Hi again - Jim - is it?
Ok from what you say - and I did assume this before - the vehicle was running before you did the job - so the problem is related -- When you say, the crank has to be at TDC -- what do you mean - for what operation? or are you thinking this is the case to time it up? If so, yes of course you are correct. But as you say, if there are no dowels etc on the flywheel then yes it can be fitted in any place - but something is not right there!
Thinking this through -- If the flywheel has a pin - or a gap - whatever triggers the sensor - and of course it will have something like that , then the flywheel will HAVE to be fitted in one position only! Usually there is a Cut Out on the flywheel that you line up with the new clutch etc ( sometimes on the clutch assembly, it looks like a 'teardrop' cut out --- and use that as your timing mark... Have you had a good look at all the old removed stuff to see if you can spot anything??
As I said just - It has to be the case --- Im afraid it looks like you are going to have to strip the lot off to check it - it must be on wrong Im afraid!!!! As you correctly say, the firing mech for the sensor has to be in the correct "time" - so HAS to fitted in one place only.
As I say, have alook at the old set up that you removed and see what you can spot.
Come back to me if you need more help - meanwhile I will look and see what I can find out for you further re the markings, but honestly, I think you may as well start pulling it to bits again - the flywheel is undoubtedly on wrong - in the wrong position :(
PLEASE press ACCEPT if you are happy with my advice given - Thank you. ;)