Let's go over how to install a chip or other electronics into EEC.
Disconnect the main connector with a 10mm socket, and remove the EEC from the vehicle. Now take the EEC somewhere safe to work on it, I would suggest the kitchen table. Because this has to be careful clean work, if your getting too messy for the kitchen table you need to slow down and be more careful. I’m installing a TwEECer below.

After removing the ECU from the vehicle, remove the top and bottom cover, exposing the circuit board. You can now clearly see the J3 port. The J3 test port was intended for last minute testing in the factory, and then it was sealed, never to be used again. But this port is the best way to enhance the programming.

With this in mind we have to clean the J3 to use it again. It is imperative that you clean these contacts, if there isn’t good contact in this area, you will have problems. Use a swab to wipe off the excess protective grease, and then scrape off the solder mask (usually green in color.) Super fine sandpaper, steal wool, scotchbrite pad, pencil erasers, and small screwdrivers will work. Make sure you clean both sides, there should be 15 contacts on each side. Wipe the connectors with an alcohol pad to remove any dirt after using the scotchbrite pad. Visually inspect the surface for any residue on the contacts, one good tip is to look at the connector with a light shining on it, any spot that does not reflect the light needs to be recleaned.

DO NOT USE EXCESSIVE FORCE WHEN SCRUBBING THE J3 CONNECTION! THIS WILL MAKE THE CONTACTS TOO THIN, THUS CAUSING THE CHIP MODULE TO HAVE POOR CONNECTION.

Now you can close up the EEC. Some of the higher end models like the TwEECer contain more than one program will have cables to be routed from the computer. Route this harness safely to the switch. This switch allows the driver to pick different programming data that operates the engine. Use a smallpiece of tape to seal the computer from any dust. I used a small piece of foam to fill the void between the chip and computer, then my non-stick harness wrap.

DO NOT USE EXCESSIVE TAPE TO SEAL THE COMPUTER. TOO MUCH TAPE WILL CAUSE THE COMPTUER TO OVERHEAT!

Reinstall the computer back in the vehicle.