Hello again.
The bloke has been to a diesel specalist who reckons that its
something to do with the advance & retard, but hes also been told that the problem is with the sensor on No 1 injector which can throw up the same fault, the engine runs great and tows his caravan as normal, its just that the emu light is lit but in fact sometime goes off when it wants, has anyone come across this before,
its a bit of a poser!!!