OK if there' s power to the regulator the next step is to measure feul pressure at the fuel distribution n unit
any fuel injection shop should be able to cope with this as the fuel pressure when the engine is cold should be 6.5 Bar when cold and drops to 4.7-5.2 bar with a warm engine
if its not this high then I'd suggest stripping the regulator down and cleaning it
The regulator is held to the engine by two hex bolts, and is held together by four flat-head-screwdriver bolts. Be careful! The unit contains several springs and other fragile components. Take it apart indoors in a clean environment where you can keep track of all the little pieces. When it comes apart, there are three metal pieces held together by two gaskets in a sort of sandwich. If your gaskets are ruined (hopefully not) you can replace them with that gasket maker stuff.
Once you have it apart into these pieces, you’ll need to remove the 10mm nut on the heating element and carefully bend the heating element out of the way by bending the two wires that attach to it. Now, use a small flathead screwdriver and remove the four bolts that hold down a circular diaphragm.
Once you have that taken apart, get out your carb cleaner and spray out the insides of the thing as best you can. Now, put it back together, making sure that everything goes back the same way it did before.