The timing procedure is to get the chain on the right tooth of the gear, If it's a hair off that's OK. Check the valves at TDC (use a stick in the spark plug hole) exhaust and make sure the exhaust has just closed and intake is just opening turning engine over bay hand in proper direction.
If compression is 140 to 150 with 4 strokes on all cylinders then compression is not the problem.

How are you doing with this??

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1988 325is (purchased new) sold
2004 X5 3.0 2005 X3 2.5
2008 X5 3.0 (new to me)