DIY - MAF Sensor and Throttle Body Cleaning
Instructor
Joined: Feb 2009
Posts: 1,199
Likes: 214
From: Ontario, Canada
Note that when you clean your throttle body, DO NOT move the flap by hand. This is why some people need to reset the ECU or have other problems. The throttle in the LS430 is drive-by-wire, meaning the flap is operated via a motor (not a cable) via the ECU, and the position of the flap is sensed via a precisely calibrated throttle position sensor. Moving the flap by hand can throw off the calibration and/or apply too much force to the throttle control motor or extend the flap beyond its normal range, which could damage the motor or cause the flap to not return to where the ECU expects it to.
The proper way to open the throttle body flap is to have someone press on the accelerator while the ignition is in the ON position. This is how the car naturally moves the flap, and there is no risk of throttle body control motor damage or throwing off the calibration of the throttle position sensor.
If you have an incorrect idle speed, it is quite possible (maybe even likely) that your throttle position sensor has become miscalibrated.
The proper way to open the throttle body flap is to have someone press on the accelerator while the ignition is in the ON position. This is how the car naturally moves the flap, and there is no risk of throttle body control motor damage or throwing off the calibration of the throttle position sensor.
If you have an incorrect idle speed, it is quite possible (maybe even likely) that your throttle position sensor has become miscalibrated.
Lead Lap
Joined: Nov 2002
Posts: 478
Likes: 0
From: NOVA-MD
SUCESSFUL MAF CLEANING
I recently purchased my LS430 (2003 with 118k miles) before even driving it I noticed it hesitated a little when reving it in neutral. The car idled smoothly and quietly. There was no CEL. As soon as I drove it the car fell on its face with anything over 1/3-1/2 throttle. The car would backfire sputter and wouldn't shift correctly. I quickly diag'd it as MAF related. I unplugged the MAF and it reved smoothly but wouldnt go over 3k rpm and kicked the CEL. I talked to my buddy at the Toyota dealer and he said to attempt to clean it before I buy a new one. $9 in parts (CRC cleaner) and about 30 mins the problem is fixed. Has been flawless for the past 700 miles. Quick easy DIY fix!
There was a good VID on youtube I followed.
PS- use a ton of cleaner, I used a whole can!
I recently purchased my LS430 (2003 with 118k miles) before even driving it I noticed it hesitated a little when reving it in neutral. The car idled smoothly and quietly. There was no CEL. As soon as I drove it the car fell on its face with anything over 1/3-1/2 throttle. The car would backfire sputter and wouldn't shift correctly. I quickly diag'd it as MAF related. I unplugged the MAF and it reved smoothly but wouldnt go over 3k rpm and kicked the CEL. I talked to my buddy at the Toyota dealer and he said to attempt to clean it before I buy a new one. $9 in parts (CRC cleaner) and about 30 mins the problem is fixed. Has been flawless for the past 700 miles. Quick easy DIY fix!
There was a good VID on youtube I followed.
PS- use a ton of cleaner, I used a whole can!
Driver School Candidate
Joined: Sep 2016
Posts: 19
Likes: 4
From: Georgia
And we're back to 350-400 rpm idle speeds. I wish I knew about not opening the valve by hand as that's what I did. Granted, I was having idle speed issues before, so I don't think I made it any worse. Is there a way to recalibrate the throttle position sensor?
Pole Position
Joined: Jun 2018
Posts: 2,415
Likes: 217
From: Ontario
Rookie
Joined: Aug 2015
Posts: 43
Likes: 14
From: Florida
You can use any sealant such as Toyota sealant, Threebond, Yamabond or other type sealant in substitution of a gasket in your situation such as this without problems. Just small coat where gasket sealed. Don’t smear so that it can drop into TB when dry.
CL Community Team
Joined: Aug 2011
Posts: 4,168
Likes: 1,006
From: Japan
Rookie
Joined: Aug 2015
Posts: 43
Likes: 14
From: Florida
When dealing with the tubing/hoses on your vehicles and the problems of location and just being old and hard. These tools will help. They are a staple in toolbox’s of most longtime mechanics. They will save skin and many hours of frustration over their lifetime when dealing with old and new vehicles.
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20% off coupons are readily available along with a free multimeter to throw in every glovebox/trunk.
https://www.harborfreight.com/3-piec...ers-37909.html
20% off coupons are readily available along with a free multimeter to throw in every glovebox/trunk.
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Driver
Joined: Jun 2019
Posts: 153
Likes: 54
From: FL
Note that when you clean your throttle body, DO NOT move the flap by hand. This is why some people need to reset the ECU or have other problems. The throttle in the LS430 is drive-by-wire, meaning the flap is operated via a motor (not a cable) via the ECU, and the position of the flap is sensed via a precisely calibrated throttle position sensor. Moving the flap by hand can throw off the calibration and/or apply too much force to the throttle control motor or extend the flap beyond its normal range, which could damage the motor or cause the flap to not return to where the ECU expects it to.
The proper way to open the throttle body flap is to have someone press on the accelerator while the ignition is in the ON position. This is how the car naturally moves the flap, and there is no risk of throttle body control motor damage or throwing off the calibration of the throttle position sensor.
If you have an incorrect idle speed, it is quite possible (maybe even likely) that your throttle position sensor has become miscalibrated.
The proper way to open the throttle body flap is to have someone press on the accelerator while the ignition is in the ON position. This is how the car naturally moves the flap, and there is no risk of throttle body control motor damage or throwing off the calibration of the throttle position sensor.
If you have an incorrect idle speed, it is quite possible (maybe even likely) that your throttle position sensor has become miscalibrated.
The reason for the high idle after cleaning is due to the ECU adjusting the TB over time to compensate for loss of air at idle as the idle air ports clog with carbon. Over time, the "default" idle position for the TB blade is greater than when new and/or clean. Once you clean the TB and those idle air ports are opened back up to original size, there's now more air coming into the TB which is still adjusted to the greater opening angle.
Soft rebooting the ECU via battery disconnect, or via the OBD2 port/scan tool, or cycling the engine on and off an X number of times, or driving the vehicle for an X number of miles will reset the TB position back to the proper angle which will naturally result in a normal idle RPM.
I had to do the same when I bored/polished the dual TB's on my 370Z, as well as cleaning the TB's on my friends Golf R, NC Miata, C6 Corvette and E60 M5 BMW. Pretty much any vehicle with driver-by-wire TB's will require this sort of reset after a good cleaning (or in my particular situation, boring/polishing).
Instructor
Joined: Dec 2015
Posts: 878
Likes: 232
From: Arizona
There's a poorly focused photo in step 3 of the original post that alludes to this.
Instructor
Joined: Feb 2009
Posts: 1,199
Likes: 214
From: Ontario, Canada
Yes, an old post, but also not correct. It has nothing to do with moving the TB blade by hand.
The reason for the high idle after cleaning is due to the ECU adjusting the TB over time to compensate for loss of air at idle as the idle air ports clog with carbon. Over time, the "default" idle position for the TB blade is greater than when new and/or clean. Once you clean the TB and those idle air ports are opened back up to original size, there's now more air coming into the TB which is still adjusted to the greater opening angle.
Soft rebooting the ECU via battery disconnect, or via the OBD2 port/scan tool, or cycling the engine on and off an X number of times, or driving the vehicle for an X number of miles will reset the TB position back to the proper angle which will naturally result in a normal idle RPM.
I had to do the same when I bored/polished the dual TB's on my 370Z, as well as cleaning the TB's on my friends Golf R, NC Miata, C6 Corvette and E60 M5 BMW. Pretty much any vehicle with driver-by-wire TB's will require this sort of reset after a good cleaning (or in my particular situation, boring/polishing).
The reason for the high idle after cleaning is due to the ECU adjusting the TB over time to compensate for loss of air at idle as the idle air ports clog with carbon. Over time, the "default" idle position for the TB blade is greater than when new and/or clean. Once you clean the TB and those idle air ports are opened back up to original size, there's now more air coming into the TB which is still adjusted to the greater opening angle.
Soft rebooting the ECU via battery disconnect, or via the OBD2 port/scan tool, or cycling the engine on and off an X number of times, or driving the vehicle for an X number of miles will reset the TB position back to the proper angle which will naturally result in a normal idle RPM.
I had to do the same when I bored/polished the dual TB's on my 370Z, as well as cleaning the TB's on my friends Golf R, NC Miata, C6 Corvette and E60 M5 BMW. Pretty much any vehicle with driver-by-wire TB's will require this sort of reset after a good cleaning (or in my particular situation, boring/polishing).
After a cleaning, you should do a 10 minute battery pull (my copy of Techstream and/or my cable cannot clear my Canadian 2002's ECM/PCM memory/learned values, but a battery pull is guaranteed to work), followed by 5 minutes of idling in the driveway, followed by a 20 minute drive in-town. If your idle is still incorrect and your idle ports are clean, throttle plate is clean, and there is no cleaner residue/vapors in the MAF or inside your throttle body, you probably knocked your TPS out of calibration, damaged the throttle position motor, and/or damaged the MAF during cleaning.
