Replaced ECU - fuel gauge not working - still no start

Hi all,

Chevrolet Aveo (kalos in UK) 2008, 1.4 petrol.

So, briefly after the battery dying I jumped the car with the key in which I think causes some issues and the car booted the key from the ecu/immobiliser. Then it would crank but not start at the immo light just flashed.

So, after some reading I found that if I replaced the ECU, the key cylinder and the immo ring (around the cyclinder) it would work. So I bought from a scrap yard the three parts from the same (working they said car).

I replace all the parts, now the immo light has stopped flashing but the car still cranks no start.

Now this is the situation....

-I can't read the new immo, it always says failed to connect (the old one read fine)
- The fuel guage does no move when the ignition turned on ( I know there is at least a quarter of a tank).
- I can not hear the fuel pump priming when I turn the key to on (I could with the previous ecu and parts).


Has anyone got any ideas why the new ecu and parts seemed to have cured the immo flashing problem but now has caused the other issues?

Hoping someone can offer some advice,

Many thanks!

Al,