Have a 89 7.3 idi non turbo that will not start at all. Was running great got out and went into the bank for 5 minuets came out and started for 5 seconds and died and will not start. Tried a little ether and nothing. (Glow plug relay is bypassed and in working order) has done this before but usually will fire right up with ether. Any suggestions? Replaced all return line fuel lines all injectors are working. New batteries, new alternator, new starter. Any help appreciated.