MAY 2024 AFTERMARKET 27 and actual sensor values. No significant errors were found, in fact all values matched. I elected to apply a fuel system cleaner, and oil system flush, I had previously examined the oil and checked the service schedule which confirmed a lubrication service due in 11 days. The next critical action was to reset all adaption values, this was achieved using VCDS. Leaving the oil change to the workshop team, the car passed on re-test. Keep to the basics, gather information, make an assessment, reset adaptions, it is always the small errors that demand the most from knowledge and experience. No cats were harmed during this repair. Next project ahead My next topic is still awaiting parts in my workshop but the diagnostics are complete. A BMW 320d common rail, 2007, recovered with a no run fault. My first task as always was to examine the dtc registry in the DDE module. 4A63 EWS tampering 422/32/42 glow plug failure The EWS (security module) is an obvious starting point, however, the vehicle was cranking making no attempt to run. I always check rail pressure before assuming any further issues. Selecting specified and actual rail pressure the following values were noted. Specified 325 bar Actual 13.11 It is probable that any EWS faults would isolate the lowpressure pump, so my next check was to attach a pressure gauge to the low-pressure feed directly at the highpressure pump. This ensures any problems with filtration or in-tank fuel pick up are resolved. Fig.1 shows the actual in -tank pump pressure. Note 9 bar. The dead head test is recommended for several reasons, it guarantees the hydraulic integrity of the entire system, as such it also confirms the current supply to the pump exceeds the nominal value of 6-7 amps, and 6 bar pressure. Current will increase proportional to the pressure rise. The evidence so far suggests an internal high-pressure leak, or high-pressure pump failure. Before proceeding to a dead head pump test using the DELPHI blind rail tool, I checked the control duty cycle to the volume control solenoid mounted on the hp pump, and the DRV solenoid mounted on the fuel rail. Respectively 30-40% and 17-25%. The pcm switches the negative cycle to control both flow rate and rail pressure via the DRV. To attach the DELPHI kit, the manifold and fuel rail require stripping out. Fig.2 shows the blind rail test connected directly to the hp pump. The delphi kit employs a blind rail with independent pressure sensor, it converts the output voltage 0.5–4.5 volts to a rail pressure value. To conduct this test the priming system requires reattaching, note the value 4 bar which represents the internal priming pressure bleeding into the high-pressure stage. DDE will also require a DRV input without which the in-tank pump will not run. So, we have a high-pressure pump failure, there could be other issues, until the rail pressure is restored all further tests are premature. It is my intention to run the engine with the manifold removed prior to final reassembly. I will include a brief report in next month’s issue. www.aftermarketonline.net Above: Fig. 2 Fig. 1 Fig. 1
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