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

[wannaT6]

Thanks mmi for the comprehensive plot of my vans data. Never had an EGR replacement since I've owned it (roughly 45k miles at purchase and have owned since 2019) It was never mentioned to me by the seller either who had a comprehensive list of work done. Hence thought EGR as sounds like a common issue at this mileage and with the symptons I had.

Scratching my head as to what's going on then. Every now and again (could go a few days) the engine has a little hiccup like it has a momentary dead spot and revs drop then picks up if I'm lucky. If unlucky then dead spot near stall/kangaroo will be much more severe and either drop into limp (flashing glow plug) or will stall. On restart it'll either start first time, or may have to wait a bit, perhaps like engine is flooded or some sort of component reset is required. Then after a wait of as little as a couple of minutes or up to an hour will turnover and run again. Left overnight the next morning will start without issue. Issue tends to happen in rev range of just below 2000rpm when have been cruising on the motorway slowly in 7th using cruise control, which seems to favour 1500 to 2000 revs (I have a dsg 4 motion). I was wondering if it might be EGR or related to DPF regen. But regens look like they are as normal and EGR seems ok alsoa after test. Camshaft position sensor has been replaced not so long ago as a fault was found on that, but before then it was happening already anyway and thought that might be the cause due to a VCDS error found. Cambelt change was like 2 years ago along with water pump. Sometimes with the near stall, if I can rev the engine up to like 3000 it feels like some sort of bloackage that can be cleared then it will settle down for a while until next stuck below 2000 rpm. Also almost always tends to be PM or evening on way home from work, about a 20-25 min each way with a majority on motorway.

I've attached the VCDS autoscan. No faults on the engine/gearbox are apparent, but then she hasn't played up for while. Any clues very gratefully received, e.g vcds test run suggestions. Tried a few basic VCDS tests around EGR and turbo and non created any errors. Have been running shell vpower diesel for a couple of tanks too, but before then fuel was standard diesel.

Will just have to drive it more and try to get some consistent way of reproducing the fault. May have a look in the airbox this afternoon for a quick check also. Other things I am considering are an injector, fuel pump etc... Fault seems so sporadic/incosistent that I don't have much to go on yet.
Thanks and best wishes.

 

[mmi]

drop into limp (flashing glow plug)

No faults recorded even then???

Every now and again (could go a few days) the engine has a little hiccup like it has a momentary dead spot and revs drop then picks up if I'm lucky. If unlucky then dead spot near stall/kangaroo will be much more severe and either drop into limp (flashing glow plug) or will stall.

There are similarities with the issue in the thread below -

204 DSG intermittent momentary power loss

Hi all, Desperately looking for some assistance! I have a 2018 204 DSG high line. Had it from 8k miles, now has 82k on the clock. I’ve done all of the servicing and maintenance on it as I’m very mechanically minded and my business is automotive electrical design. However, I have a fault that I...

www.t6forum.com

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Please post an engine blockmap data - preferably hot engine idling.

VCDS > Applications > Controller Channel Map​

[Single Controller Address - 01]​

[Measuring Values]​

[CSV file]​

The result file blockmap-01-... will be in folder C:\Ross-Tech\VCDS\Logs\...​

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vcds test run suggestions

Perhaps could try to trigger the issue by driving at rev range where the issue has occurred

VCDS > Engine > Advanced measurement values >Tick the following:

IDE00021 Engine RPM​

IDE00075 Vehicle speed​

IDE00347 Air mass: actual value​

IDE00352 Main injection: duration of activation​

IDE00589 Fuel pressure​

IDE04685 Setpoint generation interior torque​

IDE07375 Charge pressure before throttle valve: calculated actual value​

IDE07736 Turbocharg.2 compress.outlet: press.sensor 1 bank 1: raw value​

IDE07742 Cylinder head: pressure sensor 3 bank 1: raw value​

IDE07785 Turbine actuator 1 bank 1: posit.feedback - Actual value​

IDE07793 Turboc.1 turbin.bypass valve 1 B. 1: pos.feedback - Actual value​

IDE08138 Bypass valve for turboch 2 turbine inlet: activation​

IMPORTANT!!! (to get high data sampling rate)​

Tick "Group UDS requests" - by 7.​

Click Log - Start​

Drive around for some time (20+ minutes) - please hit the "Marker" button if the issue happens (helps to navigate to the area of interest)​

Stop logging etc.​

The logfile will be in folder C:\Ross-Tech\VCDS\Logs​

 

[wannaT6]

There are similarities with the issue in the thread below -

Thanks for the tip, haven't finished reading the thread you suggest but sounds very very much like my issue.

No faults recorded even then???

Didn't have vcds then and vehicle faults were cleared after I had camshaft sensor replaced.

Perhaps could try to trigger the issue by driving at rev range where the issue has occurred

Will run the test when I get some time and can get a co-pilot to click marker. Not tried any logging yet whislt driving so may take me some time to get right.

Thanks for the assist!

 

[wannaT6]

@mmi just looking at running test today if I can get it setup right. I managed to get an extract of the old logs before work was done and faults cleared.

I think the problem could be that I have had the wrong sensor replaced. Camshaft rather than crankshaft. The sensor that was replaced according to the mechanic was the one on the top of the engine but underneath the intercooler.

I think the error below is crankshaft which I think sits at the bottom/back of the engine near oil filter? Probably can get to it from underneath the vehicle. The mechanic that replaced teh sensor isn't familiar with VW vans so guessing that has played it's part.

13183 - Engine Speed Sensor (G28)
          P0321 00 [01100000] - Implausible Signal
          Intermittent - Not Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Priority: 2
                    Fault Frequency: 1
                    Mileage: 127513 km
                    Date: 2078.01.09
                    Time: 20:09:36

                    Engine RPM: 3966.00 /min
                    Normed load value: 0.0 %
                    Vehicle speed: 79 km/h
                    Coolant temperature: 89  C
                    Intake air temperature: 15  C
                    Ambient air pressure: 980 mbar
                    Voltage terminal 30: 14.234 V
                    Unlearning counter according OBD: 8
                    HWI_Aps_cam_index: 1
                    HWI_Aps_gap_period_detected: OFF
                    P_L_Aps_crank_event_num: 0E
                    IN_Injection_speed: 3966.00 /min

13184 - Engine Speed Sensor (G28)
          P0322 00 [01100000] - No Signal
          Intermittent - Not Confirmed - Tested Since Memory Clear

27292 - Crankshaft Position Sensor (G28)
          P0335 00 [01100000] - Malfunction
          Intermittent - Not Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Priority: 2
                    Fault Frequency: 1
                    Mileage: 127513 km
                    Date: 2078.01.09
                    Time: 20:09:36

                    Engine RPM: 3966.00 /min
                    Normed load value: 0.0 %
                    Vehicle speed: 79 km/h
                    Coolant temperature: 89  C
                    Intake air temperature: 15  C
                    Ambient air pressure: 980 mbar
                    Voltage terminal 30: 14.234 V
                    Unlearning counter according OBD: 8
                    HWI_Aps_cam_index: 1
                    HWI_Aps_gap_period_detected: OFF
                    P_L_Aps_crank_event_num: 0D
                    IN_Injection_speed: 3966.00 /min

27291 - Crankshaft Position Sensor (G28)
          P0335 00 [01100000] - Malfunction
          Intermittent - Not Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Priority: 2
                    Fault Frequency: 2
                    Mileage: 127512 km
                    Date: 2078.01.09
                    Time: 20:08:00

                    Engine RPM: 1582.25 /min
                    Normed load value: 0.0 %
                    Vehicle speed: 103 km/h
                    Coolant temperature: 90  C
                    Intake air temperature: 14  C
                    Ambient air pressure: 990 mbar
                    Voltage terminal 30: 14.281 V
                    Unlearning counter according OBD: 40
                    HWI_Aps_cam_index: 1
                    HWI_Aps_gap_period_detected: OFF
                    P_L_Aps_crank_event_num: 00
                    IN_Injection_speed: 1582.25 /min

 

[mmi]

I think the problem could be that I have had the wrong sensor replaced. Camshaft rather than crankshaft. The sensor that was replaced according to the mechanic was the one on the top of the engine but underneath the intercooler.

Yes, that's the camshaft sensor - location in the picture in the thread below

Won’t start. No fault codes

Thank you very much Catfood12 I will certainly do that tomorrow and let you guys know how we get on I don't think you'll see anything, as the injection duration is at zero. When you said earlier it starts and runs on Easy Start, do you mean you have to keep feeding on Easy Start to keep it...

www.t6forum.com

27291 - Crankshaft Position Sensor (G28)
P0335 00 [01100000] - Malfunction

Definitely needs to be replaced.

Will run the test when I get some time and can get a co-pilot to click marker. Not tried any logging yet whislt driving so may take me some time to get right.

Definitely interested to see how the data looks - from a failing sensor

 

[wannaT6]

OK, had a go at getting her to fault and she was being obstinate, as per the other thread, no apparent issues this drive.
I've attached my test run/block data/test fields setup, for future reference, will hopefully get a chance to try again tomorrow.
Could be weather dependent, could just be me, but I think tends to happen more in the wet, worries me that it might be wiring to the sensor.
Tonight was cold and frosty, hasn't rained for a while.

 

[mmi]

OK, had a go at getting her to fault and she was being obstinate, as per the other thread, no apparent issues this drive.
I've attached my test run/block data/test fields setup, for future reference, will hopefully get a chance to try again tomorrow.
Could be weather dependent, could just be me, but I think tends to happen more in the wet, worries me that it might be wiring to the sensor.
Tonight was cold and frosty, hasn't rained for a while.

Yes, nothing obvious sticking out from the data.
Some jittering can be seen in RPM data here and there but not in that scale what was seen in the thread:

204 DSG intermittent momentary power loss

If you floor it in neutral, the engine won’t spin up as quickly as that so it definitely cannot do it under partial/full load. Correct. But if you think the case of accelerating, pedal at 80% or so, rpm is limited and resisted by the torque through gearbox and ultimately grip on the road...

www.t6forum.com

EDIT: picture edited to better show the jitter

 

[wannaT6]

Yes, nothing obvious sticking out from the data.
Some jittering can be seen in RPM data here and there but not in that scale what was seen in the thread:

204 DSG intermittent momentary power loss

If you floor it in neutral, the engine won’t spin up as quickly as that so it definitely cannot do it under partial/full load. Correct. But if you think the case of accelerating, pedal at 80% or so, rpm is limited and resisted by the torque through gearbox and ultimately grip on the road...

www.t6forum.com

View attachment 221518

forgot to disable auto start/stop which was cause of this drop, so you can ignore that

 

[mmi]

forgot to disable auto start/stop which was cause of this drop, so you can ignore that

Thanks. Sorry about being a bit vague. Edited the picture to better show the "jitter" with a lot of smooth curve for comparison. Also the engine actually didn't stop then - the picture scaling is 900 - 2500 RPM

 

[wannaT6]

No worries. Sorry it's taken a while, shes been obstinate, only playing up and glitching on the revs/fueling when I've not been recording, but finally caught one on VCDS logs on the way home from work today.

Didn't manage to click Marker until a bit after it happened so check about 5-10 secs before the single marker.
Will keep logging in the hope of getting a larger series of them. Can be very random as to when it happens.

 

[mmi]

Ok - thanks. The marker was at 660 seconds. The plots below are 20 seconds before.

Engine speed sensor​

So nothing special - no sudden jump in engine RPM. However, it seems that the important bit of setting high data sampling rate was forgotten - the samples are 1.2 seconds apart (see the dots). The glitches recorded in the other thread lasted typically only 0.3 seconds so I think chances are we might have missed the possible glitch in between samples?

IMPORTANT!!! (to get high data sampling rate)
Tick "Group UDS requests" - by 7.

Engine torque etc.​

There are a few significant changes in engine torque but they last quite long so more likely induced naturally by throttle input. Also other parameters align with the torque and cylinder pressure (charge pressure, fuel injection, fuel pressure).

 

[wannaT6]

ah your right, my bad. sorry forgot the group uds requests! was in too much of a hurry to get home. will try again today

 

[wannaT6]

ok got one on the drive in this morning. just before the marker sometime in teh 5 sec range, just a small stutter and just the one that I noticed. Will post another from drive home later.

 

[Skyliner33]

Just come across this thread. Do you need any more. Mine is a 6.1 150hp.

 

[mmi]

ok got one on the drive in this morning. just before the marker sometime in teh 5 sec range, just a small stutter and just the one that I noticed. Will post another from drive home later.

Hmmm... the file is empty?

 

[mmi]

Just come across this thread. Do you need any more. Mine is a 6.1 150hp.

Yes please

 

[wannaT6]

Hmmm... the file is empty?

Apologies. Not sure what happened there> ran another on the way home with 1 glitch which took me a little while to click the marker on so check back like 10seconds

 

[mmi]

ran another on the way home with 1 glitch which took me a little while to click the marker on so check back like 10seconds

Thanks. The marker was at 685 seconds - a noticeable glitch was 23 seconds!? before - at 662 seconds - lasted for 0.3 seconds (the spike upwards in engine RPM - orange below). It's seen also as spiking in fuel pressure.

I guess the big dip downwards at 665 seconds is because of DSG coasting perhaps (torque=0)??? Also seems that there was a gear change up then.

 

[wannaT6]

Thanks for that. yes could have been as long as 23 secs from the marker, was a fair bit of traffic and had no copilot. suspect 665 big drop is the glitch. was fairly noticeable but quick. was just cruising somewhere around 70 on m3 in auto, i didnt notice a downshift just the engine stutter, but wasn't directly looking at the instruments at that time to see if there was a quick down/upshift on the glitch, so cant be 100% sure. perhaps next time will drive in manual, but then glitch is harder to reproduce as i tend to have the revs higher.

 

[wannaT6]

Have done another run. Just one glitch, managed to press marker button not long after.
Cruising on motorway at about 70 in 7th Manual, so hoping results should be clearer, revs should have been fairly consistent around the 2000ish mark.
Tomrrow changing the crankshaft position sensor so will try and do one after sensor change.