BMW E38 diesel stalls or won't start
Why does an E38 diesel stall under acceleration?
The most common cause is the fuel transfer pump or its filter, so the fuel pressure is not enough. The turbo has also been the cause. To narrow down the fault, a workshop tool can monitor the transfer pressure and the rail pressure while driving.
Why does an E38 diesel not start cold even though the starter cranks?
The cause can be a fuel pump that does not build pressure, a faulty transfer pressure sensor or broken glow plugs. A leaking injector lets air into the line, and then the engine has to be cranked for a while before it starts.
What do the transfer pressure sensor fault codes 1255 and 1260 mean?
Code 1255 indicates an electrical fault in the sensor, in which case the system uses a substitute value of 4 bar. Code 1260 means the transfer pressure deviates from the setpoint, which can reduce the injection quantity or stall the engine.
Why does the diesel not start after stalling even though the fault codes have been cleared?
Air has usually got into the fuel system, and it must be bled before the engine will start. Air can be drawn in, for example, on the suction side of the transfer pump, in which case filling the tank does not help.