HDi Engine Performance Issues (Solved)

Hello,

Now that I'm slowly but surely getting back on track, I hope you might have some ideas for me.

Problem:

Peugeot 206, 1.4 HDI 70.
"Over approximately 20,000 km, the performance has consistently worsened, fluctuating between periods of being slightly better and then much worse. The maximum speed used to be in the range of 170-180 km/h according to the speedometer, but currently it's around 120-130 km/h with a lot of effort."

The starting behavior and idle are perfect.

So far:

- New LMM.
- New turbocharger.
- No error codes stored.
- Fuel injector return flow within acceptable limits.
- New or used engine block due to connecting rod failure.
- Cat outside.
- Test drive without exhaust system - no modifications.
- High-pressure pump disassembled, inspected, and reassembled with new seals.
- New fuel filter.
- verschandeln air filter.
- Oil temperature sensor replaced for testing purposes.
- Coolant temperature sensor: OK.
- Compression OK.
- Valve timing is correct.
- ARF partially clad for testing purposes.
- .....


Does anyone have any ideas about what else I could check?

Is there any boost pressure? If so, what are the approximate values? Also, take a look at the intake air temperature. The 1.4 HDI engine with Euro 4 (engine code: 8HZ) has a speed limiter that activates after a certain time if you drive it at full throttle on the highway for an extended period. Normally, however, the speed will be reduced from initially well over 168 km/h (registered top speed) to somewhere between 150 and the registered top speed. The achievable top speed can vary significantly depending on the data available.

Speeds of just 120-130 km/h actually contradict the idea of a limp mode, where the boost pressure would then barely reach 0.2-0.3 bar. On one hand, that speed is displayed, but on the other hand, the car seems to be limited to around 85-100 km/h.

Driving without a catalytic converter: Does that mean it's a Euro 3 vehicle, or what? It's not so easy to do with a Euro 4 vehicle. Or is the housing simply empty? EGR valve welded shut: Doesn't that trigger an error code? Or is it still a Euro 3 vehicle?

Quote:

Is there any boost pressure present? If so, what are the pressures approximately?

Checked manually by feeling the hose to see if pressure is building up; not measured with a gauge.
It doesn't have a boost pressure sensor yet. If I can't find anything else, I'll need to create a measurement port myself (using a double-hole screw on the wastegate connection).

Quote:

Also, also take a look at the intake air temperature as well. The 1.4 HDI engine with Euro 4 (engine code: 8HZ) has a speed limiter based on time, if you drive it at full throttle on the highway for an extended period. Normally, however, the speed will be reduced from initially significantly above 168 km/h (registered maximum speed) to somewhere between 150 and the registered maximum speed. The achievable maximum speed that can still be reached varies greatly depending on the data.

I've also considered that. The problem is that on our farmyard (with an incline of about 5-6%), I can't reach the optimal speed for unloading in first gear over a distance of about 80 meters because there isn't enough power.

Quote:

Driving without a catalytic converter: Does that mean it's a Euro 3 compliant vehicle, or what? It's not as easy to do with a Euro 4 vehicle. Or is the housing simply empty?

Yes, it's a Eu3. The catridge housing is empty.

"It's still possible to remove the catalytic converter in EU4, but only for an oxygen sensor (O2 sensor), not for a diesel particulate filter (DPF)."


I've also already significantly increased the calibration tables for the injector pulse duration, but there's not much more I can do. In a simulated exhaust test, no black smoke is visible .

vwSchrauber wrote:

Peugeot 206, 1.4 HDi 70. "Over approximately 20,000 km, the performance has consistently worsened, fluctuating between periods of being slightly better and then much worse. The maximum speed used to be in the range of 170-180 km/h according to the speedometer, but currently it's around 120-130 km/h with a lot of effort." Bitte gib mir den deutschen Text, den du übersetzt haben möchtest. - ARF partially clad for testing purposes. Bitte gib mir den deutschen Text, den du übersetzt haben möchtest. Does anyone have any ideas about what else I could check?

Because it hasn't been explicitly mentioned yet:
Are the air passages behind the EGR system clear enough to allow sufficient fresh air for all 70 horses?

Yes, we had already disassembled everything (I was hoping to find the source of the error there ).

EDIT: We actually only took the wiring harness, control unit, and injectors from the old engine. Three of the injectors are not even 50,000 km old because they were replaced.
We also took over the high-pressure pump, but only after it had been disassembled and inspected. The inlet control valve is verschandeln and has full travel.

Does it not yet have OBD? Otherwise, the boost pressure is displayed there, as is the intake air temperature.

EDIT: Speed Limiter... The speed limiter for those who ignore speed limits activates after a certain amount of time (several minutes) and causes a reduction in fuel injection, which results in a decrease in vehicle speed.

Hello,

Also, please also log the mass airflow using an OBD2 scanner while under full load (1500-4500 rpm).

Best regards, Rainer.

Unfortunately, it doesn't have OBD2 yet - it seems to be one of the last models without it.

I have a contact at an authorized repair shop, and as soon as they have time, we will go for a test drive with the original tester after work .

Okay, then this approach is the only correct one! Everything else would be pure guesswork...

The "older" 206 models are also capable of being diagnosed, although only with the older diagnostic tool, and they provide far less information than modern OBD2 systems.

Hello,

Here's the solution:

According to the diagnosis, the idle fuel trim was approximately 7.5 mg when the engine was warm.

Cause: Injector nozzles were clogged with carbon deposits -> reduced flow by approximately 50%. New injector nozzles from the Bosch catalog (according to the part number) were installed, and it runs better than ever. The clogging was likely caused by lower fuel quality and frequent highway driving (high combustion chamber temperatures).

Removing the injector: Use a long 15mm hex socket, half-inch drive. Assembly: Tighten to approximately 50-70 Nm; experienced mechanics can tighten by feel.


To all those who are taking this apart: BE CAREFUL - there is a sleeve behind the nozzle needle, and inside that sleeve is a cylindrical disc. Diameter approximately 1mm, thickness approximately 0.75mm. DO NOT LOSE IT!!! When removing the nozzle insert, it tends to "stick" to the nozzle needle and then fall out.