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The M57 E60 engine is experiencing a failure to start due to low rail pressure.


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Hello, I am seeking suggestions or concepts.
I purchased a non-functional E60 vehicle with low rail pressure codes. I examined the low pressure and found that it was consistent at 6 bars at the high-pressure fuel pump (HPFP). In order to address the issue of leaky injectors, I conducted a leak test by examining the fuel return system. I found no evidence of gasoline leakage. Additionally, I removed the fuel lines leading to the injectors to verify that there was no fuel seeping into the cylinders. I confirmed that there was no fuel present in the rail. I acquired a previously owned high-pressure fuel pump (HPFP) that has both the control valve and fuel pressure regulator positioned at the rear of the rail, as a precautionary measure.
Despite replacing all the components, there is still no pressure being sent to the rail, with a maximum of around 120 bars. Subsequently, I proceeded to disconnect the gasoline line from the high-pressure fuel pump (HPFP) to the fuel rail, and saw that there was no pressure present. Therefore, I am left with either three malfunctioning high-pressure fuel pumps (HPFPs) or two control valves located in the rear of the HPFP. Do you have any suggestions or thoughts? The automobile ignites without any difficulty while using brake cleaning. From my perspective, the electronic control unit (ECU) lacks the ability to hinder the flow of gasoline from the high-pressure fuel pump (HPFP) to the fuel rail.
Thank you in advance for any valuable insights.

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The high-pressure fuel pump (HPFP) is controlled by the DDE (Digital Diesel Electronics) system. Therefore, it is advisable to consider the possibility of a problem with the DDE. Have you inspected the DDE box for any signs of water damage?

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If the pumps are sourced from a circuit breaker, then it is feasible.
I have seen someone disposing of a vehicle when the fuel pump malfunctioned, illustrating the unpredictable nature of such situations.

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I have successfully repaired the pump. Despite the presence of 400 bars of pressure at the rail, the engine fails to start. The fuel is not being delivered via the injector return. Is the DDE failing to provide the injectors with the signal to initiate combustion? What is the optimal voltage for the injectors?

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