Gasoline Direct Injection

[Harold_J]

I notice that more automobile manufacturers are going to the direct injected gasoline engines. My sister's 2012 Hyundai Sonata has it.

I have a 2011 Mazda that gets about 29 MPG overall. I really like the car but it's tempting to look at the later 2013-2014 Mazda models with direct injection (Skyactiv) that can get 10 mpg more.

Is this gasoline direct injection reliable in the long run or will it eventually run into expensive repairs similar to some new diesels because of the very high pressure fuel system designs being used?

 

[Peacock]

Hard to say at this point. GM has been using it for a decade or so. Others have slowly started using it.

The parts are going to be more expensive. Not sure yet how the long term reliability is going turn out. The problems I've seen related to it are generally due to deposits on the intake valve and fuel dilution. BMW has had some real issues with build ups on the intake valves. Believe GM calls for a top end clean at certain intervals for just that reason.

 

[JasG]

The system is no where near the same as a common rail diesel so it is hard to make a good comparison. I've read direct injection gas is between 1700 and I've seen as high as 3000 PSI. The current Diesels are 25000-32000 PSI. Keep in mind older diesel systems were towards the higher end of direct injection gas engines. Water is the biggest problem with the newer diesels, while it can still be an issue with gas, no where near as much. Each system has different issues.

Of course the newer diesels also have all kinds of other issues from the new system to control emissions.