i have a manual and the wiring diagram is the most confusing thing to look at, are you sure the tacho wires to the alternator or are you like most people i have spoken to just presuming many diesel engines do not have a pickup for the tacho on the alternator and use a sensor on the injection pump or flywheel housing, i am not trying to fit an aftermarket tacho but rather trying to identify some additional wires on the fuel pump (bosch ve) this is because i have a power problem and the first thing to investigate with a turbo engine of this type would be turbo boost and fuel pump set up before delving deeper, as i have wires that i cannot identify, then these may be causing the problem and identifying them would be priority, all the manuals i have come across have been for much later versions of this engine, i have even been to the main dealer and browsed through their manuals but even they did not have a manual going back this far so as a last resort i post on this site and get some smart arse suggest i read the manual, plus i dont own a fourtrak just the engine in a landrover defender so most of the manual is errelevant.... thanks for trying to help.......