on a 90??????? are you sure it isnt an 89, the sounds like an OBD0 ecu, the accords switched genereations in 90-93 where they are OBD1 where it flashed the code on the dash when you jump two pins, and this is how you find the clip to jump the wires.......on the passanger side, look UNDER the glove box to the right, and you will see a blue wire clip that is not hooked up to anything and blue tape holding it up, take off the tape and pull the clip down, and get speaker wire and strip both sides and put each side in each hole (2). DO ALL THAT WITH THE KEY OUT. then turn the key to the ON posisition and count the binks on the check engine light to check the code....long flash counts by ten, short flash counts by one example: --- --- --- - - the would be code 31 if there is such a code lol --- is long - is short for the example heres another one example: - - - - - - code 6 which is a coolant sensor issue and one more example: --- --- - - - - - code 25....hope this helped