How do I connect the SU FASD unit?
Here is a non scientific explanation of how the FASD unit works and also how to instal it.
The FASD works like an extra carburettor for controlling choke amounts/variation not only based on how cold the engine is but how much load it is under. In principal it monitors engine temperate to decide if and how much choke is required and it automatically enriches the minimum choke level when your vehicle is under load, i.e. accelerating or for up hill additional load.
This device has all the features of modern Fuel injected ECU controlled fuel enrichment but in its time was state of the Art Technology for carburetted cars, but because it is mostly still mechanical its service life was about 10 years and because few Rover technicians understood it it often got the blame for other engine faults and earned a reputation below its true ability.
||1 : Coolant device - Plumbed into the engines coolant system this device changes the fuelling (choke) level dependant on the coolant temperature.
2 : Vacuum port, this should be plumped to the engine intake manifold vacuum.
3 : Vacuum device - This receives engine intake vacuum from the filter housing or pipe leading to it and it increases choke amount under load.
4 : Electrical device - Fitted between the SU carb and the FASD this electrical device is activated by the FASD Drive Unit Relay.