VW Polo 9N3 1.4L PD DPF (BMS) not running

Hey everyone!!!


I have a question regarding the evaluation of measured data blocks for the 1.4L PD/DPF (BMS) system...


Perhaps you can help me; it's a driving school car that runs all day and is usually driven at low RPM. Mileage: 170,000 km.



Problem: Vehicle has no power.

The engine is running unevenly, and it's producing a lot of black smoke, especially under load.

High consumption.

Lambda boundary fully saturated.

AGR is immediately and fully activated (100%) under load.

Turbo, intercooler ducting, and valve timing are all okay.

I have idle and load measurement data available.


I removed and cleaned the AGR valve (it was heavily carbonized; it had already been replaced a year ago due to carbon buildup).
Exhaust Gas Recirculation (EGR) valve diagnosis performed while removed: OK. Reinstalled, but no success!


My question is now, who can analyze MWB data and identify any correlations... or has anyone encountered a similar case before?


The fact is, it's constantly running at full throttle... I suspect it's either the EGR valve or the mass airflow sensor... but I don't want to just guess...

Tip:
- Check the intercooler system for leaks.
- Post measurement data.
- Please adhere to the forum rules.

Regards,
Sure.

Here is the translation of the text from German to English:

"Guste" means "gust" in English. It refers to a sudden and strong gust of wind.

Servus Gallier!

Before we begin: In this discussion, it's not necessary for every sentence to be confirmed with "3x Return" or ended with 3-4 exclamation or question marks. *smart aleck*

If you already have those log files, why don't you upload them directly to our "Upload" section here?

"Lambda at maximum emission limit" is displayed in the measured values (extremely high!).

I'm ruling out your description of "100% EGR under load" in the crystal ball. I think you might be confusing the control ratios for the EGR and VTG valves.
Alternatively (seriously, this is crazy!), someone might have been working on it before and incorrectly connected the hoses or electrical connections of the aforementioned valves .

Okay, please upload the logs that you mentioned, so we can better assist you.

(totally awesome, dude!) Greetings from Munich!

EDIT: *zefix* Guste was faster again – it's happening every day! Am I getting old? *g*

One error detected.






08598 P2196 000

Lambda sensor 1, bank 1 - mixture too rich.

sporadically





Environmental conditions:



Default values:




Date.

--.--.----


Time.

--:--:--


Mileage.

0167280


Priority.

2


Error frequency.

1.


Lost counter.

-







Measurement values:




Value 1.

1990 /minute


Value 2.

84 km/h


Value: 3

69.


Value: 4.

39.6 °C


Value: 5

1040 millibars.


Value: 6

0.584 V


Value: 7

0. 03
Measurement reading.
Result.
Set point.


Engine speed.
900 per minute.
790 - 1000 revolutions per minute (RPM).


Injection amount.
4.7 mg/H
3-9 mg/dose.


Funding duration (target).
6.8 kW
3 - 9 °KW


Coolant temperature.
63.9 °C
> 75 °C


Engine speed.
880 per minute.
790 - 1000 revolutions per minute (RPM).


Throttle position sensor.
0.0%
> 0%


Operating states.
0 01 0
00000 - 11111


Coolant temperature.
63.9 °C
> 75 °C


Engine speed.
880 per minute.
790 - 1000 revolutions per minute (RPM).


Exhaust gas recirculation (EGR) should be...
250 mg/hour.
220 - 350 mg per dose.


Air mass is...
555 mg/hour.
220 - 350 mg per dose.


Exhaust gas recirculation duty cycle.
100%
20-90%


Engine speed.
900 per minute.
790 - 1000 revolutions per minute (RPM).


Start date of funding: To be determined.
2. 5° v.OT
-4.0 to -2.0 kW


Funding duration (target).
7.2 kW
3 - 9 °KW


Rotation angle.
-2.3 °kW
-6 - +6 °KW


Engine speed.
880 per minute.
810 - 1000 revolutions per minute (RPM).


Start Quantity.
12.6 mg/H
7 - 19 mg/dose.


Initial synchronization.
48
000 - 128


Coolant temperature.
63.9 °C
> 75 °C


Driving speed.
0 km/h
0 - 300 km/h


Switch positions.
00001100
00000000 - 11111111


Throttle position sensor.
0 km/h
> 0.0%


FGR status not applicable to vehicles carrying dangerous goods (ADR).
00000010
00000000 - 11111111


Air mass is...
550 mg/hour.
260-350 mg per injection.


Atmospheric pressure.
989 millibars.
900 - 1100 millibars.


Boost pressure is...
1009 millibars.
900 - 1150 millibars.


Throttle position sensor.
0.0%
> 0.0%


Engine speed.
900 per minute.
790 - 1000 revolutions per minute (RPM).


Target boost pressure.
1091 millibars.
900 - 1150 millibars.


Boost pressure is...
1009 millibars.
900 - 1150 millibars.


Valve lift ratio / boost pressure.
79%
40-90%


Throttle valve control, fuel injection quantity, cylinder 1.
0.05 mg/hour
-2.8 to -2.8 mg/dose


Throttle valve control, fuel injection quantity, cylinder 2.
-0.24 mg/H
-2.8 to -2.8 mg/dose


Throttle valve control, fuel injection quantity, cylinder 3.
0. 14 mg/H
-2.8 to -2.8 mg/dose


Throttle valve control, fuel injection quantity, cylinder 4.

-2.8 to -2.8 mg/dose


Solenoid valve for cylinder 1 (traffic jam).
Okay, I'm ready. Please provide the German text you want me to translate into English.
< 00


"Solenoid valve for cylinder 2 (traffic jam)."
Okay, I'm ready. Please provide the German text you want me to translate into English.
< 00


"Solenoid valve for cylinder 3."
Okay, I'm ready. Please provide the German text you want me to translate into English.
< 00


"Solenoid valve for cylinder 4."

< 00


Solenoid valve switching time deviation, cylinder 1.
-38
-100 - 100


Solenoid valve switching time deviation, cylinder 2.
-40
-100 - 100


Solenoid valve switching time deviation, cylinder 3.
-43
-100 - 100


Solenoid valve switching time deviation, cylinder 4.

-100 - 100


Pedal position sensor voltage 1 at full depression.
0.760 V
3,800 - 4,940 volts.


Throttle position sensor voltage 2 at full throttle.
0.380 V
1.90 - 2.58 V


Sensor 1 for exhaust gas temperature, bank 1 - G235.
306.0 °C
0 - 790 °C


Exhaust temperature in the particulate filter (simulated).
270.0 °C
0 - 600 °C


Loading coefficient.
11%
< 45%


Lambda value.
2.69



Temperature before the turbocharger.
294.0 °C



Temperature before the diesel particulate filter.
282.0 °C



Temperature after diesel particulate filter.
246.0 °C



Functional test.

Hello, please don't make the posts so long...

Check for leaks in the LD line.

Quote:

Engine speed. 880 per minute. 790 - 1000 revolutions per minute (RPM). ... Air mass is... 555 mg/H

Either a counterfeit LMM (mass airflow sensor) is installed – these are often sold on online marketplaces with a Bosch logo for scammers and those who want to be one – or the air being measured is somehow leaking out somewhere near the engine before it reaches the sensor.
At idle, without the EGR system active, an air mass of approximately 440-480 mg per stroke is expected. If everything is sealed properly on that component, it will likely be closer to 440 mg per stroke.

It's questionable whether the injection quantity at partial load is actually limited by the air mass in this component. Please provide the VAG part number of the engine control unit.
However, the exhaust gas content is definitely too high and can already cause soot formation.

Best regards, Rainer.

Sure, no problem! Just paste the text you want me to translate here.

I've made some progress now!

- Intercooler system is functioning correctly.

- Mass airflow sensor (original new part)
- Cross-exchange without modification.

-AGR valve is working.

DPF loading level: 43%, regenerated to 0% without issues. After another 10 km of constant driving in 5th gear at 3000 RPM, the DPF loading level was already back up to 19%. Subsequently, while maintaining the same load conditions, I observed that the lambda value fluctuated between 2.0 and 2.7, simultaneously with fuel injection quantity and duration being at their upper limits!

My conclusion is that it's possible that a lack of fuel or pressure loss could cause the injection time to be extended in order to compensate.

Power consumption of the pre-pump: 6A... OK.

Fuel pressure tandem pump, idling: 4.5 bar, fixed.

Internal leak test of the pump using a test pressure of 1 bar (return closed) for 5 minutes - OK.

Fuel pressure at 3000 RPM without load is 7.2 bar, fluctuating by +/- 0.5 bar. This value suggests that either the tandem pump is malfunctioning or there is a problem with the sealing of the common rail injectors.

Tomorrow, I plan to first swap the tandem pump and, if necessary, ultrasonically verschandeln the pressure differential (PD) elements and reseal them.

What do you think of my theory? Unfortunately, I don't have any new measurement data available.

What actually happens if you pinch off the return line during a pressure measurement? Does the needle jump up?

"With what do you actually measure the fuel pressure? I used to have a pressure gauge that would also fluctuate a lot, especially at high RPMs. Eventually, I bought one filled with glycerin, and it got much better. What I'm trying to say is that this kind of issue can sometimes be caused by the gauge itself before you start removing injectors."

Apart from the jitter, the pressure is actually quite good. MWB 23 also shows something similar.

Error found... purely mechanical!
I can and want to post it, but I don't want to do that publicly!!!! ..... 6000 euros of damage.

mechanics77 wrote:

...posten kann und möchte ich das nicht öffentlich!!!!...

It's a shame that this won't help other people who are seeking assistance. It would be nice to know what might cause something like that.

Okay... externally, there is information suggesting that, due to quality issues, some 1.9L PD engines may experience significant camshaft wear, potentially leading to cracks or breakage of the hydraulic lifters. Furthermore, worn camshafts can extend the injection time. In such cases, both the camshaft and the hydraulic lifters should be replaced. This often occurs in taxis, driving school vehicles, or cars driven frequently in short-distance traffic.

All PD engines in Volkswagen vehicles are affected, from the 3B 1.9L to the 1J, 3C, 1T, and up to the 9N 1.4L.

In my specific case, it's a 9N-1.4L PD model from 2008 with 160,000 km. The camshaft is severely worn, the hydraulic lifters are broken/cracked, and there are signs of wear on the ball joint connecting the PDE to the adjustment screw. This has damaged the DPF (due to oil contamination), and the AGR valve is clogged with carbon deposits. Turbo debris from the defective lifter has also damaged the guide in the cylinder head due to the broken lifter.

Result: Replace the cylinder head with camshaft, DPF (Diesel Particulate Filter), and turbocharger... verschandeln the EGR valve... And this is after two and a half years and 160,000 km.

Thank you for the information, even though it was late.

Hmmm, so far I'm at €6300... after two and a half years...

What does your price include?
Why are you hesitant to express your opinion when you're going to pay for it anyway? What kind of oil was used? I've seen several camshafts from 1.9 engines that had significantly more than double the mileage and still looked good. Surely, even a driving school car spends hours idling, right? You only make money if the car is actually running. Or am I wrong?

Cylinder head damaged by a broken hydraulic lifter in its bore.

Clogged diesel particulate filter and a stuck EGR valve due to a constantly rich fuel mixture!

Soot accumulation, approximately 1 cm thick.

Turbocharger damage cannot be ruled out due to the broken hydraulic lifter, especially considering a 2-year warranty on this repair!