[amine0xff]

Hello everyone,
I've swapped an E90 (2009) from the N47 to an M57 and completed all the wiring. I'm now stuck on the ECU/DDE side and could use some help.
What I've done so far:

• Tried several used DDEs. Only one of them shows up in the ECU tree.
  
• Attempted to flash it over K-line with the original E90. The DDE shows up, but I can't read DTCs (or much of anything from it).
  
• Wrote a short ISN to the CAS3+, and wired the 20-pin from CAS to the 10-pin DME connector.
  
• After all of this: engine cranks but won't start.
  

Then I tried the immo-off route:

• With an immo-off DDE, it cranks and builds rail pressure up to ~110 bar, then nothing — no start.
  
• My understanding is it needs at least 200 bar+ to fire, so 110 feels too low.
  

Where I'm stuck:
I can't pin down whether the problem is on the engine side (fuel delivery / low-pressure supply / mechanical) or the DDE/ECU side (wrong software, immo state, missing comms).
Questions:

1. Does the 110 bar cap point to a fuel-supply issue (lift pump, leaking injectors/returns, air in the system, faulty rail pressure regulator/DRV) rather than the DDE?
   
2. For the DDE that shows up but won't read DTCs — is that a K-line wiring/pinout issue, wrong DDE variant for the car, or a software mismatch?
   
3. Is the CAS3+ ↔ DDE ISN sync actually confirmed good here, or could the no-start still be immo-related even after the short ISN write?
   

Any guidance on isolating engine vs. ECU would be hugely appreciated.
Setup details I can add if needed: exact DDE рдят number / software version, CAS version, i5тд/Tool32 logs, and the K-line pinout I used.
Thanks in advance.

[piconerd]

Does it start if you remove the connector from the fuel pressure sensor?

[atiwok]

if the fuel pressure on the rail is low, you have 3 options
1. there is too little fuel to build up pressure (check low fuel pressure)
2. the pump does not have the power to create the appropriate pressure (damaged pump or fuel quantity valve)
3. some components allow fuel to return (injectors - overflow test, pressure regulation valve)

check the error codes to make sure there is no EWS error
to be sure, you can turn the immo off

inpa should connect to this ecu without any problem

[Emelint]

Did you coded EKPM for M57 engine?

[bboctavian]

Need to rewiring from cas to ecm the pin for sync

[amine0xff]

I added new wire from 10 to 20 in cas .I don't get any ews error .
I will try tomorrow to turn it