You haven't mentioned whether you have a fuel hand priming pump, or not.
If you do; Did you pump up the fuel system, before you tried adding ether to the engine.(if there is a lot of air in the fuel system ,then there is not guarantee that ether will get it running)



OK, if you had the OEM plug(rear plug) off of the CAT ECM, then here are a couple important measurements.


Pin 70 = "keyswitch ON" pin = with key on, should have battery voltage{+}(also use a test light, too=does it stay bright?)

Pin 63 and 65 and 67 are battery negative pins{-} [there should be almost no resistance to battery grd(measuring all the way back to the battery negative post) = close to 0.00 ohms]

Pins 48 and 52 and 53 are unswitched battery positive pins{+} and should have close to or equal to battery voltage, BUT here is the kicker, WITH the plug unhooked you aren't pulling any amps, so you could have a very poor connection or corroded connection and your voltmeter may say it is acceptable, but it may not be(applies to pin 70 also).

Hopefully, you have a test light and you can touch it to those pins and see if the light dims out, BUT test lights don't pull very much either.
At Work, I use a 12 volt DC spotlight, out of my 4x4 pickup, to test that circuit and the voltage drop is only around .2 to .5 volts DC.

If you have an old or new car headlight/lamp laying around, you could "jerry-rig" it up to test, too. A very poor circuit, won't even light the lamp.

Now, test;
70 to 63 (with key ON)
70 to 65 (with key ON)
70 to 67 (with key ON)

63 to 48
63 to 52
63 to 53

65 to 48
65 to 52
65 to 53

67 to 48
67 to 52
67 to 53

I do all these with my voltmeter and test light, first, because a serious problem will slow up quickly;  then if needed I get my spotlight(to pull more amps).CAT will teach you to install "test spoons" and leave the 70 pin ECM plug installed into the ECM= I know you don't have these "test spoons" so I am giving you an alternative.

If you see a problem, then start going from battery grd (from actual battery negative post) to pins 70 or 52 or 53, to help isolate the problem area) If good voltage/good light appeared; then in this senerio/check would be poor grounds .


EDIT: I looked up your serial number and there is two additional pins to check
 (pins 48 = + )and also (pin 63 = neg)