can someone tell me where exactly the TCU is on my 1991 Honda Accord LX. I have a new one that i need to replace but cant find where it is located.

 

It's under the carpet on the passenger side floor board.
Just pull the carpet back from under the dash and you will see a big metal plate.

It's held into place by four 10mm bolts
be carefull with the plugs they can be a pain