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Discussion Starter · #1 ·
This is just more of an FYI reminder for those not in the know and DD your G8, especially if you are getting up over 60-80k miles on your G8. I just hit 107k miles and realized I hadn't cleaned the MAF or TB in about 40k miles. Holy crap did it make a difference. There was a ton of carbon buildup on the TB. It took about 20 minutes to disassemble, clean, let dry and re-assemble. The throttle response change was immediate and noticeable. I was also getting a little bit of a rough idle, which is another telltale sign this is needed. It costs about $10 in cleaning fluids (MAF specific spray and TB specific spray). My MPGs also have jumped back up to normal, about a 1.5mpg increase!

Some basic pointers for those who have never done it.

Do not touch the finite wires in the MAF with the spray straw or your hands...or touch it with anything.

Do not spray the MAF while on the car, just remove it and let it sit on a towel to dry. Do not dry it with a rag, just spray it and let it sit for a few to air dry.

When you clean your air filter is a good time to do this. It really could/should be done every 15-20k miles, but I let it slip:(
 
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never thought to do the TB as-well... might do it here soon! is it easy to get off and any wires off? any problems to re-assemble?
 

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Discussion Starter · #3 ·
I did the TB on the car. Our TBs are electronic so there is no linkage. You could take it off, but 99% of the carbon build up is where the smoothed portion around the throttle blade is and easily reached while the bellow elbow is pulled off the TB. I just sprayed the cleaner on a clean shop rag and wiped inside with my fingers while using the other hand to push open the blade. I had to put a little effort on it to get it off. You won't hurt it by opening it. If you take it off the car, it's really just a couple of bolts and unplugging the connector going into it. There is a lifetime O-ring seal so you won't have to replace a gasket...

Here is a youtube vid on changing a TB on a 5th gen Camaro SS, very similar to our engines...
https://www.youtube.com/watch?v=G-pUj4DdcbA

Also, just be sure to not spray a ton of that stuff directly into the intake as it will make for a rough start when you turn the key over and many TB cleaners can damage some plastics, hence why I used the clean shop rag.

I should have done a photo before and after write-up.

I did this on my supercharged silverado ss regularly before too.

http://www.popularmechanics.com/cars/how-to/repair/1272341

Here is a video on "how to" on a GM I6 trailblazer motor...getting the TB off is obviously different, but similar cleaning process...
https://www.youtube.com/watch?v=VdvgsaDmkac
 

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An alternative to pushing open the blade / butterfly valve would be:1. Turn the ignition to on (engine off). 2. Place a brick or similarly weighted object on the accelerator which will move the valve electronically versus manually. Just my $.02.
 

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Just put a volant on mine last saterday and mt TB was nasty black carbon. Espaclly the butterfly, mine only has 28k on it.Didn't know it was that easy to take off, I will clean it that way next time.
 

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the maf i agree with 100% but how exactly is cleaning the tb going to help...???
 

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Discussion Starter · #7 ·
the maf i agree with 100% but how exactly is cleaning the tb going to help...???
Dirty throttle bodies can cause rough idle even when warmed up, sometimes even leading to stalling or near stalling symptoms when coming to a stop, rough idle on start up, lagging throttle response and it has even been proven to reduce HP by anywhere from 5-15hp, plus reduce mpg's as a result of all of that. The "gumming" can cause the butterfly valve/blade to somewhat stick a little bit when trying to open, also when it opens just a little bit, the gummed up ridge formed can close the opening off completely...that is what can cause the stalling because the TB blade might be closed most of the way as engine power is reduce when coming to a stop, but the formed ridge completely closes it off and the engine stalls out. Also, if the buildup gets real bad, it can reduce the opening by a mm or two, cause turbulence/disturbance in airflow, etc. This is all well documented in TSBs and dealers would charge you up to $200 to clean it/fix it.
 
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Good to know gang. Thanks for the heads up on the tb.
 

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going to clean the MAF and TB this weekend! I'm at 71,000 miles so I need it!

Thanks for letting us know!
 

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Thanks for this. I'm at about 101k myself. Is there anything else that should be cleaned or changed at 100k miles?
 

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Cleaned them both today! Was pretty easy beside the clip on the throttle body was a little tough to get off.

Here are some after photos:





Sorry I have no before photos, it was pretty dirty though.
 

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Discussion Starter · #13 ·
And did you notice any throttle response difference or difference in idle quality?
 

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And did you notice any throttle response difference or difference in idle quality?
When I started it up the idle was nice and smooth! The throttle response felt the same but the car overall felt really solid. I got on it a couple times and it pulled very hard, better than before. I only drove for about 10 minutes though.

I wish I would have taken before photos but it was pretty dirty, had a nice think black line around the valve that opens and closes with a bunch of brown gunk surrounding it. The cleaner did a nice job though, happy with the results.
 

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Discussion Starter · #15 ·
:gears:
 

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Dirty throttle bodies can cause rough idle even when warmed up, sometimes even leading to stalling or near stalling symptoms when coming to a stop, rough idle on start up, lagging throttle response and it has even been proven to reduce HP by anywhere from 5-15hp, plus reduce mpg's as a result of all of that. The "gumming" can cause the butterfly valve/blade to somewhat stick a little bit when trying to open, also when it opens just a little bit, the gummed up ridge formed can close the opening off completely...that is what can cause the stalling because the TB blade might be closed most of the way as engine power is reduce when coming to a stop, but the formed ridge completely closes it off and the engine stalls out. Also, if the buildup gets real bad, it can reduce the opening by a mm or two, cause turbulence/disturbance in airflow, etc. This is all well documented in TSBs and dealers would charge you up to $200 to clean it/fix it.
thanks

it's on my list as i'm nearing 83K and am about to do a tuneup and install a vcm intake
 

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ok I cleaned my TB this morn now i threw a code P0507 IAC circuit condition or idle speed higher/lower than expected. i posted a new thread about the spiking idle. is it to clean? haha
 

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Discussion Starter · #18 ·
Disconnect your battery for about 10-15 minutes to reset your PCM and see if the code comes back. When did you get your tune done?
 

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Some GM's after throttle body clean will have the issues you are describing. What I usually do to correct it is...

1. Turn ignition on (engine off)
2. Press and hold the accelerator pedal down all the way for 5 seconds.
3. Let go of the accelerator pedal
4. Turn ignition off
5. Start engine let it idle on its own in park for 5 minutes without touching pedal

Good luck I hope this helps
Sent from AutoGuide.com Free App
 
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