Toyota Repair: O sensor trouble, now camry will not start., toyota camry v6, 1990 toyota camry

Question
Mr. Ritter,
My friend did an exhaust valve job on my 1990 Toyota Camry v6 2.5(Is this your favorite Toyota to work on?). He returned it to me running perfectly except the ck engine light was on and the car would not pass emissions. I got a code 21(oxy sensor malfunction) and checked the sensor. All four wires on the pigtail of the sensor pulled out of the connector. I replaced the wires back in the connector even though I was not sure of the proper order.(I talked myself into thinking they were passive,What a dummy.) I tried to start the car. It would turn over and not start. Seems to be getting no gas. I disconnect the Oxy sensor and still no starting. I believe I checked all the fuses that I know for the ECU and they were good.
    Could you please tell me the order you would go about troubleshooting this problem? Is there a mystery fuse somewhere or should I just go buy a new ECU? I appreciate the great service you provide on this site.
Thank you,
Bob  

Answer
Have you checked the EFI fuse under the hood in the fuse panel? It's possible that this fuse blew out because of the incorrect wiring, disconnect the O2 sensor from the wire harness, the O2 sensor will not cause the engine not to start it is strictly an emission control device, replace the fuse and see if it starts up. If this is not the case get back to me and let me know what happened.