I just bought this truck 2001 GMC Cab and Chassis with a Cat 3126 in it. The owner said it didnt run and didnt know why.

I am heading down to look into seeing if I can get it running before I have it towed tomorrow and was wondering if anyone could point me in a direction with what to check and look for.
I am an auto mechanic so tools and know how I have but not much with diesels.

The owner said they put new batteries in the truck and it wouldnt start. But told me with starting fluid it would fire up and run fine. He said they ran it on starting fluid long enough to build 120psi in the brakes to release them. I know that was a big no no.

So im assuming it isnt getting fuel. Ide think running that long would bleed any air from it and if not how do you bleed the air in this motor, I dont think its a heat issue because after starting it should have ran on its own.

What should I look for and what to check first. Im hoping its a fuse os something stupid but who knows..

Thanks in Advance.