what else to check before putting in new ecc

Make sure the computer power ground is connected and the area it
bolts to is clean & shiny. The computer has its own dedicated power
ground that comes off the ground pigtail on the battery ground wire.
Due to it's proximity to the battery, it may become corroded by acid
fumes from the battery. It is a black cylinder about 2 1/2" long
by 1" diameter with a black/lt green wire. You'll find it up next to
the starter solenoid where the wire goes into the wiring harness.


Picture courtesy timewarped1972

What about putting in a fuse on the computer power? If you are grounded out some where it might save you a new comp. I would check with jrichker first. This was just a suggestion. If you are worried about blowing the new computer. I would ask around before you go cutting wires. As I said before I am sure jrichker would be able to help out.

The stock alternator has a fuse link in the wiring on 86-93 cars. I suspect that your 84 is the same.

As for the ohms for a ground, the fewer ohms on a ground, the better it is working. Between the computer power ground and the negative terminal of the battery, you should see less than 1.5 ohms with the postive terminal of the battery disconnected. Disconnecting the battery positive terminal keeps the voltage drop across the wiring from affecting the ohmmeter readings. Just don't short the positive side of the battery to ground when you remove the cable. The results would definitely complicate your current problems.