As you are not a member, I have copied over the self diagnostic article for Z31 ECU for you. Run the test and it may direct you to the failed input signal...
The two most likely causes of sudden failure in the Z31 are air flow meter (air mass sensor) and crank angle sensor (which is an integral part of the distributor).
The ECU has a self-diagnostic mode which will allow you to read fault codes for major sensors.
Unhook the ECU from its bracket in the left of the passenger footwell (but leave it plugged into the ECU loom) and locate the mode selector (a small screw on one side).
Turn the ignition on - LED lamps viewed through the side window alongside the selector screw should be on.
Turn screw clockwise and LEDs will flash - red LED counts "tens", green LED counts "ones", e.g. one red flash followed by three green flashes = code 13.
Write down the codes displayed (they will recycle, so don't worry if you miss one).
Depress and release accelerator pedal.
Shift transmission selector through each gear in turn, return to neutral.
Start engine (if possible).
Drive forwards at at least 6mph.
Turn air-con on and off (if fitted).
If all is well (and you have air-con that works!) then code 44 will be displayed. If all is well and you do not have air-con, then 31 will be displayed.
Any other codes should be covered by the following list and, if still displayed, indicate a fault in that system:
Code 11 : crank angle sensor
Code 12: air flow meter
Code 13: cylinder head temperature sensor
Code 14: vehicle speed sensor (turbo models)
Code 21: ignition signal (coil and/or power transistor)
Code 23: throttle valve switch
Code 24: neutral / park switch
Code 31: air-con malfunction (or no air-con fitted!)
Code 32: starter signal
Code 34: detonation sensor (turbo models)
Sometimes the faults are in the harness or the plugs - check for corrosion, broken connections etc. Anything been disturbed recently??
If this is all clear, then consider fuel pressure problems generated by pump malfunction or control module malfunction or pressure regulator malfunction.
Don't forget the obvious things like ignition / coil lead shorting on metal part sof engine, clogged fuel filter, bad plugs, low battery voltage....