Am I missing something here? You said you shot a small amount of starting fluid in the air cleaner and it ran smooth for 3 to 4 seconds. Have you checked the fuel pressure with a gage. You should be reading 50 to 60 psi.
It's on my list of things to check, fuel pressure that is, just need time to. How often do the pumps fail and NOT throw fuel pressure codes?
Are the fuel pressure sensors typically faulty in this regard? I realize almost all sensors have been know to fail and not trip CEL, I'm just curious how common it is with Rams..
Also, this:
"Pulled the fuel supply line to injectors and cycled ignition to see if I was getting flow, it pumped what looked like a very strong volume into a bucket.
Obviously this isn't a performance test, but the volume should've been enough to start the engine at least. Hooked fuel lines back up and it still wouldn't start though."
It should try to start
a lot harder than it is, since the volume of fuel it produced, again not pressure/load test but still impressive stream observed, was a considerably higher volume fuel source than the 1/64 of an ounce of starting fluid.
In my mind, it should start up ok initially at least(like run for a few seconds), once the fuel pump gets some pressure built up early, and then promptly die off once the "possibly failing" pump cannot keep up with the demand; yet it's not even trying to start, but it will pump a lot of fuel into a bucket. Again, I realize the fuel it's moving could be too little to keep engine running for significant amount of time, but it's moving a decent enough volume to at least start up and run for the amount of time it did on the ether....
I hope this could be the cause, I just don't buy it yet.
Reallllly interesting the mech that looked at it couldn't talk to those modules he spoke about. I really wish he was a more thourough/modern individual, but alas. Would've been nice to get a detailed list of what he tried exactly and what he actually observed, but he was just doing a quick check to be nice, and I wasn't around.