I'm not sold on that!

 

Its plain physics. Ether has a lower flash point than gasoline. But once some heat is introduced into the combustion chamber the fuel is easily ignitable. Another symptom is is will start if he makes short trips. and the truck does not have to sit long.

 

If you crank it for a long time does it fire up? My buddies '98 4.6l did the same thing as you describe, but if you cranked his a while it would start up. The cause was the fuel pump. It read good pressure on the gauge, but what was happening was it was allowing fuel to drain out of the lines, so it had to crank and crank to get primed back up. If it didn't sit very long it would fire up, but sitting overnight it would have to crank for about 20-30 seconds to fire up. New fuel pump cured that and it starts easily. I would say that yours is NOT ignition related because you would be having drivability issues if that were the case.

 

I agree with ether having a much lower flashpoint but if it's a spark issue, ether won't fire the cylinders without a spark unless the engine is hot enough to ignite the ether with compression (like a diesel). I really think fuel pressure should be verified again and followed by injector pulse test and spark test.

 

Starting fluid has a much lower concentration of either than the 80% either used to start a turbo diesel. The fact that introduction of starting fluid points to eather a weak spark/spark plug problem or an injection/start problem. Since there are no codes it's outside the CANBus monitored electronics. Maybe a collapsed pcv hose, something simple just overlooked so far. Look for the obvious, like a vacuum leak/hose off ect. Do comperssion tests and vacuum tests. Finding an out of caliber fuel system is high on my list of probables. Graph your PID's with a good code reader ASAP

 

BTW Plugs and wires were changed about a month ago, there is voltage to the crankshaft position sensor, but when i did the check of the sensor itself, I got NO voltage(AC) does the crankshaft position sensor start the injectors' first shot of fuel? also, what are these PID's?