fountain

yes, i did research before posting. ALL DAY!
94 pickup
22 re with 150,000 original miles

the truck has began to surge at idle pretty bad and ive began to try and track it down

1. checked vacuum lines and found one under the intake runner with a hole. replaced it and nothing changed

2. checked the little tube on the thermostat housing..even found a youtube video. but mine in on the right side of the housing and doesnt unscrew. went ahead and pulled the housing to check t-stat since it also started blowing water out yesterday. all was well and fluid will come out of the little tube with a pump of the radiator hose

3. checked idle screw. tightened it all the way down and the surging stopped. idle was ok in rpm, but i know this isnt right. i cant remember now if i had surging like this with the brakes applied or not, but it may have

4. cleaned the t.b really well and put duct tape over the hole in the bottom of the t.b. (engine already well warm). this stopped the surging but idle was off. i adjusted the idle back up to 750 by adjusting the screw back out. it runs fine now with no surging anywhere

what does this tell me? is it the auxiliary air valve? can this be cleaned? exactly where is it? could it be one of the a/c vacuum things i read about? it has always had a surging idle with the a/c on..it doesnt do that now with the duct tape over the hole.

this has been a pretty frustrating thing to chase down and i hope im getting close to catching it. ive still got to figure why/how its blowing coolant out the radiator cap. the temp gauge reads normal, but coolant is blowing out. i did get some orange silicone out of the radiator yesterday and got a little more mess out today with a water hose flush

could my surge and the blowing water deal be related?

toyota4x4907

Yes, your surging idle is caused by your coolant loss. You might want to look into it...

fountain

its been surging a little while now off and on, but just started losing the coolant...i think. what is making it do it? the aux. air valve? maybe something is clogging it?

Valvoman

It's hard to figure.

Did you recently fill up with gas? At the same station? I mention this because, maybe the gas is bad. Full of water possibly; this happens in the summer a lot.

Hugh_Mann

If you cleaned a lot of junk out of your TB it'll let in more air which will raise your idle. The black buildup actually seals around the throttle plate when it's closed. At least that's what was happening to mine. I even went as far as removing my TB and replacing a wonky (but non-related) TPS trying to track down the issue. As well, when I pressed on the brakes, the idle jumped between 900-1100 rpm rapidly. This is because the ECU cuts fuel to assist in braking when the engine is ≧1100rpm.

fountain

that cant be it. ive been through a few tanks with the same surging. that would cause it to run bad/skip. this is the surging idle that most have and have fought for a while. from reading all day it seems its never the same fix for the problem though.

fountain

its running normal now with the hole at the bottom of the t.b. blocked off. i just now i cant leave it like this

Hugh_Mann

Sounds like you may have an issue with your IAC then. If it's stuck open, it'll be a vacuum leak.

Edit: I guess the proper term is auxiliary air valve, as you said before. You can remove it to clean it, but it's easiest with the TB removed. You could also detach the coolant lines and blow compressed air through the coolant passage to remove any potential blockage.

fountain

any videos on how to clean the iac/aa valve? im going to try this next.

Terrys87

iTrader: (1)

Here is another members way of checking.

A small victory on the 4Runner today. Received the IACV that I traded some parts for.



First order of business, I wire brushed it and used a scotchbrite pad to clean it up a bit. Then I checked the resistance of the coil. The FSM says 39 to 59 Ohms, this replacement one measured around 51.


Then I thought I would check it's operation before installing it, so I threw it into the freezer for a couple of hours. Took it out and saw the air passage was opened up more:


Next I let it warm up and checked that the air passage closed up. The FSM says it should be slightly open at 68 deg. It was a tad warmer than that here today, passage looks slightly open:


Pulled my old one, swapped this one in. Immediately noticed that my truck now has a cold idle, it has NEVER had one before, so I'm thrilled. Took a look at my old one and noticed it was closed all the way, all the time. I believe the little tab that moves the cam is broken. Glad I changed it.

Hugh_Mann

This is what I'm thinking of when I say IACV/AAV. It sits directly under the throttle body. If you do decide to remove it and clean it you might as well buy a new o-ring too.

Edit: Ahh okay, Terrys87's pics are of an early style AAV.

Gamma_Hugo

I had the same issue with my 22re a while back. Same year. I took off the throttle body and detached the IACV. I ran brake cleaner through the small coolant ports. Turned out I had a clog. Banged it out with a hammer. But, the coolant has to run freely and unobstructed. If you run brake cleaner and keeps back flowing, then you need to clear the obstruction. Might be silicone or some other piece of crap. In my case, my old mechanic left blue shop towel in the coolant system.

fountain

ok, so i cleaned the t.b. and the iac..like pictured by hugh mann. one leg was stopped up bad. i got it all cleaned and put back together and it idled fine and drove fine.

i drove it about 10 miles home and it surged again at a stop sign, but now when i pulled into the driveway and stopped. it was idling a little high so i idled it down a tad and still ran good.

i took the idle screw out put some teftlon tape on it. ive been trying to get the idle set right ever since. i set it with the truck warm. i drove it and it seemed to be high after driving some so i set idled it back down and shut it off. about 10 minutes later i crunk it back up and at start up it was pretty low. a tap of the throttle and it jumpped back up.

is this all sound normal? if this doesnt fix me im lost. what next? tps? i dont see how it could be off after running great for 6 years or so. what/how is the best way to set the idle? cold start of warm? i hope after i get it dialed back to perfect it will be better cause i dont know what to try next

92yote4x4

Tps, had same problem with my 3.0

Gamma_Hugo

Did you put a new gasket on the throttle body? Might be your TPS

fountain

Yes. I made out of an oil filter box. Didn't have any basket material and none of the stores around me had any gaskets either.

Will check tps

punks_is_4x4

I was throwing a code for the tps and I put a new one in before my idle was kinda rough because of the dirty throttle body and butterfly valve oh and the dash pot was filthy. so I cleaned all of that and now I have a surging idle only when I give it gas tho. Terrys87 mentioned the tps may need to be set because it has been stored in the ecu. Reset the ecu by disconnecting the battery for a few minutes and then try it again.

punks_is_4x4

I had my battery undone the intire time I was cleaning everything as well so I know my tps needs to be adjusted

Gamma_Hugo

how to adjust TPS and calibrate
http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml