Fuel Injection ECU - opening the box           

I originally, mistakenly, said that way too much had to be undone to get into the box.  All that has to be undone to get to the business section of the circuit board is the metal crimp tabs that hold the top cover on.  The screws and snap clips hold the board onto the base plate, and these do not have to be removed to gain access to the top of the board (and the PROM).  

If you're going in, be sensitive to the need to suppress static charge:

• Strive for a static-free work environment
  • Preferably not on carpet
    • A concrete floor or driveway is good
• Near a water pipe or some other source of ground
  • Not necessary if working on concrete
• Don't be walking around scuffing your feet and building up a charge
  • Touch electrical ground before handling the circuit board
  • As much as possible, handle the board by its edges

   

• Undo the crimp tabs
• Remove the cover
• Et VOILA! (or, as we Tennesseeans say, "Hey ya'll, lookit here!")

Reassembly

• Make sure everything is right with the board
  • No bent PROM pins
  • PROM retaining clip installed
• Re-install the cover onto the front plate/connector assembly
  • A bit of silicone spray or dielectric grease on the rubber seal is a good idea, and makes assembly easier
• Fold the crimp tabs over
• It's ready to re-install