How to: Cleaning a Throttle body

I think you mean IAC ? Idle Air Control (valve).

 

Oops, yea. Thanks, now I gotta figure out which one it is.

 

Hello Dustin:

On the 2.7l, the IAC valve is bolted onto the throttle body and has an electrical connector. It is hanging directly underneath when the TB is mounted on the engine, it will be attached when you remove the TB.

and mine was bolted onto the TB with 2 phillips head machine screws that were buggers to get off if you need to do that.

 

Thanks, I downloaded a service manual and found it. I cleaned the valve but I'm thinking the switch is bad. I cleaned the tb as per this thread and it didn't change the way the truck runs when cold. Does the iac have anything to do with cold starts though?

 

dustinj, not sure if your "cold starts" reference has anything to do with hard cranking (turning over [and over] without starting/starting after several cranks), but the engine ground may be an issue (was on some 01-04 models anyway). might be something to look at.

 

i'll be doing this when i change my plugs out

questions about the motor ground...is it the one that bolts to the frame right by the oil filter? what was the issue/repair?

 

sub

 

is it necessary to get a new TB gasket when doing this? also is there a better one to put in? were they updated?

i thought i read something about that

 

Anyone ever decide if the TB gasket should be replaced? I am getting ready to tackle this project and just wanted to know.

 

Got some time today and decided to clean the throttle body. I was amazed at how dirty it was. I was not able to get the throttle body completely off the vehicle. There were some hoses on the bottom that just didn't want to come off so I cleaned it while it was on the vehicle.
I was amazed at how much gunk was built up in there. I shined it up and made it look good!

I didn't have much luck with the Deep Creep stuff. It didn't seem to take off anything but good old fashioned carb cleaner worked perfectly.

 

My cel came on after this. Anyone recommend checking anything?

 

Nevermind. I reset the comp and it's good.

 

Do the hoses spill a little bit or a lot of bit? And does any of the stuff that spills need to be replaced?

 

Just in case anyone decides to clean the throttle body while it's still attached and manages to shoot the little red straw from the carb cleaner past the butterfly and down deep into the intake manifold: duct tape a length of 3/8" transmission hose to the hose of a shop vac. You can then turn the vac on and push the tranny hose past the butterfly and down into the intake to suck the straw out.

 

Just removed/cleaned my throttle body today so I thought I would breathe some new life into this old thread. The back of my throttle body (side facing intake manifold) was completely black and the inner diameter (bore) of the the throttle body was sludged up. The cause of all this crud...

I am assuming it has to do with the EGR (exhaust gas recirculation) and the PCV valve. Not sure how much overlap there is between the intake and exhaust valves on the typical Toyota motor but this can cause exhaust gases to push into the intake manifold. During the very end of the exhaust stroke the intake valves will start to open and some exhaust is pushed into the intake (natural EGR effect which has nothing to do with the EGR system). The overlap in valve timing (controlled by the cam lobes) increases the engines pumping efficiency; too much overlap is bad but won't happen with stock cams with correct timing.

Getting the coolant lines off the throttle body was the only thing that gave me any fuss; don't get discouraged though. Try twisting the coolant line where it connects to the throttle body as they like to "freeze" up and twisting will break them free. Mine were fused too tightly so I used a small flat head to pry my way between the coolant line and the fitting. A little lubricant (WD-40, PB blaster, even sea foam) can also help. Good luck out there.

 

I got a bird nest in my deck plate hole and while cleaning it out I must have gotten some junk past the filter. Now my CEL is on. I had the idea to clean the MAF, intake tube and air box, i got a new filter also. It was recommended to me to clean the TB too. This thread seems to be very useful and I will try this one day soon.

I have a K&N filter that I no longer use because it is a pain to keep up with especially with the deck plate open. I can see how dirt gets through easily.

 

i am planning on doing this to my 2010 4.0 soon when i have the time,a couple questions to those that have done it.did the check engine light come on after this was done and did disconnecting the battery cable reset it.
i did this on my yaris and plenty of undiscussed issues popped up for me,i dont want that.
i am planning on doing the iac valve at the same time,i dont see why having it disassembled to that point one wouldnt do it.does anyone have the torque value of the tb bolts and the iac screws????

 

I dc'd my negative terminal before doing anything and never got a CEL. throttle body bolts are torqued to 9ft lbs I believe.

 

I am new to this forums and Can't see your pictures

 

Images no longer loading. Does anyone know where I can find a similar right up? The text is excellent but would be far more helpful with images. Thanks