Have you noticed any Carbon Build-up with the 1.5T engines

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Hey Guys,

Since we have had about 5 years of time since this engine has been out I figured I could get some answers from some of you if you have experienced Carbon Deposits/Buildup on the valves for this engine? It's interesting because I read posts from folks on this board reaching 200k yet nothing about engine misfires or carbon build up, so that makes me question if Honda has done something from a design perspective within this engine to prevent the carbon deposits from building up.

@DRUSA feel free to chime in as well since you're a Honda tech that regularly works on these engines.
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VicVal01

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I remember reading about how Honda came up with a clever solution to the carbon buildup issue that DI engines are notorious for with the pcv system in order to burn any unburnt gas and thats why there is revhang.
 
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New to the forum but not DI engines, have lots of experience with Mazdaspeed3/6 engines as well as BMW N54 which are both DI and plagued by intake valve deposits. I did some searching here to see if the L15B7 had this problem as well. Found a lot of people talking about how the PCV system and DI injectors keep the valves clean.

I was pretty relieved to see all that but I recently bought an L15B7 out of a pull yard recently to familiarize myself better with the engine and when I pulled off the intake manifold I was greeted by a fair amount of carbon deposits going all the way down the intake tract. It's certainly not the worst amount of deposits I've ever seen but the engine is tagged as having only 5k miles which is mildly concerning. The heads of the valves aren't terrible so the injectors are likely doing something but the stems of the valves have a pretty large amount of deposits and the ports in the head are pretty nasty. My suspicion is that Honda has is using an EGR strategy with the valve timing (common on engines with VVT on both cams) so that may be something that could be tuned out.

I couldn't find anyone here who's actually taken the time to photograph their intake ports so figured I'd share my experience. All 4 ports look fairly similar. Took a pic with the valves open to show how thick the deposits are on the stems.

Honda Civic 10th gen Have you noticed any Carbon Build-up with the 1.5T engines intake port
 


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New to the forum but not DI engines, have lots of experience with Mazdaspeed3/6 engines as well as BMW N54 which are both DI and plagued by intake valve deposits. I did some searching here to see if the L15B7 had this problem as well. Found a lot of people talking about how the PCV system and DI injectors keep the valves clean.

I was pretty relieved to see all that but I recently bought an L15B7 out of a pull yard recently to familiarize myself better with the engine and when I pulled off the intake manifold I was greeted by a fair amount of carbon deposits going all the way down the intake tract. It's certainly not the worst amount of deposits I've ever seen but the engine is tagged as having only 5k miles which is mildly concerning. The heads of the valves aren't terrible so the injectors are likely doing something but the stems of the valves have a pretty large amount of deposits and the ports in the head are pretty nasty. My suspicion is that Honda has is using an EGR strategy with the valve timing (common on engines with VVT on both cams) so that may be something that could be tuned out.

I couldn't find anyone here who's actually taken the time to photograph their intake ports so figured I'd share my experience. All 4 ports look fairly similar. Took a pic with the valves open to show how thick the deposits are on the stems.

intake port.jpg
Awesome! I saw a video on youtube where someone showed the valves and the valve stems and head look great. They mentioned their car had 110k miles on it. I took a screenshot from the video. If you're curious it's this video and the timestamp for when he checks the valves are at 6:04. Pretty impressive I'd say!




Honda Civic 10th gen Have you noticed any Carbon Build-up with the 1.5T engines 1638815402048
 
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Wow yea that looks great for 110k!

Based on how wet those intake ports look I think a catch can maybe be beneficial even with the good baffling in the valve cover.

Yep exactly! Just curious, with the civic that you bought, was the engine driven in stop and go traffic a lot? Also what kind of oil was used? and was it filled with Top Tier gas? I think the build up on the stems on your specific engine could be one of these factors.
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