E30 Zone

I'll keep the details short and sweet

Car was a 318i now fitted a 2.5 twin vanos engine
Engine starts and runs
Throttle body was replaced with a good one because it threw up faults before
All fault codes cleared as was running in limp mode, ran fine for a bit
Idle control valve threw it in limp mode again
Replaced ICV and removed faults
Went in limp mode because of throttle body
Throttle body was replaced because it threw up faults before

It seems for some reason it keeps going in limp for issues that wouldn't usually cause it to? Engine was previously an auto and has had all the wiring done to change it over properly.

It's my mates car and he's about to burn the thing.

Is it possible the ecu is damaged?

If the ECU is from an auto car that will be your problem

+1.

The DME is trying to "speak" the the EGS which isn't there so is freaking out.

The ECU was changed from an auto to a Manual one. I don't think the engine was ran after the swap until the manual ECU was fitted.

I had an ECU fault recently on a 325i, MS42 ECU, diagnostics were saying "ECU faulty. throttle valve"
Engine would start but not rev and cut out in under a minute, ended up changing the ECU

Sounds similar, will not rev past 2500rpm and sometimes cuts out. If I could supply better information I would but it's my friends car... and he's looking to sell it for chips and I'm thinking of bagging a bargain if it's just a new ECU required !