I recently heard the 2014 Silverado's are DI engines. I thought they have been for many years? I have never got to see the head of a 5.3 LMG motor but does the fuel injector just inject the fuel after the intake valve opens and then the full is sucked in and when the intake valve closes for the combustion process the injector is sealed from the combustion chamber?

 

The fuel is injected while the intake valve is open. The air coming in prevents fuel from escaping through the ports. Compression takes over and the cylinder fires. This design is similar to a diesel engine. It creates more efficiency because no fuel is left in the intake monifold and this allows for higher compression ratios in the cylinder.

 

So the fuel is injected thru the hole that is created when the intake valve opens and when the intake valve is closed the fuel injector is protected from the combustion process. You say this is similar to diesels but I thought most were DI but engines like the IDI 7.3 diesel injected into a prechamber.

 

The injector sprays the fuel directly into the cylinder so the injector end is exposed to the heat of combustion. Newer injectors are design to handle this though, but as in diesel motors, you will find yourself replacing the injectors, but only after alot of miles, most liking when you reach 200+K miles

 

Could direct injection cause engine "tick tick" noise? (on a 5.3 L)

 

the di injectors will make a ticking noise...that is normal.

 

Great!!!...that's re-assuring.

Thanks!

 

it works at pressures 100x higher that a conventional injector. it will make some mechanical noise right from new. If you can design a quiet one, you would be a millionaire.

 

I'll think about it LOL!