Originally Posted By: bourne
Originally Posted By: skyship
3.4% fuel is bad news although the rest of the UOA is fine, so no harm done. First question is do you get any smoke at hot idle or spend a lot of time stuck in traffic or short tripping?
If you do a few longer highway trips the fuel should evaporate, but as the normal limit is 2% I kind of thing something might be wrong with the injection system. It might be worth thinking about using a direct feed fuel injector cleaner to see if that helps lower the figure.
Are you using an OEM fuel filter and good quality fuel, as they are the main reasons for damaged or gummed injectors, along with simply not using the engine at least once a month?
If you can get the fuel contamination below 2%, then the OCI could be extended.
Its an engine quirk. Mazda DI is known to dilute their oils a bit. Any UOA on this website attests to that. Almost all of them show the oil between 6~7 cST @ 100C. Some even show dilution in the 5 cST ranges. The wear always looks good though. Makes me believe something I read on some Mazda forums a bit ago, one of the dealership techs mentioned that these engines are broken in from the factory, this helps it work well with the thinner oil they spec for the US and Canada markets I guess.
Many comments from some in here do not understand the Mazda Skyactive Engine. There is no problem with fuel dilution, you are correct, its a quirk, side product of being the WORLDS HIGHEST COMPRESSION GASOLINE ENGINE ... ( I guess some fuel slips through)and it runs on regular gas and super high mileage.
Anyone interested ... read up ... at this link ...
Mazda Skyactive engine
A new-generation highly-efficient direct-injection gasoline engine that achieves the world's highest gasoline engine compression ratio of 14.0:1
Features of SKYACTIV-G