I don't see that fogging will have anything to do with the pressure
regulator. And at most it will sit on the outside of the injectors. I
would not have any problem fogging an efi engine. The main point of
fogging is to get some oil in the cylinders for storage. You can also
remove the plugs, squirt a little oil in each cycliner, crank it over a
few times, and then put the plugs back in.