I'm getting no spark from my 1990 740 turbo wagon. It's been suggested that I check the pick up coil in the distributor, but I have confirmed that the '90 740 has no such part. I've now been pointed in the direction of the reference sensor. Would a bad reference sensor equal no spark? I've gone over the power stage, ignition control unit, ignition coil, cap, cables, rotor and plugs...all check out good. I'm also getting good fuel flow into the injector housing. Any ideas or suggestions would be greatly appreciated!

 

Yes that could cause a no spark condition from my understanding. You seem to have checked out the rest. Remember that you can have fuel pressure but none in the engine if the injectors are not pulsing (radio suppression relay) usually on the coolant bottle but I have no idea where it is on a turbo or even if they HAVE one. Use logic probe or i have heard you can use an inductive pickup timing light to check. Now how do you get that big old clamp on that tiny little wire? Logic probes are relatively cheap and i think cool.