4Runner

iTrader: (1)

If you really want your truck to run as it is supposed to don't try to re-engineer how the the thottle body works. If your heater hose has a leak in it, replace the hose. You can bypass the heater with the new hose like I mentioned before just loop it back around from the inlet to the outlet hose fittings, the ones that supply the heater from the engine. This way you don't block off any coolant flow path except to the heater! Running with a bad heater hose is asking for an overheated engine. If its the heater core that is leaking smae thing replace the heater hose and just loop it around from the inlet to the outlet. This way you bypass the heater but still have normal flow for the Throttle body so the idle air control valve works as it is supposed to. Good luck

KODE

ok... since i blocked off every one of my heater tubes on the block, theres no way i would tear apart the top half of the motor again to reinstall new ones. i decided to just plug the IACV/AAV with steel grade epoxy. i read how to do this on another site.

i took off the TB and IACV on my 22re, then filled the port where the air goes in through the small hole on the bottom of the TB. i then reinstalled it after it hardened and tested it out...... it now runs like a champ. i still let it warm to operating temperature, and there is no sign of the high idle and idle surge. Thanks for all the input guys! i appreciate the help. maybe ill do a writeup on this because i noticed alot of people on here has come across the same problem.

keithdphan

[QUOTE=KODE;51481221
now heres the thing, does the IACV need to have coolant flowing to it to operate properly?[/QUOTE]

iacv requires the coolant to heat up wax-like valve to bypass addition air by the throttle body. without cooant valve is wide open, or is completely close. whichever one it will alter your idle speed, that is when your not on the throttle. for me it made my idle surge up and down but driving/acceleration was normal.

KODE

since ive blocked it off, the idle has been perfect. no problems starting. my cold start is about 80-85 degrees every morning in the summer and around 70-78 in the winter.

Flash319

Coolent is need to shut the valve. It works off heat from the coolent and nothing else. You can't bypass it or you will never have a proper idle. The valve is leaking air into the engine past the butterfly. When the coolent heats up the "wax" it closes causing the idle to drop. This is why you must "burp" the system or you will have the hunting idle.