I have been working on my '79 300td and dont know what next to do. Ive had a lot of problems with it being hard to start esp. in cold weather so i borrowed a DMM and found my #3 Glow Plug was out, this is the series filament type so #3-#1 were all out. Replaced all GP's and rather than fixing it it seems to have made it worse. Where it once coughed and sputtered and if lucky stumbled into starting it now just cranks and cranks with only the occasional cough. I have run my battery down trying to start this thing and recharged it numerous times. I pluged in the block heater for 45 minutes before trying again and ran the plugs twice, nothing. I thought then to do a valve adjustment which did not help. Then i thought it was my battery/starter being weak so i charged up, and used my charger on the jumper 50amp setting to try and boost it's cranking speed. Still did not start.

What should i do? I know i did not properly ream out the plug holes for lack of tools. Would this make all the difference? I dont have the DMM right now so i can not be sure but the connector wires all get hot so i am assuming the plugs are all getting power. I have thought about replacing the battery and the starter but i dont want to just dump money in the wrong place. maybe its not the wrong place though, considering how hard i have been on the two. I thought of doing a compression test but i dont have a compression tester or know anyone who does... i really have been looking this site up and down and im sorry to make another thread but i dont know where else to go.