(Hopeful) Conclusion to my saga:
I went to fetch my Pajero back on the evening of the 7th of April. There were some delays in the process once the pump had arrived back; as CL diesel picked up a permanent error code 25 once the pump was fitted when doing diagnostics prior to starting the vehicle for the first time. The Pajero had to be sent back to Automax for the wiring & ECU to be checked again – 3 days. No fault found. Car was then sent back to CL diesel. CL diesel had a look at the pump and found the “timer piston position sensor” only had 2 wires coming out of it instead of 3. See Picture.

- Second hand unit fitted on pump in engine bay.

- Second hand unit - as fitted to pump?

- Second hand unit - sent back with pump?
I had a bit of a fight with Randburg diesel about where the calibration certificate was (it was not supplied) and why they fitted a second hand part to my Pajero when I paid for a new one. Eventually they decided to send down a new on which was fitted in-situ with the pump on the engine by CL diesel. They did diagnostics again and then started the engine and now she is running beautifully, only problem was the SRS light stays illuminated (error code 12 & 13) and the outside temperature sensor wasn’t working on the on-board display screen (and therefore my climate control didn’t work either).
I found a large 38 pin junction plug (D28) where all 6 sensor wires (4 for SRS airbag sensors & 2 for ambient temp) go through to the engine bay from the cabin – behind the front passenger kick-plate.

- D-28 plug connector (4-7 = SRS & 21-22 = Ambient Temp)

- D28 in cabin
I knew that the wiring had been given a once over so I reseated the plug and the ambient temperature gauge worked again, but the SRS light remained lit. I tested the front airbag sensor pins (4, 5, 6, 7) at this junction and they came in at 0.820 kilo-Ohm or 820 Ohm – so both sensors are spot on. I need to still look at the SRS-ECU and see if that was also damaged, or if that plug was disturbed as well during fault finding.
My conclusion to what caused the issue:
GE actuator - catastrophic failure of ROM module.
I asked for my old parts back from Randburg diesel; they sent back the GE actuator, a timer piston pin, and a timer piston position sensor (also a second hand unit – not mine) as quoted on invoice for replacement. I was always of the opinion that the black ROM module attached to the side of the GE actuator was at fault, as I mentioned earlier in this thread on smelling burnt wiring on my fingers after handling the unit. I removed it and decided to open it up for further inspection. The whole unit was fried – seriously burnt on the inside, even some of the wires had melted inside the lead, and one even burnt completely* off. I reckon that the GE unit itself is 100%, if you could obtain a new ROM module you could re-attach/resolder it to the pins inside the actuator and use it again.

- GE actuator unit with ROM module(on side)

- ROM unit - pin burnt out

- Sheath burnt out

- Wires melted

- ROM unit - fried
As far as I can see the mechanical side of the GE actuator has a stepper motor of sorts inside which manually rotates a shaft. This in-turn causes more diesel to be injected into the motor to accelerate the engine. It also has a a fuel temp sensor underneath which is always bathed in diesel fuel inside the pump.
I must say I am a happy chappie right now at having my van back, Pedro is running sweetly (and not as noisy anymore) and has more mid-range grunt.
I must just add, hats off to Rassie at CL Diesel & Gerard at Automax for sorting out all the gremlins and their utter professionalism shown in sorting my strange issues with my Pajero - definitely a thumbs up for their service.[/font]