hard starting 300TD diesel

[foxpaws]

I have an '81 300td wagon suffering from all the aches and pains of its age, but still running strong. The biggest issue now is that it is hard starting, and I'm wondering if anyone can give me some tips on correcting the problem. My husband knows these engines inside and out, but isn't quite sure what's going on with this one. We have a new battery, I plug in the heater for several hours, and he's checked the glow plugs, air and fuel filters, and alternator. It just doesn't seem to get enough power to get the cold(but heater-warmed)motor turning. We end up having to hook up a charger or jump it every morning, then it will start the rest of the day. He has an old 240D with lousy compression that starts up on the coldest days without a heater, so I'm wondering why mine with a good motor has so much trouble. Recently the pre-glow indicator quit, though it is still pre-glowing, and the car has a long history of annoying electrical problems; fuses blowing, headlights burning out within days, etc. Any ideas out there? Thanks!