that is the engine check light telling u to check the error codes.
usually with a 1G conversion there will be something thats not needed or not hooked up, eg. air con, or speed signal from auto gearbox etc. if EVERYTHING was hooked up then there is a possible problem with some part of the engine.
there should be a little black box in your engine bay marked (if i recall correctly) 'diagnosis' u have to jumper 2 terminals and then the little light will flash u a code in a sequence of flashes.
check out this section for engine manuals, the 7M and 4A have similar error code tables.
EDIT: i disconnected my engine check light as my air con isnt hooked up and it stays on all the time. Now each time i service the car i check the error codes then disconnect the light again.