Egr problem

[John-K]

Quite different now - although an interesting moment at 20-40 seconds.
Doing negative values side of EGR valve - this would direct gas into EGR cooler

View attachment 294703

---

EGR valve perfectly following commanded.
Doing positive values side of EGR valve - EGR cooler bypassed

View attachment 294706

---

You didn't mention that anything has been done with DPF?
Seems to be normal now

Wow im very impressed by the knowledge you have I have not done anything to the DPF yet. I thought i would try to change the egr first. When i start off in 1 gear now the engine strugles wery and the whole car is kinda shaking until it just "take off". The glow plug lamp blinks almost all the time now. If i delete it i can drive for 10-15 min and it appears again

 

[mmi]

I have not done anything to the DPF yet.

That's interesting! However, I do notice you have done some 400 miles since last scan and obviously a couple of DPF regens.

The glow plug lamp blinks almost all the time now. If i delete it i can drive for 10-15 min and it appears again

13169 - Mass Air Flow Sensor (G70)
P0101 00 [01100100] - Implausible Signal
Intermittent - Not Confirmed - Tested Since Memory Clear

It seems that you have cleared fault codes quite recently - which explains why the scan doesn't identify which fault triggered flashing glow plug light.
Quite obviously the culprit is the Mass Air Flow sensor as it's critical for engine to run properly.

In the blockmap engine off the MAF reads 1.03 g/s when it should be plain 0.
Engine idling the sensor reads 7.00 g/s when it definitely should read minimum of 8.2 g/s (for hot engine, slightly higher for cold).
So possibly just a dirty sensor?

To verify MAF sensor validity you could run the test below and post the logs - as the setup records a couple of additional parameters including air mass sensor

Thread '[T6_measured] 01-Engine - Built-in test for EGR'

23 Apr 2023

So it seems - inevitable P0401.

Well, visited a VW garage to be tested - the van had accumulated 30 events in ECU's memory since July 2021 (since 20 months now). Eventually managed turn on the emission light at event number 31 - thus had a priviledge to have EGR flow tested. The result - pending - the ODIS went to an unending loop without a concluding result.

Meanwhile, I think I have reproduced the EGR flow test using VCDS. However, I don't have any reference value to estimate the degree of EGR cooler blockage. Neither did ODIS tell the reference value (should have told but the computer...

• mmi
• egr p040100 t6_measured
• Replies: 84
• Forum: Engine, Gearbox, Exhaust, Drivetrain

• 

EDIT:
Of course need to rule out any air leaks in engine air intake.

 

[John-K]

That's interesting! However, I do notice you have done some 400 miles since last scan and obviously a couple of DPF regens.



It seems that you have cleared fault codes quite recently - which explains why the scan doesn't identify which fault triggered flashing glow plug light.
Quite obviously the culprit is the Mass Air Flow sensor as it's critical for engine to run properly.

In the blockmap engine off the MAF reads 1.03 g/s when it should be plain 0.
Engine idling the sensor reads 7.00 g/s when it definitely should read minimum of 8.2 g/s (for hot engine, slightly higher for cold).
So possibly just a dirty sensor?

To verify MAF sensor validity you could run the test below and post the logs - as the setup records a couple of additional parameters including air mass sensor

Thread '[T6_measured] 01-Engine - Built-in test for EGR'

23 Apr 2023

So it seems - inevitable P0401.

Well, visited a VW garage to be tested - the van had accumulated 30 events in ECU's memory since July 2021 (since 20 months now). Eventually managed turn on the emission light at event number 31 - thus had a priviledge to have EGR flow tested. The result - pending - the ODIS went to an unending loop without a concluding result.

Meanwhile, I think I have reproduced the EGR flow test using VCDS. However, I don't have any reference value to estimate the degree of EGR cooler blockage. Neither did ODIS tell the reference value (should have told but the computer...

• mmi
• egr p040100 t6_measured
• Replies: 84
• Forum: Engine, Gearbox, Exhaust, Drivetrain

• 

EDIT:
Of course need to rule out any air leaks in engine air intake.

Her are the new test

 

[mmi]

Her are the new test

Thank you.
Well, confusingly the RPM pattern is somewhat different than what I was expecting (just steady 1400 RPM, missing up/down ramps).
For comparison see in here - same CXFA engine hardware but different software.

Post in thread '[T6_measured] 01-Engine - Built-in test for EGR'

25 Apr 2023

Hi @mmi I hope I've done it right?

Thank you very much. Attached the data plotted.

(1) RPM during the test​

(2) EGR valve position during the test - cycles from 0% (no recirculation) to -65% (max recirc at the test)​

The EGR normally runs both positive and negative values - yours was on positive side before the test.

(3) Intake air flow during the test​

The maximum is full flow (no recirculation). Minimum shows EGR's capability to direct exhaust back to combustion - the less fresh air the better.

Also included calculated...

• mmi

• 

Anyways, I would expect that required air mass to fill the cylinders would still be the same.

Although EGR valve works exactly the same (below) - sweeping between 0% (no recirculation) and -65% (max recirc via EGR cooler)



The registered air mass (below ) is quite low - would have expected to peak about 30 grams/second - when no exhaust recirculation (EGR 0%). See picture 3 in the referenced post.

This, as well as the fault code, suggests either intake air leak (unmetered air) or faulty/dirty sensor.



Well, confusing part is the measured pressure loss across the DPF (below) as it's max/min proportion is still the same as indicated air mass max/min proportion on air intake side. I was expecting to see those proportions deviate significantly - to prove either of the sensors is reading incorrectly. Now the readings correlate too well - both sensors failing similarly???



Also the pressure reading at idle (0..11 seconds, and 75..90) seconds is "too good". For the mileage I would have expected to see something closer 10 mbars for a DPF in normal condition.

Also a bit confusing is why the exhaust temperature at the exhaust manifold doesn't fluctuate at all - did the test actually fail to perform as designed = flat RPM = looks like the engine didn't get loaded at all thus flat temperatures. Which would render the "results" just into useless.

Anyways, really appreciate you doing the tests - obviouly there is still a lot to learn.



For comparison below

 

[John-K]

I have now cleaned the maf with maf cleaner, and the connector with el cleaner. I have also used starter fluid on the vacuum hoses and on the intake to try to find any air leak. The engine did not react while i was spraying around the engine. I tryed to disconnect the maf sensor while the engine was running and the engine reacted to that ,so mightbe the maf sensor is OK?
Should i mightbe retake the previous test now, after i have cleaned the maf sensor?
Is it an better way to locate any air leak beside using a smoke machine, wich i dont have

 

[mmi]

Should i mightbe retake the previous test now, after i have cleaned the maf sensor?

Yes, would be interesting to see if it's different now. Have you cleared engine fault codes before test?

Is it an better way to locate any air leak beside using a smoke machine, wich i dont have

Using starter fluid was a good one. Another way could be to try block intake airway somewhere before the MAF sensor.

 

[John-K]

Yes, would be interesting to see if it's different now. Have you cleared engine fault codes before test?


Using starter fluid was a good one. Another way could be to try block intake airway somewhere before the MAF sensor.

Here are a new test with all codes deleted. Today when i drove to work the dpf lamp appeared, but there wasn`t any error code on the dpf when i checked with the vcds

 

[mmi]

Here are a new test with all codes deleted.

Thank you. Unfortunately no different - I'm not sure what's going on. The MAF sensor readings are not what I would expect (much lower) but also the test doesn't do what I was expecting (slight up/down sweeps of RPM).






Obviously the engine was in the middle of DPF regeneration as the exhaust temperature after the DPF is so high (different temp scale in the graph than before).

Today when i drove to work the dpf lamp appeared, but there wasn`t any error code on the dpf when i checked with the vcds

The DPF lamp as such is not a fault - just an indication that soot (calculated) is significantly higher than a threshold to start normal DPF regen - and thus one should continue driving to get soot level down (till light turns off).

The blockmap data of this morning shows ongoing/activated regen and soot levels now well below the threshold. The "since" counters will reset when the regen is finished.

IDE00021	Engine speed	1012	/min
IDE00430	Particle filter: field regeneration request status	Request via soot loading model active
IDE00432	Particle filter: time since last regeneration	524	min
IDE00434	Particle filter: soot mass calculated	18.06	g
IDE00435	Particle filter: soot mass measured	0.79	g
IDE00436	Particle filter: kilometers since last regeneration	123.2

 

[John-K]

Thank you. Unfortunately no different - I'm not sure what's going on. The MAF sensor readings are not what I would expect (much lower) but also the test doesn't do what I was expecting (slight up/down sweeps of RPM).

View attachment 294943
View attachment 294944
View attachment 294945
View attachment 294946

Obviously the engine was in the middle of DPF regeneration as the exhaust temperature after the DPF is so high (different temp scale in the graph than before).
View attachment 294947


The DPF lamp as such is not a fault - just an indication that soot (calculated) is significantly higher than a threshold to start normal DPF regen - and thus one should continue driving to get soot level down (till light turns off).

The blockmap data of this morning shows ongoing/activated regen and soot levels now well below the threshold. The "since" counters will reset when the regen is finished.

IDE00021	Engine speed	1012	/min
IDE00430	Particle filter: field regeneration request status	Request via soot loading model active
IDE00432	Particle filter: time since last regeneration	524	min
IDE00434	Particle filter: soot mass calculated	18.06	g
IDE00435	Particle filter: soot mass measured	0.79	g
IDE00436	Particle filter: kilometers since last regeneration	123.2

Do you think i should buy a new maf sensor and see if that helps?

 

[mmi]

Do you think i should buy a new maf sensor and see if that helps?

That's what the fault code suggests - unless there is an air leak. Meanwhile you could make a recording of a normal journey so we could see if the MAF sensor reports clearly non-correct values.

Just to show what could be achieved by recording below an example of such a recording doing a slight incline (64 meters across 3.4 km at steady 80 km/h (cruise control assisted) - between the markers). For reference also the actual incline profile to better understand where engine gets more loading.

 

[John-K]

That's what the fault code suggests - unless there is an air leak. Meanwhile you could make a recording of a normal journey so we could see if the MAF sensor reports clearly non-correct values.

Just to show what could be achieved by recording below an example of such a recording doing a slight incline (64 meters across 3.4 km at steady 80 km/h (cruise control assisted) - between the markers). For reference also the actual incline profile to better understand where engine gets more loading.

View attachment 294950

View attachment 294952

This is getting weirder i think. A friend of mine has the same car so i drove to him now and put his sensor in my car, but after 2 minutes of driving the P0101 00 and P0402 00 code came back along with the flashing glow lamp.

This is getting weirder i think. A friend of mine has the same car so i drove to him now and put his sensor in my car, but after 2 minutes of driving the P0101 00 and P0402 00 code came back along with the flashing glow lamp.

Here is a test i did while driving

 

[mmi]

Indeed, the ECU doesn't agree what it sees from the sensor.

P0101

P0101 Mass Air Flow Sensor (G70)- Implausible Signal

A friend of mine has the same car so i drove to him now and put his sensor in my car, but after 2 minutes of driving the P0101 00 and P0402 00 code came back along with the flashing glow lamp.

So not likely the sensor then?
It seems that also at about 55 seconds the engine went into a kind of backup mode: closed the EGR (red curve). Probably because couldn't trust the air mass sensor. Probably the flashing glow lamp was turned on then?



PS. Vehicle speed is a useful to be recorded always as it gives good idea of engine load (accelerations, decelerations, engine load by air resistance at decent speeds (above 40 mph starts to be a significant factor)

 

[dino-bosnia]

Hello
I have just changed my egr valve (about 1000km since) and since that my glow plug lamp and engine lamp keeps flashing 1-3 times a day. What can be the problem?

Hi, in my case there was "insuficient flow egr", and B1S3- sensor temperature before DPF. Reason? Broken pipe for intercooler Probably, temperature sensor saw different value, not in expected interval, and everything because of less air and more fuel and after nore ash. When I change pipe, there is no more Glow plug light. I was in many service and all of them said that I have to change DPF, they didn't see broken pipe.

 

[John-K]

Hello
After my holiday i have started dealing with this damn car again.First thing i did was to take out the dpf and send it to be cleaned. The workshop that did it said they washed out 130 grams of sooth and ash. Yesterday i left the car at my local VW garage so they could take a look at it, and they suspect that it could be an injector that is leaking. They wanted to do a injector leak off test, but i had to wait 2 weeks before they had time to do it. I bought a set today and did it my self.3 of the glasses is kinda the same amount but 1 of them is a bit less. I ran the engine for about 2.5 min on idle when i did the test. Can anybody see out of the picture if any of my injectors is bad?

 

[mmi]

Workshop manual states:

• Return flow volumes between individual injectors may fluctuate within thresholds.
• Fuel volume in hose line must be taken account of during measurement.
• Specification of individual injector in mono-turbo and bi-turbo in 2 minutes: 0 … 25 ml

4-cylinder common rail engine CXEB CXFA CXGA CXGB CXHA CXGC CXHB

5 Feb 2023

CXEB CXFA CXGA CXGB CXHA CXGC CXHB

• Loz
• cxeb engine cxfa engine cxga engine cxgb engine cxgc engine cxha engine cxhb engine manual
• VW Manuals

Thread '[T6_measured] Injector failure'

24 Nov 2017

Keyword “loud knocking metallic noise from engine”. VW has published in September a service note which can be found with vehicle's VIN.

The sound clips from my engine (150PS, EU6) with comments on 21 Oct 2017 in thread Tick over noise
EDIT: audio files from the thread copied here as attachments- Also the extracted plots at end of this post.

At time of the recording van had 16.000 km, now 32.000 km.

According to VW procedure the first step was to pour VW fuel additive into the tank and fill it up. The additive is widely used setane booster (2-ethylhexyl nitrate) which makes fuel...

• mmi
• engine hydraulic tappets injectors knocking t6_measured
• Replies: 27
• Forum: Engine, Gearbox, Exhaust, Drivetrain

• 

 

[TheGrapeEscape]

I had the p0101 code pop up on mine. Just had my mate smoke test it, my intercooler is split below the grill