Toyota Repair: 91 toyota 4 cyl [3SFE] no spark at plugs, angle sensors, toyota manual

Question
Ted, Thanks for the opportunity to share my problem. Several months ago I replaced the timing belt after it jumped several teeth. After several problems it started great after getting hot but was very hard to start when cold. I rechecked to see if all the timing marks were correct, they were. After driving it around, in/out of the shop/down the road it ran great.While try to find why it was hard to start cold it just stopped firing at the plugs. I checked the trouble codes, there was none activated. I have done all the checks the Toyota manual suggest, coil ,wires, cap,ect and still have no spark at the plugs. To date I have replaced the coil/distributor, new cap, new wires and 3 different igniters.I also got ECU from the salvage yard, still no spark at the plugs. With the ignition on I have voltage at + side of the coil and also at the igniter. Do you have any idea what could be wrong? what am I missing?  I have noticed that the "CHECK ENGINE LIGHT" doesn't come on now when the ignition is turned on. Hoping you can help, THANKS  

Answer
The only thing I can think of is that it could be a computer or injector ground wiring problem, recheck the ground connections on the intake manifold on the back near the firewall, check inside under both the kick panels, there are white/black ground connections, make sure they are clean and tight, check for continuity to ground at the computer connectors, all the brown/black wires are computer ground connections, check them with an ohm meter, there should no more than one ohm resistance from the computer to ground at those terminals. The computer also has to see a signal that the engine is turning at a certain rpm before providing spark and injection pulse, this information is provided by the cam angle and crank angle sensors, check the wiring for these sensors and make sure they didn't make contact with any rotating parts and were damaged.