BMW E34 525tds injection pump leak and injector faults
Where does the E34 525tds injection pump diesel leak come from and how is it fixed?
The leak usually comes from between the pump covers, for example from the lowest cover or the injector line side. You can replace the cover gaskets yourself with a gasket set. Diesel smells, so the leak is easy to notice.
How do I replace the pump's intermediate cover gasket without ruining the pump timing?
The cover position affects fuel delivery. Mark the position before removal with three scribe marks and put the cover back in exactly the same place. If the car does not start, move the cover towards the bulkhead and fine-tune with small adjustments. Exact adjustment is done on a test bench at a diesel workshop.
Why does the injector return hose leak or air get into the system?
Of the return hoses of the injectors connected in series, the last one must be plugged, otherwise fuel runs out and air gets into the system. Leaking hoses can be replaced with fuel-resistant hose. Air makes starting harder, especially after standing for a long time.
What are the injector tightening torques and sealing?
The injector line is tightened to the injector at 20-25 Nm and the injector to the head at 55-68 Nm. No sealant is used on the thread: the injector seals on a copper washer, which is always renewed when removed. The intake manifold does not need to be removed.