Automotive

Honda direct injection engine carbon buildup?

  • Last Updated:
  • Mar 13th, 2019 4:58 pm
Deal Guru
Feb 9, 2006
10875 posts
5210 upvotes
Brampton
ADRiiAN` wrote: K20 series motors are POS? That's a pretty bold statement. The B-series are fantastic though.
They are. Look at how many problems they've had since Inception. Only time will tell if they get even worse than they are now.
The 2000s were a dark time for Honda, people are free to ignore this.
Deal Expert
Feb 29, 2008
23550 posts
2855 upvotes
Montreal
engineered wrote: Typically you would regularly spray cleaner in your intake. Seafoam is popular, but ones with Techron are supposed to work better.
woof wrote: Only fill up with a Tier 1 gas.

But let me ask you this one question:
Where are all these posts from Honda owners complaining about horrible carbon build up on their DI engines?
er34er34 wrote: VTEC kicks the carbon off the valves. Exercise it regularly and you'll have no problems.
MoxGoat wrote: can of seafoam in the gas tank when it's half full. Buy either seafoam spray or any generic throttle body cleaner, take off the air intake and spray into the throttle body towards the valve. Activate the valve to get behind it as well. put down some papertowel or some cloths to catch any cleaner that comes out of the throttle body. After reattaching everything idle for a bit and go for a good drive (give it some gas to get any left-over carbon to come off the throttle body)

Ok. No idea how DI engines work. The only solution AFAIK, is walnut blasting if it happens.
burnt69 wrote:
No, it came out right. Its counter-intuitive to those who have been convinced, by years of marketing efforts, that more oil changes is better though.



The carbon build up is caused by the distilation products of motor oil which are at their greatest with virgin motor oil and gradually decrease as motor oil has been repeatedly subjected to distillation.

"clean" means that the oil hasn't been in service very long, and hence, has a much higher rate creating of distillates, which invariably end up in the intake. as vacuum is exerted by the intake on the crankcase through the breather and PCV systems.



Disagree. Used motor oil reduces the issue. Of course, if you run the oil change for dramatically longer than the maintenance reminder, for example, then there is the risk that the oil loses its lubricating qualities and causes damage to the components that it legitimately needs to lubricate. So best not to go crazy by significantly exceeding the maintenance reminder. Although used oil analysis from most Honda K24's on sites like Bobistheoilguy show that even at maintenance-minder intervals, that the maintenance minder is extremely conservative.
That's a prevalent belief on the internet yet I have seen no science to substantiate. What I read suggests the problem is poor crankcase ventilation with EGR emissions containing particulates and unburned gas that eventually makes up the sticky coating.

That's why most solutions rely on timing and ECU programming to avoid the problem, as opposed to some companies which have gone with a two stage injector system
Deal Addict
Oct 6, 2015
2407 posts
1309 upvotes
mr_raider wrote: That's a prevalent belief on the internet yet I have seen no science to substantiate.
There's a study or two that suggests that the intake deposits have chemical compositions awfully similar, in terms of metallic components, as motor oil additives. Manufacturers have also been moving "heaven and Earth" to get their customers to use higher quality motor oils, *and* to change them less frequently. They've also pushed the motor oil vendors to increase the quality of their oils considerably.
What I read suggests the problem is poor crankcase ventilation with EGR emissions containing particulates and unburned gas that eventually makes up the sticky coating.
Unburned petrol would not cause the coating. Actually unburned fuel would reduce the coating as fuel acts as a solvent. Its the motor oil along with EGR. Inducing crankcase fuel dilution may actually be partially a manufacturer strategy to deal with the issue, as petrol that gets into the oil is recirculated through the PCV.
That's why most solutions rely on timing and ECU programming to avoid the problem, as opposed to some companies which have gone with a two stage injector system
*and* prodding customers not to do the old-fashioned oil change intervals, or use inferior oils. Some of the worst examples seen online are people who serviced at their dealer every 3 months/3000 miles with cheap or complimentary oil changes. Which almost certainly are of the cheapest oil the dealer can lay their hands on, delivered in bulk, and not the official spec'ed oil. Lubricant fraud is unfortunately quite prevalent, and since dealers make good money fixing the problems after they've accumulated over the years through processes such as walnut blasting, aside from manufacturer auditing..

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