Plugs changed, dizzy cap checked, sparks are fine. Stepper motor removed, cleaned and seems fine. Fuel pump checked & seems fine. Fuel pressure at the fuel rail. Coolant temperature sensor resistance checked & seems fine. Lambda sensors recently changed & seems OK.
When the car is running it runs perfectly on petrol or LPG. If warm will restart immediately, this with timing set using a strobe at 6 degrees BTDC.
If engine is cold (next morning) refuses to start, just gives an odd cough. However if I turn the dizzy anti clockwise it starts after about 3 turns of the starter motor, then revs to about 2k & falls back to 750 ish. Turning the dizzy clockwise to the 6 BTDC position with engine running is no problem, apart from large fan trying to chop fingers off. From then on car runs perfectly .... until next morning when won't start again !
Anybody any idea of where to look for the problem?
I am thinking maybe ECM problem or maybe fuel pressure regulator ?
Any ideas gratefully received.