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How to Clean your Throttle Body

191K views 176 replies 88 participants last post by  tobyhd02 
#1 · (Edited by Moderator)
While changing oil today, I decided I would also pull the throttle body (TB) to clean it. My truck only had about 18,000 miles on it, but I thought I would check it out anyway to see how dirty it was. Here is the way to do this, if you want to do it. I've heard other members state that by 30,000 miles, the throttle body can be very dirty. Mine was not bad, but I am careful to use a Top Tier fuel and run a can of Sea Foam in the gas every few thousand miles.

1. Disconnect Battery:
This will help by resetting the ECM to accommodate the clean TB, and to ensure you don't accidentally short something out (although this is very unlikely).

2. Remove the Cover/Shroud:
The plastic cover over the engine is attached by 2 "buttons", like little compression fittings. It raises up, then toward the front of the truck to remove.
1 Cover Off.JPG

3. Remove the Intake/resonator:
Unscrew the clamp near the TB, and the one closer to the air cleaner/MAF. Then unattach the small line that runs into the side of the resonator (just twist and pull).
3 Remove Intake.JPG

4. Unhook the Electrical Connector:
Slide the small gray retaining clip back and remove. Push down (pinch) the connector, and pull back on the connector to unhook it.
4 Unhook Elec Connector.JPG

5. Unscrew the Bolts Holding the TB:
There are generally 4 bolts that hold the TB in place. On mine, the top 2 have nuts that are removed, and bottom 2 are bolts. Whatever combination you have, remove the 4 retaining bolts/nuts.
NOTE: There is a gasket behind the TB. Ensure you locate this as you remove the TB. Often, it sticks to one surface or the other.
5 unscrew bolts.JPG

6: Remove TB:
Carefully remove TB, and set aside. Note the location of the gasket (mine is green). Once removed, cover the area with a clean towel so no dust can enter the opening.
6 TB removed.JPG

7. Clean the TB:
Use a cleaner made specifically for the throttle body. Spray it from all sides, and allow the cleaner to work for a minute or so. Wipe it clean with an old lint free cloth. If needed, use an old toothbrush to remove all of the build up. NOTE: It is OK to move the butterfly (gently). Be sure to clean every side well. Allow it to dry before reassembly. This is also a good time to clean your MAF sensor: How to Inspect and Clean a Mass Air Flow Sensor (MAF)
7 Cleaning TB.JPG

8 Opening butterfly.JPG

8. Put it all back together:
Simply reverse the process. Bolt the TB back on, using a cross pattern (like mounting a tire). Plug in the elctrical connection to the TB. Attach the resonator, and be sure to plug the breather hose back in. Then put the engine cover on, and connect the battery.
 

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#5 ·
Great write up... I've heard that this is a very common GM truck issue for some reason. Sure has been a pain for my truck!
 
#7 ·
Can't wait to see what my TB looks like. I've never cleaned it and have never run seafoam through it either. My only saving grace is using TopTier gas.
 
#8 ·
Be prepared for a surprise, WN! I took the time the other night to clean my filter, MAF, and throttle body. Yowza, what a difference! Forgot how smooth the 6.0 is supposed to be.
 
#10 ·
Nice write up. After reading this, I ran out and bought the cleaners. The TB was DIRTY!!! I took it off and cleaned it on the bench. I also cleaned the MAF sensor.
I just got back in the house from a test drive. Seemed to be more responsive. I want to see how it reacts in the morning after cooling down in the garage. I have a slight throttle hesitation when cold.

Thanks again, Keith
 
#13 ·
JCunningham--
I understand what you are saying, but the carbon build up has to be coming from more than the filtered air coming through the intake. How do explain the gunk found on the TB?
 
#14 ·
Right on, Eric. I've done a lot of work with small engines, and those things always have some soft carbon buildup around the intake areas. It's not just dirty air; the inefficient burn that they use contributes to the carbon buildup. Same with truck engines- the carbon buildup around the TB and intake manifold is partly caused by the air coming in, but it's also coming from inside the engine itself. Plus, aren't all petroleum-based products dirt magnets? I might be wrong, but maybe the presence of gas in that area can attract dirt, too.
 
#15 ·
Correct me if I'm not reading into this properly, but these are side effects of EGR! Exhaust gas recirculation generally brings potentially carbon filled air back into the air intake to be sucked back into the system and in turn some of collecting on the inner (and possibly outer if it bleeds through) walls of the throttle body and intake system.
 
#16 ·
JCunningham said:
useing sea foam or top tier gas has nothing to do with the throttle body. the throttle body only has air going thru it.
Not true! The intake manifold can have byproducts of gasoline fumes inside. If you don"t believe, remove your throttle body and take a sniff.
 
#17 ·
EK, you so inspired me that I did my TB on the 04 Sierra 5.3L last week. Here are the photos and observations...

TB before it came off. Note the surface corrosion. The lead me to painting it...

If you are carefull and think it out, you can pull the bottom cooling line on the left side and quickly plug it with a 1/4" drive extension to minimize coolant loss. The line on the right side is long enogh to elevate above the radiator so so plug was necessary for that.

After removal, I noticed a small weep hole in the actuator body. Be carefull not to douse this with solvent. Who knows what's it for?

Here's it all masked up and cleaned.

Note that I plugged the weep hole with a smalled piece a rolled tape. A tooth pic would also work I suspect...

The materials used for the project. The Simple Green and an acid brush that was cut real short did wonders for all the nooks and crannies.

Painted outside in the sun and I cured it in the oven at 350 for a half hour. CAUTION: It'll stink up the house!

And here it is back on the engine. Looks so good, I may just paint the reast of the accessories...
 
#19 ·
Wow...took it to a whole new level! Very nice!
 
#20 ·
Thanks a lot, WN. Just another project to do, in order to keep up with you :roll:.

I'm really surprised you didn't paint it black :D! BTW, I've got that same multi-tool. Only the best tool EVER!!!
 
#21 ·
Its not necessary to remove the throttle body from the intake to do this as this can be done with the unit installed. Cleaning the throttle body only affects idle quality as the carbon build up can limit/restrict the air the flows past a CLOSED throttle (idle position). The engine ECU will adapt and compensate for this slow build up (by either slightly leaving the throttle plate a few thousandths of an inch more open at idle **for throttle by wire systems**- or by opening the idle speed controller a bit) so in most cases- the carbon build up won't pose any symptoms or problems and idle quality will remain stable. The only time it will show symptoms is if the battery dies or is disconnected and the ECU adaptation is lost. Once the adaptation is lost- the throttle plate ( or idle speed control motor) will go back to its default programmed closed position and the offending carbon build up will simply choke out the engine causing a rough idle or even stall out. It is important to disconnect the battery when performing this service because if the throttle body is cleaned and the adapted idle memory is not erased- the compensated idle position of the throttle plate or idle speed control will result in a higher than normal idle speed. This will not pose any real harm as the engine ECU will eventually adapt and "learn" to lower the idle speed over time- but until it relearns, shifting the transmission into drive or reverse can result in a harsh engagement due to the increased idle speed.
Anyone that thinks they suddenly picked up some lost power by doing this is suffering from the placebo effect.
 
#22 ·
Mostly good points, Joel. All I can add is to say I like placebo's. It's all I got, since they do random drug testing at work!

For as easy as this is to do, and for the opportunity to keep my truck squeaky clean inside and out, it's worth it to me. I was never saying it had to be done...just how it is done if you want to do it. As far as doing it while it's on the vehicle -- no thanks. I really don't want that spray going into gosh-knows-where in my engine, not to mention all the carbon that is being washed in there with it. Better to remove the TB, get it clean, and reinstall.
 
#23 ·
My post wasn't meant to be directed to you- it was more for general information for those that read the thread that might be reading it as a means of fixing an idle or stalling issue. Everything I said in my post is 100% accurate, however i do apologize if i made it seem like it was a rebuttal to your initial post.

Joel
 
#24 ·
No apologies needed...all opinions are welcome! :D
 
#25 ·
Joel

My 2008 is idling VERY high after cleaning TB and Mass Air as you stated in your post. 3000RPM at start and 1500 to 2000RPM in gear. I called the dealer and they said they would hook it to the computer for $97 to "relearn" the idle setting. They did say it could eventually learn it without the computer, but how long does it take? It's going to burn my break pads out if it keeps up too long.
 
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