New ecu fitted - won't start (not immob)

[Andymac]

Me again... before i start the cae is a 1.8t aeb engine b5

I swapped my faulty ecu (hot start fault and error code: internal rom error) for a used one I bought, coded the immob and tried to start it, kept cranking but didn't wanna fire up and after 10 secs of cranking oil warning light came on, turned it off and tried again, this time I ignored the oil light and it tried to fire but was extremely lumpy and slow firing (300-500rpm) and there was a strong smell of fuel, also wouldn't keep itself going for long until it died.

Refit my old ecu and it ran absolutely fine (after burning off the excess fuel for about 10 secs)

The difference between the ecu's are the last letter, my original one being...
8D0 907 558 E
The new (used) one being...
8D0 907 558 S

My original ecu is chipped also so I'm wondering if that may be anything to do with it?

Car has a k04 turbo, bam injectors, induction kit, fmic, n75 delete and digital boost controller, decat and more than likely has a bigger fuel pump (maybe that's why I had a strong smell of fuel as standard ecu doesn't know pump is bigger?)

A couple of fault codes that cropped up were something to do with intake manifold flap I think and Camshaft timing adjustment bank 1 n205...?

Any help is appreciated, I think I'm gonna get hold of an ecu that matches my old ones code and see if it does the same, if it does I'll be fairly confident it is cos of the chip...