I do it in conjunction with an injector
cleaning, cause I don’t have a way to decompress the
engine.
Removal of the injectors of course won’t allow any
compression.
Then I’ll use a plastic straw to determine TDC as my crankshaft timing marks are covered with a Serpentine belt kit.
But it’s easy find TDC of a cylinder using the straw as an indicator of piston placement and TDC is easy to determine because both valves are a little loose, if TDC
exhaust, they won’t be.
Now if you have indirect injection this isn’t likely to
work cause you can’t get to the piston tops.
If you use an indicator like a plastic straw, be sure to use something that can’t harm the piston, nor can be broken off.
Of course you can always download the engine manual and do it the right way, the procedure in the manual.