Throttle body/iacv

LEXMICK · 10-07-09, 02:32 AM

Has anybody cleaned his Throttle Body/Idle Air Control Valve? I have done it on RX300 which has a different throttle body/IACV from RX330, following GoldenStateSilverSport's procedure from the other Lexus forum, by removing the right throttle body from the engine and I thoroughly cleaned them from too much carbon build up. The car is running great now.

But RX330 has a different type of Throttle Body/IACV and if anyone has done it, perhaps he could share some tips and pictures to save time and avoid unnecessary steps, even though the fundamental is the same.

arima · 10-07-09, 03:27 PM

be careful messing with the throttle could trip the check engine light, which requires an ECU rest.

yngexc · 10-07-09, 07:20 PM

I think the rx330 has drive by wire which equals not having a IACV.

LEXMICK · 10-08-09, 12:05 AM

I'm not sure about that. But I will remove the air duct to expose the throttle body and see if it doesn't have an IACV.

visual · 10-08-09, 08:36 AM

I cleaned the throttle body on my 05 RX last month. It was not complicated. You need to completely remove the horse with two clams that connect the throttle body and the air filter box. BTW, you can push the butterfly plate with your finger to make it open. Doing that you can clean the back of the plate. Once the plate is open, I would not spray the cleaner directly in the TB. You may end up flooding the system that way.

the most important thing to do after the cleaning is to reset the car's computer. Just remove the battery negative terminal for about 1/2 hour. The RPM will run high for the first 5 minutes, but it should settle down to normal RPM.

Good luck.

mandyfig · 10-08-09, 09:30 AM

Did you see an improvement?

LEXMICK · 10-08-09, 10:05 AM

Thanks for the info Visual. What we would like to confirm is if RX330 has an Idle Air Control Valve which should be attached to the throttle body like the RX300. I did remove the throttle body from where it is mounted when I did the RX300 a couple of months ago. That's how they do it in the shop to be able to clean it thoroughly and no need to worry about over spraying the throttle body. And I didn't have to reset the computer by disconnecting the battery's negative terminal. The car runs great after the process and I can tell there's a big improvement on idling and vehicle's acceleration response.

visual · 10-09-09, 12:47 PM

Quote:

Originally Posted by mandyfig

Did you see an improvement?

Maybe it idle smoother, but I can hardly tell the different.

visual · 10-09-09, 12:59 PM

Quote:

Originally Posted by LEXMICK

Thanks for the info Visual. What we would like to confirm is if RX330 has an Idle Air Control Valve which should be attached to the throttle body like the RX300. I did remove the throttle body from where it is mounted when I did the RX300 a couple of months ago. That's how they do it in the shop to be able to clean it thoroughly and no need to worry about over spraying the throttle body. And I didn't have to reset the computer by disconnecting the battery's negative terminal. The car runs great after the process and I can tell there's a big improvement on idling and vehicle's acceleration response.

There is a valve inside the throttle body. But I am not sure that is called the idle air control valve or not. Typically, I don't mess with removing the whole assembly to clean the TB.

LEXMICK · 10-17-09, 03:30 AM

yngexc is right. RX330 does not have idle control valve. It has an electronic controlled throttle which is called Drive By Wire. The device is attached to the side of the throttle body which controls the vehicles throttle and proper idling electronically. It makes it easier to maintain because you don't have to clean it unlike the idle control valve in RX300.

I removed the RX330's throttle body this afternoon and cleaned it of accumulated carbon. I replaced the mounting gasket with a new one, although the old one, I think is still fine and re-usable. The idle is back to normal at 750 RPM from almost 500 before cleaning. I'm very satisfied with the result.

joe913 · 10-19-09, 07:55 AM

How does one know when the time has come to clean the throttle body?

LEXMICK · 10-19-09, 12:19 PM

My RX330 had 35,000 miles when I cleaned the throttle body. You can also clean the MAF sensor when you're servicing your throttle body.

ohiois350 · 10-19-09, 02:32 PM

any pics? when you guy doing that, I want to do that for my 02 Highlander too, I think it has the same with rx300, but Iam kinda scary to do that, and what kind the tb cleaner should I use? thanks guy.

LEXMICK · 10-19-09, 04:13 PM

Hi Ohio,
Try this link. It is very helpful. http://us.lexusownersclub.com/forums...=Throttle+body

ohiois350 · 10-19-09, 10:19 PM

Thanks Lexmix for the link, I will looking to perform the tb cleaning for my highlander.