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Member
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Join Date: Mar 2013
Location: Central IL
Posts: 449
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Member
Join Date: Mar 2013
Location: Central IL
Posts: 449
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Throttle Body buildup & need for cleaning
Hey all,
The other day I was working on a friend's car. The throttle body was so caked up with black buildup (carbon?) that it would stick. Sometimes open, sometimes closed. Either way, bad deal. While poking around and checking things out, we realized that the PCV valve was also stuck & clogged, so we cleaned that out with carb cleaner and the little ball now rattles around in there. (This may be relevant info to answer my question, but I don't know.)
While looking at the system, I'm a little stumped at exactly HOW this buildup accumulates on the throttle body and butterfly valve. It's just air -- filtered air -- passing through it. Fuel enters at the other side of the butterfly valve, and exhaust is on the other side of the engine. What is the source for the heavy black buildup, and would the clogged PCV filter play a role in this, and why?
I just don't understand how this would happen as I can see no lines from the crankcase or fuel system going to the air box before the butterfly valve.
Sorry for the rookie question. This is clearly something I should know after 25+ years of wrenching, but I just don't understand.
Last edited by Montego Murph; 12-02-2020 at 02:15 PM.
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