new here,won't start unless plugged in

[valleyrat]

I tried searching this forum before posting such common problem but it kept saying nothing was found. batteries are almost new, no codes showing, all fuses check good, new air filter, new fuel filter. Before I pull my valve covers to check the glow plugs is there anything else to check first?

[NoRalPh]

You've got a typical Glow Plug issue, before you do anything else goto the Stick above and follow the GP TEST procedure..