6.5 turbodiesel not starting
 

So I have a 1997 gmc 6.5 turbo diesel and my problem is that I go to crank it but it will not fire although it will start to smoke out the tailpipe so it's getting fuel at least some. It will continue to crank until I kill the batterys and not once it will fire. Now if i shoot a little ether it has no problem starting and will continue to run with no problems at all. Ive Ran it for a full hour with no problem in park and drive it for almost an hour. Also when I bought the truck (like 3 months ago)it would do the same thing the guy said he had got cheap batterys but the truck jumped with another diesel truck and I drive it home. So i have 2 new batterys new fuel filter put in. Could it be glow plugs? Oh and I've add seafoam to the gas and ran it for an hour hoping it would clean the injectors. Help plz!