Vtec engine has a very well-engeneered egr deposit chamber on the intake manifold. Cleaning deposit is a must-do manteinance operation, but O do not recall having been suggested in Honda manteinance program. I found my egr ducts in the intake manifold completely clogged. Car has been regularly serviced by Honda dealers but none ever did or suggested to do this very simple operation on 13 years and more then 300k Kms. No error codes were ever recorded and related to this, but I can swear that engine behaves much better after. If is so important why is not routinely recommended? I had also a GD DSi engine car before this and it clogged the intake manifold in a different place (near the intake port of the head). Car started to sputter and misfire. I took car to dealer as other mechanic told me probably head valves or a piston were gone. They immediately pointed to the problem and solved it quickly and almost inexpensively. When I asked if the GR vtec model could have the same problem they swore not needed it. False to my knowledge. Only need a simpler and more efficient clean. Do it without doubt if you are over 100k Kms.
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So I guess yours were dirtier than mine cause I didn't have any clogs. Maybe because I used seafoam through the brake booster vac line a couple times.
https://www.fitfreak.net/forums/2nd-...-passages.html

 

I do not know how fast the deposit build up. It could depend on how car is used or what gas you put in. My chamber was completely blocked on both sides of the gasket, leaving no space for gases to recycle in the inlet manifold. From what I see in your picture the chamber is dirty but holes are not blocked. This is the right time to clean it as a preventive manteinance schedule. Later on, the build up could be faster, having a base for sticking up.I doubt seafoam would be of any utility as long as the exhaust gases and not the unburnt seafoam would find its way in those passages. I simply don't know but I am grateful to the Honda engineer who devised a way to collect the deposit in a simple easy to find place. They just forgot to mention it in the workshop manual, but design is very effective.The metallic gasket of the "box" can be reused a couple of times if properly cleaned as long as the two aluminium adjoining surfaces are well cleaned.I noticed one more thing doing this extra cleaning: the aluminium base of the EGR valve on the manifold shows clear signs of erosion around the hole were the gases were coming from the exhaust. Probably the lack of circulation rised temperature too much on the spot and allowed the tender aluminium to start deforming.

 

Seemed like an easy enough task, so I inspected my EGR valve and ports. Both looked about the same (sooty with no significant build-up.) I spritzed and wiped off the EGR valve with throttle body cleaner, but I just put the port cover back on after snapping a few pics (sorry for the blur.) 236,000 miles (all mine). FWIW, I say hello to VTEC almost every time I drive it (that's a Japanese tune-up, I guess.)

 

@zcargo Thanks, Z.

 

I was thinking about this today. Are there still people on this forum who are afraid to drive their cars? I hope not.