Got a problem starting my '87 300D Turbo sedan this AM. My wife said she was driving with the reserve fuel light on for a while last night so I thought she just ran out of diesel but this AM, after dumping 5 gal in, it still won't start.

Good battery power, the starter seems to be audibly worked strong, the glow plug light turns off in the usual amount of time, but I just can't get it to crank over.

I'm wondering if it is the fuel pump? Or maybe a clogged fuel filter....I'll replace the fuel filters next but how do I troubleshoot the fuel pump?

Other ideas? Can't think of whatelse it might be, although I'll probably check the glow plugs as well.

Thanks -Harv