HDI Not Starting - Back Again!!

[Ruan]

That won't kill the ECU, it merely prevents power going to the lift pump, so if the lift pump runs, it's not that. What's very odd is that you say that the lift pump is running, but the EML isn't on?! If it's a power to the ECU problem, the double relay wouldn't power on, thus not powering the lift pump (unless your lift pump has been bodged to run via a different ign power source). If the ECU isn't happy about it's status (note: that doesn't mean the immobiliser is blocking start, that's checked at a much later stage and the ECU is booted and the EML will be on), it won't power on the double relay, the EML won't come on and the lift pump won't run - so something is a-miss here.