E36 320i Engine Rebuild Problem

[JBSAFC1973]

Hello All,

I would be grateful for any info you can offer about problems I am having after an engine rebuild.

I bought a 1996 320i touring with a bent rod after it ingested a slug of water. It has a M52 Single Vanos Engine - I have replaced all the con rods and big ends, and I rebuilt the engine back up. I timed the engine using the correct tools (i.e pin at TDC and blocks over back of cams) and replaced the VANOS as per instructions in the TIS (catching the first spline and rotating backwards etc)

The crankcase breather was clogged with sludge going up to the cyclone, so that was all cleaned before replacing. I made a slight error in assuming (assumption being the mother of all cock ups!) that the fuel feed would be the bottom rail and the return would be the top - when trying to start it I noticed that fuel was pouring from the fuel regulator - so I switched them around and bingo it starts

BUT..
When it starts, there is a very slight back fire when you rev it, and it feels as though there is a slight hesitation when blipping the throttle.
When the oil filler cap is removed the engine starts to die, and it can only remain off for a few seconds before it will cut out
When the dipstick is out there is a significant gurgling noise from that area, again affect the engine speed but not as bad as the oil filler cap.

So, ... My questions would be
Does it sound like I have the timing incorrect? As I say I used the tools but had to guess the exhaust camshaft sprocket position as straight up and down as there are no references for the arrows on the head
It is possible to use OBD Live data to confirm the timing - I have the connector/software and the car has live data enabled OBD - what values would I be looking for?
Is it possible it is a vaccum leak? - Is there an easy way to check - possibly using live data?
Is it possible I have damaged the fuel pressure regulator by putting the flow in the wrong direction?

There are no DME fault codes being highlighted.

Any advice would be gratefully accepted. Thanks in advance ( or retard ;o)
Best regards
Julian

[Jeron]

The oil cap and dip stick tests indicate vacuum problem. Normally those tests would indicate a bad Cyclone Separator.