Motor diesel b2500

I would be checking the stop- solenoid on the pump if you have one . next check for air in the system and bleed it all out.

This will almost certainly be the plastic fuel pipes connected to the fuel pump replace both of them this is a common fault the rubber o rings on the pipes harden and leak make sure you prime the diesel filter after replacing these pipes the engine can be difficult to start on this model once air is allowed in the system

Diesel ?? common rail or injector pump ,either way firstly i would suspect the head gasket as it sounds like its burnt through between cylinders one and two .This is the most connon fault with any engine

I would have the injection pump tested for porper function. Since we do not have diesel BMW's in the USA that is about all I can suggest. Sorry

What is this, Mazda's do not have diesels in the USA anymore.

which is the model?

garages are not diesel specialists
take it to a diesel specialist repair shop for a proper diagnosis

usual problem ,valves in injector worn for the fuel pump.easy quick fix this one ,fit a non return valve in the inlet pipe,check flow direction on valve when fitting and evan better as well is another in the bleed off return pipe .valves available from a motor factor or a specialist garage like bosch or lucas ,cut pipe and fit the valve with a piece of rubber pipe to connect the valve in line.or listen to the people who want to milk the golden cow and have the whole injector pump overhauled .

Undo the fuel inlet Banjo bolt and carefully fish with a piece of wire bent at the end (as pictured) and fish out the filter (under the spring) wash and replace. Can be very fiddly, so patience is a must.

It will get to the point it will not start. You have a bad o ring on the high pressurs oil pump sensor Ford has a kit for the fix