There are lots of things to try, but the easiest is to check for a good spark. Best way is to attach a good used spark plug to one of the wires, with the body of it touching ground (don't hold it!). See what you get while cranking. Also check condition of the inside of distributor cap and rotor.
If that seems ok, you could try limp mode by unplugging the OVP (or removing the fuse(s) on top). If it now runs, plug it back and unplug the EHA to see if lambda control is really haywire, und so weiter...