hmm, I had problems with my ofab setup zvh too. To eliminate loom problems I went onto www.rsbible.co.uk > S2 > EFI Conversion. Scroll it down a fair way and you'll see two tables for ofac & ofab pinouts. I simply unplugged my main ecu connector and tested each loom connector for continuity.

Once I did have a prob with the injector loom part shorting out on a nearby sharp edge which stopped my injectors firing, maybe you've got something similar but check and you'll find out.

Good luck...