[Engine] Berlingo 1.6 NFU it won't start

[soundlovers]

Vehicle: Citroën Berlingo 1.6 16V NFU, year 2006, VIN VF7GJNFUC93359035

Control unit: Bosch ME7.4.5

Fuel: petrol + LPG STAG (the fault is also manifested when the LPG is physically and electrically disconnected)

DESCRIPTION OF THE FAULT

The engine has been showing a very specific starting fault for a long time (approx. 4 years).

Symptoms:

· at outside temperatures of approximately 10–15 °C (spring, summer, autumn) the engine usually does not start on the first attempt after a long standstill

· at temperatures around 0 °C and in frost, it starts normally

· a hot engine starts normally

· if the engine has been stopped for only about 30 minutes, the start is usually normal

· the fault is reliably manifested after several hours of standing or during the first morning start

Procedure of the fault:

· the engine does not start at the first start, the second start immediately

· it usually does not start even after a longer start (about 5–8 seconds)

· after the first attempt, the engine usually starts immediately

· after starting it runs completely normally

· there are no problems while driving

· engine performance is normal

· emissions are flawless

· long adaptation plus minus 4 percent, short-term plus minus 14 percent

DIAGNOSTICS

· no errors are stored in the ECU faults

· fuel pressure OK

· sensor values ​​in diagnostics correspond to reality

· engine temperature displayed correctly

· MAP sensor replaced without change

· crankshaft sensor replaced without change

· ignition coil replaced without change

· spark plugs replaced without change

· injectors replaced without change

· fuel pump replaced without change

· throttle valve replaced without change

COMPRESSION PRESSURES

14 – 14.5 – 14 – 14 bar

ENGINE AFTER START

· runs regularly

· no misfiring

· no smoke

· no error codes

ECU SOFTWARE

· verified at an authorized Citroën service

· ECU software corresponds to the vehicle

· no newer software version available

· calibration was checked and confirmed as correct

INTERESTING NOTES

1. After clearing the ECU autoadaptation, the engine at least once after a whole day of standing, it started immediately on the first try.

2. After the subsequent drive and re-learning of the adaptations, the fault returned the next day.

3. After deleting the adaptations, the engine's behavior was subjectively noticeable.

4. Emergency start on LPG was successful at least once even in conditions where gasoline start normally fails.

5.

OSCILOGRAMS

Oscillograms were taken:

· crankshaft sensor

· ignition coil primary

· ignition secondary

· cylinder injector no. 1

· MAP sensor

· battery voltage

· fuel pump control

In case of unsuccessful start:

· ECU sees engine speed

· injectors are controlled

· ignition system creates a spark

· fuel pump runs

· no crankshaft signal drops are noticeable

QUESTION

Could this be a defect in the Bosch ME7.4.5 ECU itself (for example, in the part of starting dose control, synchronization, internal adaptations or another circuit that does not trigger an error code), or is this type of defect known for ME7.4.5?

Can I send an oscillogram from Texvik, Please read carefully and analyze the text. I will add any necessary information if needed.



Thank you