95 honda civic just installed a good used engine / mil light was not prior to replacement. I used the original intake to the vehicle and exhaust ( basically installed a long block with covers installed.) replaced timing belt and water pump and new axles as well. Engine runs very well... But the MIL light stays on all the time I have just replaced the negetive battery cables ( at battery post and at transmission ) checked connituity on the ground side under the hood all seems well. I think the problem is the ECU it's self just seems kind of odd before the engine was changed I did not have a check engine light and now I do ( Yes I disconnected the Battery before I replaced the engine. ) I thought that would be your first question. I anyone has an Idea or a test I can do to confirm anything pleas let me know - Mike.

Turning the ignition switch to ON (Position II), not START, does the CEL come on and then go off after 2 seconds? If not, the problem is with the ACG (ALT) (S) 15 amp fuse, in the under dash fuse/relay box; ECM; main relay; or the ignition switch. Perform tests in that order.

Nope , stays on until you go to the start position ( when all the light go out ) and you are cranking the engine over.Once started light returns. Srs light is on as well but it Extinguishes after a short while ( like normal operation ) only other lights that are on are : brake light ( parking brake engaged normal ops and selt belt light with seat belt not secured normal ops ) I have tried resetting it several times ( pulling back-up fuse disconnecting battery put it returns with no delay at all. Just got done rechecking all the grounds on the engine harness. Pinned out all the sensors to the large plugs on the shock towers and cleaned them as well. Was I correct about the sequence on the mil light ( when jumper is installed mil light will come on then Extinguish if the ecu has codes stored it will start flashing them after the Initial blink once ecu has reached the end of stored codes it will blink once more to verify his is the end on stored codes? I worked on hondas back in 91 to 98 I just can remember if that's the correct sequence or not thanks again - MIke

Turning the ignition switch to ON (Position II), not START, does the CEL come on and then go off after 2 seconds? If not, the problem is with the ACG (ALT) (S) 15 amp fuse, in the under dash fuse/relay box; ECM; main relay; or the ignition switch. Perform tests in that order.

Hello again checked the fuse it's good power on both sides. Also checked to see if alt was charging it is. I guess I need a ecu thanks for the help- Mike