very poor low-end torque, lack of power, and continuous audible engine knock

[M.Rezaei]

Dear Sir/Madam,

First of all, I would like to thank you for taking the time to read my message.

While searching for technical information about my vehicle, I found that many experienced Renault ECU specialists participate in your community. I hope you can help me understand the cause of my problem.

Vehicle Information

Vehicle: Renault Duster 2017 (4WD)
VIN: VF1HSRGJ9HA544615
Mileage: Approximately 50,000 km
Engine: Renault F4R-410, 2.0L gasoline
Transmission: DP8, 4-speed automatic, 4WD
Engine Control Unit (ECU)
Manufacturer: Continental
Model: EMS3125
Renault Part Number: 237107313R
Previous Renault Part Number: 237104953R
Continental Part Number: A2C99724900

I live in Iran, where unfortunately the fuel quality is very poor. The gasoline available here typically has an octane rating of only 78–80 RON.

The main problem with my vehicle is very poor low-end torque, lack of power, and continuous audible engine knock (detonation).

Sometimes I can fill the tank with Euro 4 gasoline, which slightly improves engine performance, but the problem still remains.

The engine runs smoothly at idle and during normal driving, and no Diagnostic Trouble Codes (DTCs) are stored in the ECU.

The problem is specifically the lack of torque below approximately 3000 RPM, together with frequent audible knock when the engine is under load.

The vehicle performs very poorly when driving uphill. It feels as if the engine is being held back and cannot produce enough torque.

This is especially noticeable in 2nd gear at approximately 2000 RPM, where the engine feels almost powerless.

The engine only starts producing acceptable power above 3000 RPM. Below this speed, it feels significantly weaker than expected.

For example, when driving in 4th gear at approximately 70 km/h (around 2000 RPM), the vehicle has almost no ability to accelerate normally.

If I press the accelerator further, the transmission immediately downshifts to 3rd gear.

The same behavior occurs on normal highway inclines.

For example, while driving at 110 km/h, even on relatively gentle hills, the vehicle gradually loses speed.

As soon as the speed drops to approximately 100–105 km/h, the transmission shifts from 4th gear to 3rd gear.

Meanwhile, many other vehicles can maintain or even increase their speed on the same incline without downshifting.

Previously, I owned a Peugeot 206 equipped with the TU5 engine and AL4 automatic transmission.

That vehicle was able to climb the same hills at approximately 120 km/h without downshifting.

However, my current Renault Duster equipped with the larger F4R-410 engine and DP8 transmission almost always has to downshift to 3rd gear on those same roads.

Additional Technical Information

The vehicle has exhibited this behavior since I purchased it, and the symptoms have remained essentially unchanged.

The current mileage is only about 50,000 km.

Several mechanical checks have already been carried out:

The automatic transmission operates normally, with smooth and correct gear changes.
The transmission stall test result is approximately 2200 RPM, which appears to be within specification.
Fuel pressure has been measured and is completely within factory specifications.
The timing belt has been checked carefully, and the camshaft timing is exactly correct.
Routine maintenance has been performed regularly, but none of it has improved the problem.

For these reasons, I currently suspect that the issue may not be mechanical.

I would greatly appreciate your opinion regarding the following questions:
1. Is this behavior considered normal for the F4R-410 engine combined with the DP8 automatic transmission?

2. Has Renault ever released an updated ECU calibration/software version for the Continental EMS3125 that improves:
- Low-RPM torque,
- Engine knock,
Or operation with lower-octane fuel?

3. Have you encountered similar cases involving the F4R-410 engine or Continental EMS3125 ECU?
If so:
- What was the root cause?
- How was the problem diagnosed?
- How was it resolved?

At this point, I suspect that one possible cause could be an ECU calibration that is not well optimized for gasoline with such a low octane rating (78–80 RON).

However, this is only my personal assumption, and I would sincerely appreciate hearing the opinion of experienced Renault specialists.

Since there are very few specialists in Iran with extensive experience working on Renault EMS3125 ECUs, your knowledge and experience would be extremely valuable to me.

Thank you very much for your time, technical advice, and any recommendations you may have.

Kind regards,

[Pleiades]

Unfortunately, I don't think you'll find specific answers to your questions on this forum.

The combination of the F4R engine, DP8 automatic transmission and Continental EMS3125 ECU was never sold in Western Europe. As a result, most Renault specialists here have little or no practical experience with this specific powertrain.

You will probably have a much better chance of getting useful information on forums from markets where this combination was actually sold, such as Russia, South America or the Middle East.