Daz3nt

Hi all, I have a 54 berlingo 1.9d, had the engine changed but needle lift sensor was missing from the injector on cylinder #1 and now the engine sounds like a bag of spanners. I've fitted a new injector complete with sensor and is now running fine for the first 5 seconds. After that the knocking noise comes back again. My question is do I have to reset the ecu for the changes to take affect? It's a Delphi fuel pump with Delphi injectors on a dw8b engine. Thanks in advance for your help.