I have a 2018 Honda Fit with 36,000 mi. I have been changing the oil based upon the computer engine life analysis. At around 11,000, all of the idiot lights came on. This has been occurring sporadically since that time. The dealer has changed the injectors twice, and performed a top end cleaning using liquid solvents. Now they are going to change the head. They say this is a result of my having a direct injection engine. But come on now…this can’t be normal. What am I missing here…is the dealer being honest with me? How do you recommend I correct this problem. --Bob
This is common problem with direct injection engines. You can google carbon deposits direct injection for more information and tips on reducing the buildup.
Here is a brief how/why from one of the sites google took me to.
The main cause of carbon buildup on valves is that the added detergents and fuel don’t come in direct contact with the intake valves. It mainly happens because the fuel is injected directly into cylinders instead of a place behind the valve. As a result, the fuel and detergent are unable to clean the port and valve.
Luxus struggled with carbon build up on one engine series, but pretty much every new model has direct injection now and has for a while. I don’t think changing the heads every two years is a normal plan, nor do I think the dealer is correct. Over at CarComplaints, the Fit complaints are near zero for 2018 and 2019.
Are they asking you to pay? 36,000 is WAY too early to need a head cleaning, much less a replacement. And your powertrain warranty is 5 yrs/60,000 miles, so you should be covered.
Toyota and I think Ford now uses a combination of DI and FI system. When cruising the engine runs on in FI mode which helps keeping the valves clean.