Where’s This Bit From? . . . . Tonight’s Quiz

Well, not exactly a bit, rather T6 diesel behaviour - every now and then.

T6. Engine hot. Starts when vehicle has reached standstill. Engine on tick-over - 830 RPM. Stop/start doesn't shut off the engine.

Sound clip attached - a "hiccup" regularly every 1.5 seconds. Can last up to two minutes. Recording made outside. Best heard on right side of vehicle (standing by right front wheel). Can be heard in cabin, too.
View attachment T6_CXEB_Hiccup_20181213.mp3
T6_CXEB_Hiccup_20181213.png
 
Well, not exactly a bit, rather T6 diesel behaviour - every now and then.

T6. Engine hot. Starts when vehicle has reached standstill. Engine on tick-over - 830 RPM. Stop/start doesn't shut off the engine.

Sound clip attached - a "hiccup" regularly every 1.5 seconds. Can last up to two minutes. Recording made outside. Best heard on right side of vehicle (standing by right front wheel). Can be heard in cabin, too.
View attachment 118644
View attachment 118631
Sounds like a pump or a PRV lifting?
 
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Where’s This Bit From? . . . . Tonight’s Quiz - 060621​


A,B,C,D - answers below -please.


A:
1622982073388.png

B:
1622982087496.png

C:
1622982102497.png

D:
1622982114721.png
 
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A. Little trap door in bumper that hsa an alien with a water pistol behind.
B. Part of the trim in the headlining with the mic behind? I cant check :/
C. Drain in bottom of tailgate.
D. Door catch
 
Well, not exactly a bit, rather T6 diesel behaviour - every now and then.

T6. Engine hot. Starts when vehicle has reached standstill. Engine on tick-over - 830 RPM. Stop/start doesn't shut off the engine.

Sound clip attached - a "hiccup" regularly every 1.5 seconds. Can last up to two minutes. Recording made outside. Best heard on right side of vehicle (standing by right front wheel). Can be heard in cabin, too.
View attachment 118644
View attachment 118631
Adblue pump pressure relief valve
 
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C is the cover for the screw to release the lock barrel on the front doors
 
A. Little trap door in bumper that hsa an alien with a water pistol behind.
B. Part of the trim in the headlining with the mic behind? I cant check :/
C. Drain in bottom of tailgate.
D. Door catch
Actually is D the barn-door catch?
 
I was guessing at that, as I've never really looked at one. Tailgates ftw lol.
Hah. I’ve had one, then the other, so should know! But as it was @Dellmassive’s van, which is BD, I thought it would be the better guess!
 
Well I can see the EGR valve is cycling for some reason at tickover, all other values on your display seem to correlate this.
From what I understand the EGR valve is motor driven so the noise is not from a vacuum valve
I give up on this one. 830RPM = 13.83 R/sec / 2 for 720 deg for injection at tick over = 6.91 secs. Not divisible by 1.5
 
I give up on this one. 830RPM = 13.83 R/sec / 2 for 720 deg for injection at tick over = 6.91 secs. Not divisible by 1.5
Thank you very much for the interest :thumbsup: Actually I don't have definite answer so explanations, opinions, ideas... all are welcome.

My thought about the phenomena is that the engine is doing a kind of EGR calibration. As the EGR cooler gradually gets clogged, EGR needs to be adjusted accordingly to maintain optimal combustion conditions.

Below a zoomed out version of the recording above - but just two parameters (EGR closure vs. air flow)

So basically EGR is kept closed 0% (no exhaust recirculation) for 2 seconds (') thus cylinders are filled with fresh air (approx. at rate 16.9 g/s). Then EGR is quickly opened (to 40%) which reduces the "fresh" airflow down to approx. 8.8 g/s.
(*) Actually EGR closuretime "slides" during the process from 1.5 to 2 seconds (as below). The sound clip was from a beginning.

1623092026095.png

The flat section on the right starting at 1585 seconds is where engine run returns back to normal.

To prove my theory we certainly should find a van having active fault P0401 - insufficient EGR flow detected.

Does this make any sense at all? If there is any interest for more I'll start a new thread.
 
Thank you very much for the interest :thumbsup: Actually I don't have definite answer so explanations, opinions, ideas... all are welcome.

My thought about the phenomena is that the engine is doing a kind of EGR calibration. As the EGR cooler gradually gets clogged, EGR needs to be adjusted accordingly to maintain optimal combustion conditions.

Below a zoomed out version of the recording above - but just two parameters (EGR closure vs. air flow)

So basically EGR is kept closed 0% (no exhaust recirculation) for 2 seconds (') thus cylinders are filled with fresh air (approx. at rate 16.9 g/s). Then EGR is quickly opened (to 40%) which reduces the "fresh" airflow down to approx. 8.8 g/s.
(*) Actually EGR closuretime "slides" during the process from 1.5 to 2 seconds (as below). The sound clip was from a beginning.

View attachment 118776

The flat section on the right starting at 1585 seconds is where engine run returns back to normal.

To prove my theory we certainly should find a van having active fault P0401 - insufficient EGR flow detected.

Does this make any sense at all? If there is any interest for more I'll start a new thread.
What takes priority optimal combustion monitored by the lambda sensor or optimal NO reduction monitored by the NOX sensor?
EGR system only degrades combustion as far as I’m aware.
 
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