MAF Sensor and Throttle Body Cleaning DIY: GS400 & GS430
05-27-14, 05:33 AM
#76
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CLARIFICATION AS REQUESTED FOR UDEL
1. Vacuum recovery box bolts (2 total). One bolt is facing the passenger tire side, as you've found. The other is on the side that faces the main firewall towards the dash (think of a straight line on the vacuum box, starting from the front bumper straight to the car's front console dash--the bolt is on the far end of the plastic vacuum box, closest to the firewall/interior cabin). See attached pic from another post (courtesy of e-man) that I modified for clarification.
2. Vacuum hoses and loosening (3 total). The Lexus schematics in this post should be pretty clear on which ones you need to remove. You will need to slide the metal clamps about 1" away from the edges before you can move the hoses off--you do this by first squeezing with pliers the metal clamp ends together (which makes them larger) and then you can slid them away from the ends of the hoses. To get the hoses off easier, I suggest that you first TWIST left and right the hoses, then pull them off. If you try to pull them off without loosening them by first twisting, they'll be very hard to get off (esp. the thick PCV hose which has a longer end attachment).
3. Intake hose loosening (the end that attaches to the throttle body on the engine). First, loosen the compression clamp. Again, TWIST the whole tube end, you may have to gently push the rubber end lips a little at a time to get it to twist off. It does come off--no glue is holding it in place (it's attached like the other end to the air filter box). It's probably never been removed on your car before, hence why you're having such a problem--have faith, it does come off
1. Vacuum recovery box bolts (2 total). One bolt is facing the passenger tire side, as you've found. The other is on the side that faces the main firewall towards the dash (think of a straight line on the vacuum box, starting from the front bumper straight to the car's front console dash--the bolt is on the far end of the plastic vacuum box, closest to the firewall/interior cabin). See attached pic from another post (courtesy of e-man) that I modified for clarification.
2. Vacuum hoses and loosening (3 total). The Lexus schematics in this post should be pretty clear on which ones you need to remove. You will need to slide the metal clamps about 1" away from the edges before you can move the hoses off--you do this by first squeezing with pliers the metal clamp ends together (which makes them larger) and then you can slid them away from the ends of the hoses. To get the hoses off easier, I suggest that you first TWIST left and right the hoses, then pull them off. If you try to pull them off without loosening them by first twisting, they'll be very hard to get off (esp. the thick PCV hose which has a longer end attachment).
3. Intake hose loosening (the end that attaches to the throttle body on the engine). First, loosen the compression clamp. Again, TWIST the whole tube end, you may have to gently push the rubber end lips a little at a time to get it to twist off. It does come off--no glue is holding it in place (it's attached like the other end to the air filter box). It's probably never been removed on your car before, hence why you're having such a problem--have faith, it does come off
thanks
05-27-14, 05:39 AM
#77
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Hello, I have two broken and disconnected hose box, I see the RPM without A / C is very low (400 RPM), it influences those broken hoses in the operation of the car and the gas consumption?.
thanks
thanks
06-04-14, 06:33 PM
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CEL came on my 2002 GS430 with 112K miles reporting code P0171. Used the CRC MAF Cleaner as instructed here and WOW! Car runs soooo much better! Light is off now too! Cannot believe such a quick and inexpensive fix had such a huge impact on the performance! Thanks to all that have contributed here!
07-29-14, 01:32 PM
#79
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Many thanks to the OP and the contributors on this thread. I was able to clean my MAF and throttle body with very little difficulty last night and I wished to simply add a few observations.
The discussion has presented the option of leaving the throttle body attached and opening the butterfly valve to clean as well as can be done in this position or to remove the whole assembly after detaching all attachments. I believe a third option I did may be the best of both worlds, but I can see how either of the other options would be appealing for different reasons.
I found that by removing the hoses which did not allow enough slack to slide the throttle body forward and just off the mounting bolts and leaving attached those that did, as well as the throttle cable assembly, I could rotate the throttle body towards myself in a way that allowed me access to clean both sides of the entire throttle body, without bothering to detached all the attachments. I am now wishing I took a pic of the setup. Essentially I lay a clean shop rag tucked beneath the rotated throttle body to catch any cleaner which dripped through and used another rag soaked with cleaner to wipe clean everything. It takes some time for the cleaner to break down and remove all the gunk, but not that much effort. I replaced the gasket and there was enough room to slide it off and on.
MAF sensor cleaning was incredibly easy, period. RPM’s ran a bit high initially but appear to have gone back to normal or perhaps very slightly still above. I have read others have experienced this and I will look for them to return to normal. I did spark plugs at the same time and am planning to do injector cleaning as well. So far the engine feels like some life has been revived.
Finally, needle nose pliers for the hose clamps are very helpful. Thanks again.
The discussion has presented the option of leaving the throttle body attached and opening the butterfly valve to clean as well as can be done in this position or to remove the whole assembly after detaching all attachments. I believe a third option I did may be the best of both worlds, but I can see how either of the other options would be appealing for different reasons.
I found that by removing the hoses which did not allow enough slack to slide the throttle body forward and just off the mounting bolts and leaving attached those that did, as well as the throttle cable assembly, I could rotate the throttle body towards myself in a way that allowed me access to clean both sides of the entire throttle body, without bothering to detached all the attachments. I am now wishing I took a pic of the setup. Essentially I lay a clean shop rag tucked beneath the rotated throttle body to catch any cleaner which dripped through and used another rag soaked with cleaner to wipe clean everything. It takes some time for the cleaner to break down and remove all the gunk, but not that much effort. I replaced the gasket and there was enough room to slide it off and on.
MAF sensor cleaning was incredibly easy, period. RPM’s ran a bit high initially but appear to have gone back to normal or perhaps very slightly still above. I have read others have experienced this and I will look for them to return to normal. I did spark plugs at the same time and am planning to do injector cleaning as well. So far the engine feels like some life has been revived.
Finally, needle nose pliers for the hose clamps are very helpful. Thanks again.
07-02-15, 03:48 PM
#80
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03-02-18, 08:07 AM
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Great post
I know this is an old thread but helped me to to do the cleanup on 2007 Lexus GS350 140K. Great post. Thanks
It did not seem like they were that dirty but we shall see how it helps out.
The timing was perfect as I going to change spark plugs as well.
It did not seem like they were that dirty but we shall see how it helps out.
The timing was perfect as I going to change spark plugs as well.
03-02-18, 10:24 AM
#82
Thanks for bumping this thread. I cleaned my TB ( not sure about the MAF sensor) a few years ago. I'll probably do it again this weekend and also change out the sparkplugs. Been checking old threads and will probably go OEM Denso SK20R11 Iridium Long Life or see if I can find the Torquemaster (PN#?) spark plugs somewhere. All I have is an SRT intake on my GS400, so I think the TM should work since there aren't any other engine mods.
04-15-18, 07:50 AM
#83
Thank you for posting this.
I've noticed my 2001 has a slight hesitation at WOT. I'll be cleaning the MAF/TB and replacing the spark plugs. I changed the air filter this weekend as it was pretty dirty.
I've noticed my 2001 has a slight hesitation at WOT. I'll be cleaning the MAF/TB and replacing the spark plugs. I changed the air filter this weekend as it was pretty dirty.
11-24-18, 09:29 AM
#84
PSA for this thread:
On top of the GS400/430 throttle body is a little plate held down by two screws. If you take this plate off you’ll probably find the little chamber full of carbon crud. Clean that crud out as part of the TB cleaning! There should be a little row of holes in the bottom of that tiny chamber, and two ports in the back of it. Stick the spray straw down those ports and blast them out.
I came across this buried deep in another thread, but this little chamber is an idle air flow thing. My TB was fairly clean but cleaning out the idle chamber thingy made my car start up much faster.
On top of the GS400/430 throttle body is a little plate held down by two screws. If you take this plate off you’ll probably find the little chamber full of carbon crud. Clean that crud out as part of the TB cleaning! There should be a little row of holes in the bottom of that tiny chamber, and two ports in the back of it. Stick the spray straw down those ports and blast them out.
I came across this buried deep in another thread, but this little chamber is an idle air flow thing. My TB was fairly clean but cleaning out the idle chamber thingy made my car start up much faster.
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