Correct Throttle Body Cleaning Procedure?

[Super77]

Good and proven write-up or video? @2001LC you must know your way around these? I'm doing the LC and my 90K mile Lexus SC430 with a 3UZ-FE. From what I've read, they're nearly same geometry. They have never been cleaned AFAIK and the SC is idling rough.

Questions:
- On-car or off-car? Take the time to remove?
- OK to move the throttle plate or don't touch it? How big a deal is the ECU position re-learn procedure?
- Idle air chamber (that little rectangular box with a gasketed cover and tiny holes inside) - scrub it clean if dirty?
- What chemicals to use? I have some CRC TB cleaner.
- Anything worth checking/doing in the intake manifold if I have the TB removed?

 

[leveeguy]

I've always cleaned while on-car. Disconnect battery negative first.

I spray cleaner onto clean rag/blue shop towel, manually move throttle plate and hold open to clean slightly behind the throttle plate. Most difficult part might be cleaning the top of the throttle body just bc its harder to see the top area. I clean the face/edge of the plate and the mating surface.

Its a quick easy procedure that can be done once/twice a year with little effort when kept clean. Just be sure not to lose pieces of your cleaning rag behind the plate and all will be good. The cleaner you have is correct.

Reconnect battery and start vehicle. May require two attempts to start for first start afterwards, nothing to be alarmed of if so.

 

[Super77]

Yep, that's more or less what I have read, but is it really ok to move the TB valve by hand?

 

[leveeguy]

I cant say I'm aware of any other way to move it with engine off and battery disconnected.

It has to be moved to accomplish the cleaning.

 

[kbfj621989]

Disconnect the battery and I’ve always made a conscious decision to not make any rapid manual movements of the plate so that any electronics are not damaged.

 

[juicemode]

I don’t know if my procedure is correct or not but use the key in the on position then depressing the gas pedal will move the butterfly to fully open then I clean both sides.

 

[OEMGUY0720]

Disconnect the (-) battery terminal before removing the TB assy.
Once removed, clean the butterfly and cylinder from any carbon deposits.
Air flows like water so if there is a high or low spot on the cylinder wall or butterfly surface, that will cause turbulence hence air will not flow efficiently.
Keep it simple, clean the surface where the air flows, surface must be flat with little to no obstruction.

 

[Dirt J]

This seems legit but can't place the original source easily. Looks to be a Toyota document.

Here's 2001's writeup.

EDIT: I clean mine without removing from the truck FWIW. Removing would probably allow for a more thorough job though.

 

[excessive]

i had heard somewhere (not sure where) that it's not good to move the TB butterfly manually, its better to use the gas pedal to move it.
not sure it that's true or not.