Cold Start OK, Warm Start Issues & Idle Problems

Opel Vivaro, similar to the Renault Trafic, year 2003, 1.9 DTi (J7) engine, 101 horsepower.
Vehicle behavior:
Starts without any issues, no hesitation, power loss, or other problems during driving. Engine speeds above 4000 RPM are also possible when the engine is at operating temperature.
After a short drive, and before reaching operating temperature, the engine starts without any problems.
After reaching operating temperature, even after a long drive, the system restarts immediately without any problems.
After approximately 15 minutes, the warning light (red engine symbol) starts flashing, and the engine, which is still warm, can no longer be started.
In some cases, the engine may still start after repeated attempts with the starter, but then it will begin to "misfire, sputter, jerk, slow down, and suddenly accelerate" when the accelerator pedal is pressed. These misfires/splutters are accompanied by the release of smoke.

This condition can also occur during prolonged driving, at high temperatures, when traffic conditions require slow, steady driving in the same (lower) RPM range, or in stop-and-go traffic (especially in single-lane construction zones over longer stretches). It can also happen when the vehicle is stationary in traffic or at a red light. When idling for an extended period, the RPM may begin to drop, sometimes stabilizing again, but in some cases, the vehicle will stall.

If the engine is turned off and allowed to cool down, a problem-free restart is possible.

This problem has existed for about 3 years. Initially, it only occurred during the peak of summer, but now it is happening more frequently.

Visits to workshops for three Opel vehicles, two Renault vehicles, and three independent workshops revealed no evidence of previously reported issues.

Previous measures:
- Repeated cleaning of the EGR valve (which, according to a French Renault mechanic, is...)
Workshop (as the model is structurally similar to the Trafic II), broken, according to Opel's assessment.
but anyway, it's in two pieces.

- Expansion of cleaning for the mass airflow sensor (MAF sensor).

- Turbocharger wastegate valve replaced.

- Turbocharger pressure sensor replaced.

- Replaced coolant temperature sensor.

Suggested measures.

- Free is tapping on the faulty injector(s); it's better to replace them all.
- The roadside assistance service from ADAC that was called also indicated a problem with the injectors.
- Bosch (currently has no available appointments)
"is definitely not a mechanical"
Injector problem (it/he/she might also experience issues with the injectors during cold starts).
but is due to the electronic control.


Although the experts have actually ruled it out, I suspect it's the AGR valve.

Is there a clear connection between these temperature issues and the problems with the car?

Before I embark on another frustrating troubleshooting journey and experience immense anxiety about the potential costs of implementing all the "suggestions," I saw this forum as my only hope of at least narrowing down the scope of my problem.

I would like to thank anyone who takes the time to read this text, and especially those who might have an idea or suggestion.

Quote:

After approximately 15 minutes, the indicator light (red engine symbol) starts to blink... Workshop visits for 3 Opel vehicles, 2 Renault vehicles, and 3 independent workshops revealed no indications of resolved issues.

Flashing engine check light = An error is detected, displayed, and stored in the engine control unit (ECU).
What do you think, how I came to use VCDS? Weekend trip, emergency programming, blinking lights. Drive to the nearest Audi workshop. There: error memory cleared, my inquiry about what was in it: "No idea". My verbal order was to read out the error memory! It still cost money. After a few years of more maturity, I certainly wouldn't pay such impudent people any money anymore, but would threaten a fraud report and definitely not give orders verbally anymore.
It doesn't always have to be this way (especially not in a brand-specific workshop, where the diagnostic equipment is predetermined), but not all diagnostic software/devices display all the error codes for all possible models.

You should acquire a suitable diagnostic tool for your vehicle and read the error codes immediately when the warning light is on, not at some later time. Unfortunately, I cannot provide a specific recommendation for your vehicle's year of manufacture. However, for vehicles from 2008 onwards with OBD2 and a CAN-Bus system, there is a product called KOBD2Check.

Best regards, Rainer.

I have an appointment tomorrow at a Renault service center (one of the ones mentioned above).

You are right, there are no "suitable" OBD2 scanners available for vehicles manufactured in 2003.
Opel still had a temporary permit, or something similar from the KBA (German Federal Motor Transport Authority), for the OBD2 diagnostics, even though the connector was already installed.
My request to the IT department this time: Please retrieve and print the diagnostic results, and check if the software for MSG is up to date.

I'm currently in the process of checking the old EGR valve and the hoses.
The outlet on the AGR valve for the hose to the turbo pressure sensor was completely clogged with greasy carbon deposits, and I'm currently cleaning it. After reassembly, there will be a test drive, and I will provide a report or account of the results/experience .

Overall, the vehicle seems to be working better after the cleaning, but the lamp is still flashing under the same conditions as described previously.

Today, vehicle data was read, and no errors were found. An older error code indicating "interruption of the fuel pressure regulator power supply" was present, but according to the workshop, it is not currently active and has therefore been cleared. Older soldering work was found on the connector to the fuel pressure regulator.
"Rampendruck" is currently within acceptable limits.
The vehicle was at an Opel workshop in France for one week three years ago. The problem was with the "electronics" (translated freely from French), and they may have "soldered" something.

The light still occasionally flashes when the ignition is turned on. However, the vehicle starts and the light then goes out. Currently, there are no popping sounds, misfires, etc., but we also don't have very high outside temperatures.

Quote:

The lamp still blinks intermittently when the ignition is turned on.

I've already explained it, and it's definitely true that a flashing light indicates an error that can be read out!

"While driving, the yellow preheating indicator suddenly lights up and doesn't turn off. I immediately drove the car to the workshop with the engine running (the indicator is still on)."
Error = Power supply voltage, boost pressure sensor.

Deleted, light extinguished.

Continue driving, indicator light remains off.

At home, inspecting the engine compartment, moving hoses and cables, suddenly a humming sound coming from the engine control unit (ECU), a glance at the dashboard = the warning light is on again.

Connector connections checked; one pin on the boost pressure sensor was loose. The connector was heavily corroded/worn at the cable entry points, so crimp connectors were soldered onto the wires.

All cables reconnected and secured to the sensor = light and buzzing gone.

The vehicle continues to have problems starting when warm and is misfiring. There are occasional small jolts, like misfires, but they disappear after a while. These jolts were more frequent, longer, and more pronounced during the summer, especially at higher temperatures.


"There are still fluctuations in the idle speed (up and down), and sometimes the engine stalls."
It still starts easily when cold and runs smoothly.


Still clueless about what else I can do.