I'm going to try this again. After installing a new temp coolant sensor and reassembling the intake mainifold, etc., I now have no fire at the plugs. I checked voltage at pin no.6 on the ECU connector and have no voltage there.
I don't see anything in the wiring diagrams between the ignition switch and the ECU, which suggests no fire coming from the switch itself. However, all gauges and lights work when the key is on and I have 12 volts at the coil. Seems to me unlikely that the ignition switch failed while the car was sitting still and the negative ground off the battery.

I'm stymied. Is there an easy way to bypass the ignition switch to see if it is really the problem? Or can anyone suggest something else?

 

Have you checked all the fuses including the large one on the drivers fender near the battery ? I think that one is for the fuel system ecm.

 

the ECU has nothing to do with spark, its just the fuel injection controller. spark is managed by the ICU.

as busdude2 says, the 25A fuse near the battery is the main power for the fuel injection system, including the fuel pumps, the ECU, injectors, etc.

the fuel pump relay is in this circuit, too. its actually a dual relay. one half of it powers the ECU (when the ignition is turned on), and the other half powers the fuel pumps (when the engine is turning over as sensed by the CPS [crankshaft position sensor]).

ECU pin 6 is a signal wire to the AMM/MAF (airmass meter)

at the ECU, pin 35 is power from the ignition switch, pin 4 is always-on power, and pin 9 is the main ECU power via the aforementioned relay.