My son has a 1988 Honda Civic Wagon that I am helping him trouble shoot and need some help.

He was driving on the freeway the other day and the gauges pegged and the car stopped running. When they pulled over the battery had boiled over and the car would not turn over. Had the alternator tested and it was putting out 27 volts. Changes the alternator and battery but now the car will not start and has no spark. We changed the main relay and coil with used parts from pick and pull. Working on trouble shooting the problem we found that the check engine light stays on but the LED on the computer does not blink. As far as I can tell we don't need to jump any wire or anything it should just blink when there is a check engine light on? So we picked up used ECU and same thing check engine light stays on but no blinks from the LED.

Is there something we are missing that needs to be done to get the LED light flashing?

What would be the next logical thing to do to make sure the ECU is in working order.