Tuning chip problem, help needed!

[Andymac]

Car is a 99 b5 1.8t with k04 upgrade and bam injectors amongst other upgrades.

Been having a hot start issue for a while (changed cts and crank sensor) so I assumed it was the ecu (also got rom error fault code).

My ecu is chipped as it's too old to be mapped by obd so the new (used) ecu I got was sent off to have a socket soldered on.

I got the new ecu back and put my tuning chip in and it won't start, no immobiliser light and vcds won't contact the engine controller, the standard chip that was originally soldered to the ecu works in the socket but obviously the car runs like poo due to the upgrades and uses way too much fuel. (obvioisly we coded the new ecu to the immobiliser). With the standard chip in, the dashboard lights (immob, airbag etc) stay on for about 3 seconds and go off, with the tuning chip in the dash lights go off after about half a second.

I've tried all sorts and also been round every point on the chip and socket with a multimeter to make sure there is a connection and they all had continuity.

Can anyone shed any light on this? Is it something to do with the chip needing coding to the new ecu or anything? I've ploughed a lot of time and money into this fault and I'm at the end of my tether.