body grounds and engine block

Just went over the star earthing points and body grounds. If I have the battery in the car and ground the negative of the battery to the chassis and then put a grounding strap from Chassis to block, wouldn't that be grounding the EFI to both chassis and block? the module says to never ground to both chassis and block.

No you are not.

With a Grounding Strap, you are allowing yourself the option of grounding an EFI component to ether the Chassis or Block.

It's bad to have a component, have both a ground wire going to the block AND a ground wire going to the chassis.

Just pick whatever is easiest.

You'r grounding the EFI system to the battery.

Not grounding the Battery to the car