EFI and VVTI what is the difference

Hello,

These are two different systems one is the way the camshafts work and the other is the fuel injection system.

EFI - Electronic fuel injection.

VVTI - Variable valve timing injection.

Here are two guides that will walk you through each system:

https://www.2carpros.com/articles/how-camshaft-variable-valve-timing-works

and

https://www.2carpros.com/articles/how-fuel-injection-systems-work

Please let us know if you need anything else to get the problem fixed.

Cheers, Ken