If your sure its got good fuel (spaying starting fluid in intake easy test), its getting spark all the time and your timing is still good, should run. You could pull off the right (driver side) plastic cam sprocket cover and turn the crank clockwise to TDC to check the timing.

For the ECU you can check it with an analog meter as described HERE and in the factory service manual available at Mitsubishilinks
I believe the picture on the first link under "Cracking the code" and the pic in the FSM show where to put the meters leads looking at the back of the test plug where the wires are going into it. Also the test plug was moved on my 90 to under the glove box rather then behind it as shown for the 89. Likely the same for your 91.