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Carbon Buildup 101

Laimface

Ready to race!
Going through throttle body should work. Will be some interferences though. How many miles on car? I cleaned mine at 81,000 miles and they were nasty!

79k! I thrash the crap out of the car and run 98 oct fuel so hoping the buildup should be quite low
 

MMKAY6

Ready to race!
79k! I thrash the crap out of the car and run 98 oct fuel so hoping the buildup should be quite low

US 93 is the same as EU's 98 if you consider the RON vs AKI Octane rating. Gas shouldn't have a huge impact but trashing the crap out of the car could help aka Italian tune-up to blow out all that carbon.
 

GroceryGTIer

Drag Racing Champion
US 93 is the same as EU's 98 if you consider the RON vs AKI Octane rating. Gas shouldn't have a huge impact but trashing the crap out of the car could help aka Italian tune-up to blow out all that carbon.

Once it sticks to the valves, there really is no "blowing out carbon". It's a chemical reaction to the steel on the valves that causes the buildup
 

GroceryGTIer

Drag Racing Champion
I've been trying to make time to do the manual cleaning. I went and got injector seal kits the other day. I'm putting it off, but I need to get to it. High rpm misfires, mileage is way down, some cold start missing, but no codes. I'm really wondering if it's carbon, or if maybe my injector(s) are clogged, stuck, or leaking. I don't mind the actual cleaning, I just don't want to take all the crap off first lol. Has anyone done this without removing the entire TBP and just the hose?
 

Roadrunner_GTI

Drag Racing Champion
I finally got around to walnut blasting mine this past weekend. I have 67k miles and had been experiencing random misfires. The job took me about 10hrs, but I took my time and also replaced a few coolant hoses while I had the IM off. I did end up pulling the throttle body, but installed it on the IM before reinstall.

I went with a walnut blaster from Harbor Freight, connected to a BMW blaster wand with a modified shopvac attachment. Worked like a charm.

Side note: my 13MY GTI has the updated intake manifold with the revised runner flap stops.


Before and After


Before


After


New injector seals, and the cheap Ebay-special tool I used.


Blast wand setup I used.


Good time to change the oil after doing this job.
 
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GroceryGTIer

Drag Racing Champion
Does anyone lube the blue seals before putting the manifold back on? With what if so?

Also, does everyone put their manifold bracket back on? Thing sucks
 

Roadrunner_GTI

Drag Racing Champion
Does anyone lube the blue seals before putting the manifold back on? With what if so?

Also, does everyone put their manifold bracket back on? Thing sucks

Lube the blue injector seals with silicone free motor oil. Obviously do not lube the white Teflon seals. The manifold bracket is the trickiest part of the job. I installed it after the manifold was in place, given that seating the injectors is the highest priority. It's much easier with the TB removed.
 

GroceryGTIer

Drag Racing Champion
Lube the blue injector seals with silicone free motor oil. Obviously do not lube the white Teflon seals. The manifold bracket is the trickiest part of the job. I installed it after the manifold was in place, given that seating the injectors is the highest priority. It's much easier with the TB removed.

I put the white (teflon) seals on by hand and used a zip tie to tighten them, but I wasn't sure about which lubricant to use on the blue seals, obviously I don't want an issue with them.
 

mikedesamero83

New member
I was throwing a cylinder 3 misfire. I decided to try the cheaper fix: CRC GDI Intake Valve Cleaner. I have 80k miles.

1 month later: check engine light hasn't come back on, acceleration seems smoother, no rough idle.

Good fix for the price. I might spray another bottle after another 1K miles.
 

GroceryGTIer

Drag Racing Champion
I was throwing a cylinder 3 misfire. I decided to try the cheaper fix: CRC GDI Intake Valve Cleaner. I have 80k miles.

1 month later: check engine light hasn't come back on, acceleration seems smoother, no rough idle.

Good fix for the price. I might spray another bottle after another 1K miles.

It's very good for dissolving carbon, but to do really breaking down, 30 minutes of it sitting on a valve will do wonders, simply sweeping passed it won't do a whole lot. After cleaning mine manually the first time, I literally let the valves sit over 24 hours in b12 chemtool and even then, they had to be scrapped and cleaned with effort.
 

wmssbr10

Passed Driver's Ed
I was throwing a cylinder 3 misfire. I decided to try the cheaper fix: CRC GDI Intake Valve Cleaner. I have 80k miles.

1 month later: check engine light hasn't come back on, acceleration seems smoother, no rough idle.

Good fix for the price. I might spray another bottle after another 1K miles.

I had 80k no CEL's and no rough idle but was going K04 so did cleaning and tensioner. The valves were caked and gummy with carbon. A lot of 2+2 gum cutter and scraping was necessary to clean them up.
 

GroceryGTIer

Drag Racing Champion
I had 80k no CEL's and no rough idle but was going K04 so did cleaning and tensioner. The valves were caked and gummy with carbon. A lot of 2+2 gum cutter and scraping was necessary to clean them up.

If you use that GDI cleaner and let it soak, you hardly have to scrape it, same with b12 chemtool
 
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ben_m

Ready to race!
VW Huntington gave me a solid deal, I needed my intake manifold replaced and since they were already tearing into the car it only cost me 1.5hours in labor for the cleaning :) Not sure how bad it was, car was at 63k mostly local driving.
 

bruxwillix1

New member
apologize if this was already mentioned.. long thread.
but is it the general consensus that an induction service at the dealership does nothing? not even a good preventive measure? "pressurized atomizing" they're calling it. basically hooking up to a vacuum line with something similar to but i hope more hi tech then this
https://www.ecstuning.com/b-sur-and-r-parts/intake-system-cleaner-canister/srrfic903~srr/

thinking of getting 1 of those canisters and filling it with some CRC valve cleaner but did want to start with an induction service at ther dealer. unless my fellow enthusiasts advise otherwise....

Sent from my SM-G960U using Tapatalk
 
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