Just did the head gaskets and myriad other work on the father in law's 2004 T4R. Not a familiar vehicle for me to work on but I've done head jobs on 80's BMW's 1997 Jeep 4.0 and my mother's 1997 BMW 328i.

I'm intimately familiar with the need to have the timing set right when reinstalling the timing chain which might I add was a bit of a ***** to get installed with the colored links on the marked teeth on the cam sprox.

AFAIK the mechanical timing set was good to go and i buttoned her up.

It starts but it's not an easy start and it stumbles for a bit with the occasional backfire and then idles well, but won't rev and i'm getting the codes for the crank/cam miscompare p0018 and both Oil control valves p0010 and p0020.

I'm assuming one of the two types of codes is correct and throwing the others.

I'm digging back into the valve covers tomorrow to verify timing marks all still line up.

The oil control valves themselves were clean and Ohm'd out to ~8ohms.

I'll check the filter screens for the OCV's tomorrow while i'm in there.

Any suggestions are welcome.

I broke one of those sensors on removal, and have a cheap part on one side and it works fine.
My HG project went together with no codes upon startup, which is the scariest part and it ran smooth. I was for sure to turn it over 5 or 6 times to make sure all marks lined up on the cams. Hopefully you aren't off a tooth!

It sure feels like it's probably gotten off a tooth. I turned her over and got no resistance at all so thankfully no valve to piston action but i'm suspecting there's a tooth or two skippage at this point. Almost the only thing it can be. It's just another day under the hood... FFS.....

I agree it's almost got to be out a tooth or two. That's the only thing that really makes sense. I've found through my 30 some years as an auto tech that if it's doing something like this after the repair that it wasn't before it's usually gonna be your own fault. Talking about myself, not you.

So after resetting all the timing marks correctly, on firing it up again it sounded like a little man with a hammer in the valve train...

Strangely this was NOT occurring when it RAN with the bad timing setting. I checked the cylinders for any marking on the pistons with a bore scope and find no marks on the pistons and so far 1,2,4,6 are making compression. I had to stop testing when the passenger side oil passage shot oil all over the garage wall. I don't have the means to leak test but i would expect this level of KNACK KNACK KNACKing to be a bent valve with evidence of impacting the piston face and VERY low compression if any.

I'm at my wit's end. My father in law is going to disown me and bury me in a shallow grave if i can't get it running.

my only possible clue is when i was resetting the timing marks the tensioner was off and the chain slipped several teeth causing me to have to blindly hunt my way back to a safe TDC condition for both banks and the crank by alternating turning the crank and then the cams to get back to TDC condition on all 3 locations. At one point i did feel resistance that I figure was mechanical interference. Possibly slightly bent a valve with the light contact?
Maybe this contact didnt' leave a mark to be seen with the bore scope?

I still am mystified by the compression on the cyl's tho granted i haven't gotten to 3 and 5 yet....