Took the opportunity to clean MAF and TB on our other car this weekend and it was a quick 30 minute job so I decided to do the LS also.

I had bought a can of CRC MAF cleaner and a can of CRC throttle body cleaner (approx $5/can).

Took the MAF out (very easy, disconnect electrcal connector and loosen 2 screws) and sprayed it down - total time 5-10 mintes. The MAF looked pretty clean but I cleaned it anyway, let it dry for 2 minutes and then reinstalled. Based on where it sits in the airflow between airfilter and TB, the MAF should never get dirty unless your filter fails or the airbox isn't correctly closed and latched/sealed.

Then took the plastic engine cover off (2 round head bolts , then took off air cleaner box by loosening the main hose clamp and disconnecting throttle body large rubber air intake hose from the throttlebody itself (loosen clamps on both ends of the hose). It also requires removing 1 10mm bolt on the rebreather plastic box that is attached to the main TB air intake hose. To get that box and attached hose completely removed I also disconnected 2 PVC rubber hoses - 1 large hose and 1 small hose that are connected to rebreather box assembly. Sounds complicated buts it very simple and easy.
Once I had room to work, I lightly sprayed down the outside of the throttle body butterfly valve - there was just a small bit of dirt on it and the outside surfaces of the TB port. I then opened the valve with a finger and cleaned out the interior using several paper towels wetted down with TB cleaner. There was some significant but not huge amount of oily gunk to clean out just inside and past the butterfly valve opening on the bottom and top insides of the TB port just past the butterfly valve. Continued wiping with cleaner saturated paper towels until I got no more black oily residue showing on the towels.

The car has 30k miles on it and I would say the TB really did not need cleaning as the car was still running smooth. However the process is so easy that I will likely do the cleaning again at 30K intervals. Probably slightly increases gas mileage also.

Reassembly of TB hose and airbox took another 10 minutes. Total time for entire process less than 45 min and I took my time and cleaned and vacuumed all misc parts (engine covers, filter, filter box, TB hose assemble, top of engine, etc) before reassembling.

Car runs very smooth now. Used maybe 1/5 can of MAF cleaner and 1/3 can of TB cleaner.

Lexus I think charges like $120 for this - it is an easy 45 min DIY, quick and materials cost is approx 3-4 dollars max. On the LS, the TB is right up front on the motor so it is very easy to get to and clean. On the Highlander we have, cleaning the TB was more difficult and harder to reach as its on the back side of the motor and requires disconnect a little more more stuff.

 

I did the same when I changed plugs,oil and oil filter last time on my own car. My car has 107k km (just over 60k miles) on it and the TB needed a good clean,it had quite a bit of gunk in behind the butterfly,and an expected level of crud on the butterfly itself.

One suggestion for next time - to use a cotton rag,like an old t shirt. paper towel will generally leave lint-like 'bits' behind,which will get sucked into the engine.
You can also apply more pressure when wiping with a rag,and can sparay the carby/tb cleaner directly onto it first,and then poke it in and up behind the butterfly to give it a thorough wipe down.


Justin...

 

Justin - Good suggestion. I was careful with the paper towels, using multiple paper towels and making sure they did not shed or tear. But I agreed that clean shop rags would have been preferable to use as they are not likely to shed bits into the engine air intake and can take more pressure and use.

Fortunately on my car (with only 30k miles) the gunk was soft and pretty limited and came off easy with TB cleaner wetted paper towels.

 

Thanks for pointing this out.

I consider this good "preventive maintanance" - you are able to remove the "gunk" while its at a thin film stage, and not waiting till it turns into a carbon hard headache that you need a brass bristle brush to remove.

The MAF sensor is in direct contact with the airflow - including humidity/moisture/acid content that comes along with it. that's the stuff you can't really "see" on the MAF sensor but after 30k miles or 3 years it does have an effect on the sensor - so regular cleaning of that component is actually a crucial item to add to your maintanance schedule.

 

Marklouis - interesting info you posted on the MAF getting dirty even in the "filtered"airflow. Makes sense now that you point it out. Given how easy it is to pull the MAF and clean it, its certainly something I will do when I change air filter once a year so that should be plenty.

 

just cleaned my TB and MAF last weekend - amazing how easy the procedure was. the removal of the TB from the manifold was one of the easiest TB's I ever removed. I was able to clean the TB very thoroughly that way.

 

so the MAF sensor thing is on the hose between the filter box and the motor but on the side technically right? anyone got a pic they can point to just to make it crystal clear in my head... thanks, i'm gonna clean both this weekend hopefully.

 

Would be great if someone has pictures showing where are these two items. Thanks in advance.

 

My can of CRC MAF Cleaner states:

10 DO NOT use on vehicles with Karman-Vortex air flow sensors e.g. Toyota Supra Turbos, Mitsubishi and most Lexus vehicles.

So what kind of MAF sensor do we have in our LS430's... hopefully not this type.

Anyone have the intel?

 

I did a little research and I think LS430 does not use a Karman-Vortex air flow sensor at least based on looking at the design - but I am not an expert. I could be wrong. I can say that I used the CRC MAF cleaner to thoroughly clean the MAF on my 2006 LS430 about a month ago and have had no problems.

This thread is from RX forum - the MAF depicted looks 100% identical to the one in the LS430.
https://www.clublexus.com/forums/rx-...-cleaning.html

 

OK, I'll be bringing this MAF cleaner back to the store and backing away slowly!

TOYOTA & LEXUS APPLICATIONS
Karman-Vortex airflow sensors are used on 1987 and later turbocharged Toyota Supras, and all Lexus engines except the ES 250 and ES 300.

http://craftautoparts.com/karman_vor...w_sensors.html

I wonder what the dealers use then if anything at all?

 

Found this thread after searching for a minute... Curious as to see if anyone knows anything more about which cleaner to use for a DIY cleaning of throttle body and MAF sensor?

 

I understand that the CRC MAF cleaner has a warning against using it on some types of MAF. If you are concerned I'd call Lexus dealer and ask what they use to clean the MAF on an LS430.

All I can relate is anecdotal - I have used the CRC MAF cleaner on both my 07 Highlander and 06 LS430 twice to-date with absolutely no problems.

The CRC brand TB cleaner (or any spray labeled for TB cleaning) can be used on LS 430. I have cleaned the TB on my LS twice using the CRC TB cleaner spray with absolutely no problem.

 

I'd recommend any 'carby and EFI parts' cleaner for the TB,and electronic contact cleaner for the MAF.


Justin...

 

My LS has 124K miles on it. I cleaned the Throttle Body and the MAF. The TB was really dirty with gunk on the butterfly and the inside of the cylinder on both sides of the butterfly.

I noticed that my car now idles around 1100 RPMs. Does the computer need some time to readjust? I haven't driven it anywhere yet. Runs smooth though.


Update:
I pulled the battery cables and reset the ECU. It idles just fine now.