i recently replaced the glow plugs, relay and battery in my 1981 300TD... before it was not starting, the relay light would not come on at all. Now the relay light comes on strong... when i try to start the car, it cranks and cranks... its tries to turn over but just cant... i made sure i had fuel and oil in the car. are there any suggestions? am i doing something wrong? Thanks for any help anyone could offer!