530 Diesel can't start when it's between warm and cold
I really hope that some one here can help me, because the local BMW dealer and I are out of ideas now :-(
I have a diesel 530 from 2000 (M57, E39), and when the engine is cold then it starts whit no problems at all, and the engine sound nice as it should. When it is warm, it starts whitout any problems too. But when I have benne driving, and I leave it for 2½-3 hours and the temperature is between warm and cold, the engine runs but it doesn't start. Sometimes I just have to leave it for 10 minnutes other times for 1½ hours, and then it starts rigth away again.
We have updatede the software on the engine control unit, and there are no failure save at the computer.we have changed a lot but nothing works, soem of the parts is:
Diesel pump (the one under the driver seat), Diesel pump relay, DDE relay. the sensor at the crank, the heatglower. I have tried to take of a lot of plugs for the air control unit, normally it can start with out these plugs on, and with out them it will normally just go in emergency program and it should start anyway, but when I have the periodic fail it will not start.
Please help I'm desperate.