HDI Not Starting - Back Again!!

[8v_chris]

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.

Well the lift pump buzzes for maybe 3/4 seconds then cuts out, when the ignition is turned on so its priming. you can even feel it if you put your hand lightly onto the seat but at this stage the back seat is up and the lift pump exposed. If the key is turned further as though to start the car i cant hear if its continuing to run because of the noise of the engine turning over. Is it possible that the fault lies with the double relay? Its sending the signal to run the pump but then something isnt running back to the ecu, or perhaps theres an inline fuse somewhere, fuse in the fuse box i've missed?

As far as i can see, theres no odd wiring, bodging or general poor workmanship on anything, or not as far as i can see anyways. the only thing potentially dodgy is the ecu wiring has no cover over it, leaving the plugs more or less exposed. also, after looking round things earlier, i suspect the engine has been jetwashed/steam cleaned prior to MOT. I'm betting its the source of the issue, or the thing thats triggered the problem anyways. Water has got in, damaged the ECU and now its corrupt.

For clarity, this is what I'm seeing when i turn the ignition on. this is the second i turn the key. the glow plugs only run for a second at most. no EML -