I have a 1990 740 wagon 8valve non turbo w/ rex/regina system.
It died suddenly while running normally.
I traced the short to the wiring harness behind the alternator.
Three wires were crossed: the hot lead from the alternator, the small red one from the alternator (hence the battery light) and a green wire that I believe runs to the coolant temperature sensor. I repaired the cables.
Still no spark.
The crank sensor has been replaced and I have ruled out the fuel pump relay and the radio suppression relay. The Coil and power stage have been swaped out also.
The coil is receiving some power.
On board fuel injection diagnostics gives me 1-2-3 and 2-2-3.
Coolant temp sensor and idle air control valve. May have been stored from before.
It should get spark.
On board ignition diagnostics (position 6) gives no results.
Only a faint glow.
Could it be the Ignition control unit?
Where is it located? How can I diagnose for sure.
Wow!

Please Help

Richam