My Z28 was running rough and fouling plugs after installing reman cast heads and timing chain, so I drove it into my garage and (after getting parts) put on new optispark, plugs and wires, new injectors, distributor, water pump, ICM, o2 sensors, new injector pigtails. It cranks great (new battery) but will not fire. Fuel pressure good a 42psi. testing revealed no spark from coil. What am I missing. Thanks for any help