Cleaning the throttle body
Thread Starter
Safety Car
Joined: Sep 2005
Posts: 4,222
Likes: 643
From: Orange County Ca
Cleaning the throttle body
My '08 LS3 now has about 100k miles on it and the idle may be a little rougher than before. I put in new plugs at about 70k miles. It seems to run well and it doesn't throw any codes.
I bought a can of maf cleaner and plan to use spray the sensor.
While I'm there, I think I might as well check out the tb.
The web info is all over the place, from just spraying it while on the car, to taking it off in order to get both sides.
Some say it's ok to rotate the plate and some say it will screw up the positioning sensor and the computer.
I've also saw that if I hold the gas pedal to the floor and hold start button, the car will not start, but turn on all the electrics, and the throttle plate will rotate to the full open position. ????
Some say a new gasket is a must and others say that the O ring type gasket is ok to re use.
So, to those who have done it, what do you think??
I bought a can of maf cleaner and plan to use spray the sensor.
While I'm there, I think I might as well check out the tb.
The web info is all over the place, from just spraying it while on the car, to taking it off in order to get both sides.
Some say it's ok to rotate the plate and some say it will screw up the positioning sensor and the computer.
I've also saw that if I hold the gas pedal to the floor and hold start button, the car will not start, but turn on all the electrics, and the throttle plate will rotate to the full open position. ????
Some say a new gasket is a must and others say that the O ring type gasket is ok to re use.
So, to those who have done it, what do you think??
Moderator, Tech Contributor
Joined: Sep 2013
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From: Cape Coral, Florida
You don’t have to take the TB off !!…the area on concern to clean is the bore not the plate..that is what you clean !!…key off will work and if you want to disconnect the TB motor…video below should help !!…when you hold the gas pedal to the floor while starting this is called a “clear flood crank” and it inhibits injector pulse so the car won’t start !!…I clean my TB maybe twice a year and never had an issue with an O ring…just get Carb cleaner or TB Cleaner and an old toothbrush and clean that bore…just open the plate with your fingers.
Last edited by C5 Diag; Jan 24, 2022 at 04:53 PM.
Race Director
Joined: Dec 2013
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Worry more about cleaning the Maf sensor, then cleaning the TB itself.
The TB only passes air through it, so light cleaning of it is more than enough in the first place.
If you still have the clean side of the PCV in play, it going to be oil fouled back up in a mater of weeks anyway.
The TB only passes air through it, so light cleaning of it is more than enough in the first place.
If you still have the clean side of the PCV in play, it going to be oil fouled back up in a mater of weeks anyway.
Melting Slicks
Joined: Nov 2011
Posts: 3,174
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From: Virginia
Do not force the tb blade open with your hand, turn the ignition on but don’t start the car. Have someone press the gas pedal to the floor and it will open the blade. Spray your cleaner on a rag and wipe the tb out good. This is what I do at least.
Moderator, Tech Contributor
Joined: Sep 2013
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From: Cape Coral, Florida
What damage will forcing the throttle blade open by hand do ??…this is how I’ve been doing it for years on all different kinds of cars !!…you risk getting your fingers crushed cleaning it doing a “clear flood crank”…NOT recommended unless you can open the TB with a bidirectional scan tool…I don’t even like using that method.
Melting Slicks
Joined: Nov 2011
Posts: 3,174
Likes: 259
From: Virginia
What damage will forcing the throttle blade open by hand do ??…this is how I’ve been doing it for years on all different kinds of cars !!…you risk getting your fingers crushed cleaning it doing a “clear flood crank”…NOT recommended unless you can open the TB with a bidirectional scan tool…I don’t even like using that method.
Moderator, Tech Contributor
Joined: Sep 2013
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From: Cape Coral, Florida
The gearing inside the TAC motor is free to move key off so I don’t see how the gears can be stripped…the TPS sensor if that what you’re referring to are just 2 potentimeters inside the sensor…nothing that can get screwed up…you have your method but I’ll stick to mine !!
Race Director
Joined: Jul 2005
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From: Central MO
The gearing inside the TAC motor is free to move key off so I don’t see how the gears can be stripped…the TPS sensor if that what you’re referring to are just 2 potentimeters inside the sensor…nothing that can get screwed up…you have your method but I’ll stick to mine !!
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Melting Slicks
Joined: Nov 2011
Posts: 3,174
Likes: 259
From: Virginia
The gearing inside the TAC motor is free to move key off so I don’t see how the gears can be stripped…the TPS sensor if that what you’re referring to are just 2 potentimeters inside the sensor…nothing that can get screwed up…you have your method but I’ll stick to mine !!
Instructor
Joined: Jun 2023
Posts: 101
Likes: 10
From: Poland
The gearing inside the TAC motor is free to move key off so I don’t see how the gears can be stripped…the TPS sensor if that what you’re referring to are just 2 potentimeters inside the sensor…nothing that can get screwed up…you have your method but I’ll stick to mine !!
Thanks
Video attached:
https://files.fm/u/4y9xmuurdd
Instructor
Joined: Jun 2023
Posts: 101
Likes: 10
From: Poland
I'm able to open it fully manually, but when the car is in maintenance mode with ignition on, if I press the throttle pedal so the maximum it opens like u see in the video. If im looking at the live data it shows it open max 56% , and when in idle it shows its 32.6% .
Moderator, Tech Contributor
Joined: Sep 2013
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From: Cape Coral, Florida
When you first cleaned it you were NOT in maintenance mode ??…I’ve cleaned many TB’s and have never had this happen…doubt it’s APP or TPS sensor issue but still may be something in the TB…I’ll look into this later.
Advanced
Joined: Apr 2024
Posts: 66
Likes: 18
From: Amarillo, TX
Don’t overthink the cleaning. I’ve sold hundreds of GM LS2/LS3 throttle bodies. I clean all of them all… blade, bore, casing; I recommend taking it off the vehicle so you can move the blade any way you want and actually get it clean. I primarily use water based degreaser and microfiber towel but for caked oil residue I use paint thinner. The electronics are sealed and TPS is mechanically linked to the blade. I’ve never seen an issue from this.
On aftermarket TBs, the TPS isn’t directly linked to the blade so I could see some rare issues with manually opening it causing the TPS to migrate.
I wouldn’t worry about any readings with the engine off. The TPS will read whatever motor input is from the ECM. Fire it up and check for codes, worst case, run a relearn or disconnect the battery for a few minutes.
On aftermarket TBs, the TPS isn’t directly linked to the blade so I could see some rare issues with manually opening it causing the TPS to migrate.
I wouldn’t worry about any readings with the engine off. The TPS will read whatever motor input is from the ECM. Fire it up and check for codes, worst case, run a relearn or disconnect the battery for a few minutes.
Instructor
Joined: Jun 2023
Posts: 101
Likes: 10
From: Poland
Thanks, cplease let me know what to check
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,562
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From: Cape Coral, Florida
Moderator, Tech Contributor
Joined: Sep 2013
Posts: 15,562
Likes: 4,034
From: Cape Coral, Florida
