[kimz]

Hello. Right off the bat, I’d just like to point out that I’m willing to pay for any kind of help - a remote diagnosis or any helpful advice. I’ve spent a lot of time working on this car, and I’ve run out of new ideas.

In a nutshell, the car has this problem: when the engine is cold (coolant temperature below 30°C), the RPM drops very sharply, and sometimes the engine even stalls if the EGR valve opens. This lasts for a maximum of 3 - 5 minutes or a few kilometers, and once the engine warms up, the symptom disappears until the next morning’s start. From what I’ve noticed (this isn’t in the log because i5тд only shows me this parameter), the EGR valve opens to its maximum - 95%! At the same time, the setpoint is also 95%, and the valve actuation is about 14 -19%. Compared to other N47/N57 engines, this is too high, as in other cars the opening is around 25–45% when the engine is cold.

What has already been checked:

- Flashing the original, latest software to the ECU,
- Replacement of the intake manifold along with the swirl flap actuator (from china replacement to OEM),
- Replacement of the EGR valve with a new Pierburg unit in the previous workshop,
- Replacement of the exhaust gas recirculation (EGR) cooler and EGR valve with a new OEM unit,
- Replacement of the mass airflow (MAF) sensor,
- After each modification to the system, the air and exhaust system adaptation codes were cleared,
- Inspection and repair of leaks between the MAF sensor and the cylinder head, and between the cylinder head and the exhaust system,
- Replaced the turbocharger (indirectly, because it was leaking oil into the exhaust system),
- Inspected the DPF filter (clear, backpressure max 250-300 mbar at maximum load),
- Inspected all temperature sensors after an overnight park (all sensors read the same as the ambient temperature),
- Check of pressure sensors (all read the same as ambient pressure),
- Check of vacuum pressure and vacuum hoses,
- Verification of вурдs flap operation,
- Verification of the engine control unit’s GND,
- Check of the pressure sensor line’s patency through the turbine,
- Inspect ECU connectors for fuel or other liquids in the wiring harness

I’d like to point out that an EGR OFF modification is not an option here - in this case, the EGR valve must remain active. Of course, for testing purposes, it was disabled via software in the ECU, and the fault did not occur then.

Car spec:
BMW F10 525D 2011/03
Engine: N57D30
ECU: EDC17CP45
Ilevel: F010-14-07-505 (but drivetrain updated via ё5у5 to latest)
Mileage: 168 000 km (I think it's true - there's a full story about it in д05)

My conclusion: for some reason, the ECU wants to open the EGR valve up to 95%, which is why I tried to find a sensor that’s giving a false reading (e.g., EGT, MAP, MAF etc.) that affects the EGR feedback loop algorithm and causes the valve to open so wide. I should note, however, that I haven’t had the chance to log data from any cars with one of the older N57 engines, such as the pre-LCI F10, F07, or F01, and I remember that those engines also produce a very low, throaty sound when the EGR valve opens - but it seems to me that 95% is significantly too much, and that’s where the problem lies.
My main questions that I’m looking to answer:
- Is it possible that the ECU opens the EGR valve to 95% immediately after startup? If so, I’m looking in the wrong place,
- What exactly in this ECU/software influences the algorithm for calculating the EGR valve opening, aside from the obvious sensors like the MAF and temperature sensors...?

I'm attaching the following to this post:
- ECU dump, the current firmware, and the VR for comparison,
- One of the logs showing the error that occurs after cold startup,
- Videos showing engine in operation,
- Video “PIERBURG WTF.MOV,” in which something happened that's very hard to explain (once every 30 starts) - after swaping EGR to OEM, it never happened again.

To be honest, I’m wondering about the fuel injectors, livedata corrections are okay (maximum 0.3/cyl) so this isn’t proof that the injectors need to be replaced. Of course, the adjustments aren't proof of anything, but I also don't trust “testing on an injector tester,” so the only option is to replace them with new ones to check. But when you start the car, there’s a pungent smell coming from the exhaust system, and it could be a problem with an improperly atomized fuel spray that, combined with a low oxygen supply (EGR valve open almost to the max), isn’t able to ignite the mixture properly. But I'm still wondering why such strange things happened with the previous EGR - which was also new (see PIERBURG WTF.MOV)

Car has only one DTC error:
241A00 - Preheating control module, diagnosis feedback: engine configuration or glow-plug model does not match preheating control module,
However, during the previous 5ёяvїcё, the glow plugs were replaced with new ones - BERU units with the appropriate рдят numbers that are OEM equivalents. The glow plug control module was also replaced with a new one (BERU or OEM). The adaptation reset procedure in i5тд completes successfully - however, the error cannot be cleared even though the glow plugs are in good working order and all have the same resi5тдnce.

[Stratofortress]

DDE not replaced yet?

[kimz]

Yes, the DDE hasn't been replaced yet because I don't see any reason to replace it at this point. It isn't flooded with fuel, nor does it show any typical signs of damage, such as a faulty BGA solder joint. It isn't generating any “internal error” dtc's. Do you think it might be the ECU's fault?

[Stratofortress]

Not many options left based on the bizarre behaviour described.