I have transplanted the engine from 1990 STD Hatch to another chassis of the same vintage and trim. Tried to start the engine and there was not fuel coming to the engine. Power is coming to the pump but the pump was not pumping. So the fuel pump was transplanted to new home, thanks to my son, and is working fine. I have fuel coming in to the engine. Now, I thought the engine would start but didn't.

The plugs are not firing. I had newer looking but un-known-to-me distributor installed initially, it was in the back of donor car. Swapped it with known working distributor from old car, but still no spark. Battery voltage is coming to the coil. There are continuity to crank and TDC sensors.

Weird thing is that CEL light is "on" in dash but it's like half lit,,,,. Not bright. And stays on. Red LED on ECU stays on, too. The ECU is from old car which was working when parked for this project. The incoming voltage to ECU terminals (A15 and A13) was measured and it is like 1.5V as my son said. Looking at the diagram and I think it has to be battery voltage. This voltage is supplied via "Main Relay".

Now, would this low voltage to ECU condition causes for lights to be on and stay on? And causes not to spark? What is required voltage to ECU at the terminal, A15 & 13?

 

Check the ECU ground wires on the thermostat. It's easy to forget those when swapping the engine.

 

Sure enough, that was it.

The thermostat was replaced while engine was out. The bolts were tightened to finalize the installation and then engine harness was routed. I over looked that tiny bugger/ground when I did that.

Thank you, mk378.