ether is dangerous with glow plugs, but if you take the IC return pipe off at the intake manifold and give it a decent shot of ether it should fire. make sure to not "wait to start", turn the key directly from off to crank so they dont have time to get hot, otherwise you will get fire out of the intake. if the engine doesnt fire off of ether, you have a serious issue, likely valvetrain failure, and you will be taking the engine out.
i bet it will start on ether, and if it continues running that is good to know while tracking down the issue. like pete said, i would definitely post up in the 6.0 section.