Need to make CHECK ENGINE LIGHT come on briefly upon initial start-up to pass smog.

For some reason, my yellow "check engine" light is not flashing for several seconds upon start-up the way it should be, along with all the other major warning lights. I have been told by my local smog man that this alone will cause an instant "fail" for the smog test here in L.A. Any other time that I am driving the car, the light has come on a few brief times upon heavy highway acceleration, but then would go out shortly afterwards. Therefore, I know the bulb itself is good and does not "need to be replaced" as the smog guy is suggesting. Also, I checked the ecu down on the passeger's floorboard for any trouble codes, and no blinking lights whatsoever, and I am doing this the whole time with the ignition in the "on" position. Getting back to the check engine light not flashing upon start-up with all the other warning lights: What would cause this?