Lumpy engine start and idle
- Thread starter shaiboyuk
- Start date
Thanks, the three minutes is just to capture full glow plug post-heat period (two minutes) + a minute of running without glow plugs. The log was about 4 minutes - just perfect!Morning,
5 degrees here, started and lumpy
Ran the recording, but don't think I got the full 3 mins :/. (tried to set a timer in google and didn't start DOH!)
Tried to do it again, but by this point the engine was running better already :/
Let me know if its ok
Thanks again for your help.
Indeed the engine is running poorly. The charts below are 30 seconds each, thus 0...120 second depicteds. See a comparison chart further down.
Interestingly one could imagine that at 120 seconds from startup the deviation of injection duration gets larger? (different time scale to show more)
So perhaps the glow plug post-heating even stabilises running a bit?
So perhaps the glow plug post-heating even stabilises running a bit?
For comparison a healthy idling:
I think the takeaway is that ECU is trying to stabilise the idling RPM by alternating injecting extra dose of fuel (longer injection duration) and then injecting less.
All the other parameters seem to just consequences of the lumpy running.
For normal run the injection variation is within 100 microseconds but now the variation is 4-5 times larger.
Quite similar what was seen in thread below
Lumpy T6 - Triggers Broom! Misfire & Vibration under 1500rpm.
Hi All, I have a 2018 T6, that I'm running out of patience with... and garages... So I have purchased VCDS to try and get to the bottom of it... First issue was it started to use coolant, I swapped a known good charge cooler to eliminate that, Max to min in around 100 miles, So took it to VW...
Any loss of coolant?
Thanks sir, a lot of info there, don't know what to make of it 
No loss of coolant
Oil has some condensation but normal for short journeys
Anything else I can do or need to wait for garage and hope they can find the cause ... :/
Thanks for all your help
No loss of coolant
Oil has some condensation but normal for short journeys
Anything else I can do or need to wait for garage and hope they can find the cause ... :/
Thanks for all your help
Difficult to say anything definite. Good thing is that the issue can be seen clearly in the data - but what's causing it is a challenge. I'm fairly confident it's an issue with a cylinder (of four). Possibly an injector is playing up. Probably need to start from basics - compression test, etc.Thanks sir, a lot of info there, don't know what to make of it
That's a good thing!
Well, I was hoping the recorded injection speed by cylinders would help to pinpoint which cylinder is the imbalanced one but I'm not exactly sure how to interpret small variances between cylinders.
So if you could make a new recording but using the data items below - interested to see if there is a correlation between these and if something sticks out. Again preferably a lumpy running - 3 minutes.
IDE09327 Cylinder 1 bank 1 internal moment
IDE09328 Cylinder 2 bank 1 internal moment
IDE09329 Cylinder 3 bank 1 internal moment
IDE09330 Cylinder 4 bank 1 internal moment
IDE12085 Fuel injection time deviation: cylinder 1
IDE12086 Fuel injection time deviation: cylinder 2
IDE12087 Fuel injection time deviation: cylinder 3
IDE12088 Fuel injection time deviation: cylinder 4
ENG126008 IN_Injection_speed_injector[0]
ENG126009 IN_Injection_speed_injector[1]
ENG126010 IN_Injection_speed_injector[2]
ENG128778 IN_Injection_speed_injector[3]
Meanwhile, some thoughts based on the existing recording.
The four data items "IN_Injection_speed_injector" 0, 1 ,2, 3 possibly could be RPM seen (by ECU) between firing cylinders, thus a lower value would indicate that a cylinder doesn't provide as much "boost" as the others. Based on this assumption some calculations on the data.
In the first table all cylinders averaged individually, and then their delta on overall average RPM calculated of all cylinders.
The second table has deltas from a cylinder to the next in the firing order. E.g. Cyls. 3-4 = (2.79-(-2.85)) = 5.64
For comparison the same from my engine.
The average RPM is lower because the recording was started well before engine was started, thus plenty of 0 RPM in the log lowering the average.
The actual average engine idling is 827 RPM.
The average RPM is lower because the recording was started well before engine was started, thus plenty of 0 RPM in the log lowering the average.
The actual average engine idling is 827 RPM.
Oh no, sounds expensive :/
Thanks sir, will do this first thing tomorrow, so its nice and lumpy again
One thing though, when I turn the IGN on and take my time to tick all items then go to start engine, it takes 4-5 turns of starter to start, like its flooded with fuel. is this normal?
If I turn IGN on, and start right away, its starts first turn. Noticed this before, months ago, if IGN left on for a while then try to start its struggles.
Thanks again for all your help, don't fully know what i'm looking at but helpfull to know its showing something.
Let's hope the garage have the experience and can nail it down right away.
It's normal as the glow plugs did their pre-heat when ignition was turned on, thus the plugs are already cooled down. Well, I just wanted to capture also the cranking (and thus make it last a bit longer
).Anyways, to avoid the long cranking with VCDS - when you have ticked all the items - turn ignition off and immediately back on and to start - this way the glow plugs do their heat up and engine starts right away.
VCDS (or actually ECU) will stay alive during this short ignition off period. Actually ECU stays alive a few seconds after turning ignition off.
Thank you for making the logs. They are very helpful - as I can compare them with (still) properly working engine - to understand what to look for.
Thanks, and if it's not too much trouble could you also make a recording when it's running smoothly - for comparisonThanks sir, will do this first thing tomorrow, so its nice and lumpy again
Heres hoping, VW garage, so will see....
Perfect that will help thanks
Thanks, and if it's not too much trouble could you also make a recording when it's running smoothly - for comparison
No worries, with the same options ticked? (IDE09327 Cylinder 1 bank 1 internal moment... etc)? and just idling or driving?
Thanks. Just idling - it's easier to compare.
IDE09327 Cylinder 1 bank 1 internal moment
IDE09328 Cylinder 2 bank 1 internal moment
IDE09329 Cylinder 3 bank 1 internal moment
IDE09330 Cylinder 4 bank 1 internal moment
IDE12085 Fuel injection time deviation: cylinder 1
IDE12086 Fuel injection time deviation: cylinder 2
IDE12087 Fuel injection time deviation: cylinder 3
IDE12088 Fuel injection time deviation: cylinder 4
ENG126008 IN_Injection_speed_injector[0]
ENG126009 IN_Injection_speed_injector[1]
ENG126010 IN_Injection_speed_injector[2]
ENG128778 IN_Injection_speed_injector[3]
Ok, done a number of recordings (attached), as I know you love the data explained below
Log-02
IDE09327, IDE09328, IDE09329, IDE09330 etc
IGN ON, then cold start (5 degrees)
Lumpy :/
Log-03
IDE09327, IDE09328, IDE09329, IDE09330 etc
Durning my drive to clear lumpiness, the DPF started doing a regen, and the idle and acceleration felt more lumpy. So pulled over and done this log, unsure if it will show anything, maybe I should have done IDE00083 etc recording instead.
Log-04
IDE09327, IDE09328, IDE09329, IDE09330 etc
IGN ON, then start after long drive (Regen finished by this point)
Felt smooth now
Log-05
IDE00083, IDE00347, IDE00351, IDE00352 etc
IGN ON, then start after long drive
As had lumpiness when DPF kicked in earlier in drive, thought I would rerun the first recording from the other day
----
With the lumpiness when DPF started regen, could this point to issue with DPF or the EGR etc? Or even timing being out? :/
Got van booked into a VW garage next Monday, should I just let them troubleshoot from start, or let them know any info here? They don't have any courtesy vehicals, so I'm hoping its not in for long :/
Thanks again @mmi
explained below Log-02
IDE09327, IDE09328, IDE09329, IDE09330 etc
IGN ON, then cold start (5 degrees)
Lumpy :/
Log-03
IDE09327, IDE09328, IDE09329, IDE09330 etc
Durning my drive to clear lumpiness, the DPF started doing a regen, and the idle and acceleration felt more lumpy. So pulled over and done this log, unsure if it will show anything, maybe I should have done IDE00083 etc recording instead.
Log-04
IDE09327, IDE09328, IDE09329, IDE09330 etc
IGN ON, then start after long drive (Regen finished by this point)
Felt smooth now
Log-05
IDE00083, IDE00347, IDE00351, IDE00352 etc
IGN ON, then start after long drive
As had lumpiness when DPF kicked in earlier in drive, thought I would rerun the first recording from the other day
----
With the lumpiness when DPF started regen, could this point to issue with DPF or the EGR etc? Or even timing being out? :/
Got van booked into a VW garage next Monday, should I just let them troubleshoot from start, or let them know any info here? They don't have any courtesy vehicals, so I'm hoping its not in for long :/
Thanks again @mmi
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Your symptoms sound identical to what my van suffered last year. End result was filings through the fuel system, I really hope it ain't that, but all sounds very familiar
fillings through the fuel system???
just googled this, this seems to only happen with misfuelling, and causes engine to stall. defo not been misfuelled and engine runs fine once it get past initial lumpiness
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That's caused by the HPFP failing. (The metal in the fuel)
That normally needs a.new HPFP. New injectors. And a full tank and system flush.
Definitely an expensive job.
That normally needs a.new HPFP. New injectors. And a full tank and system flush.
Definitely an expensive job.
But this can't be whats happened to mine, why would it run fine after initial lumpiness? surely it would cause more issues as the RPM increased?
would this be covered under extended warranty? as the pump is after the filter, nothing to stop it?
Thanks
Thank goodness
Well ruled that out
Maybe, maybe not. Mine did result in non start as it broke down, but lumpy idle during cold starts and regen is how it all began followed by an injector deviation fault. After I replaced the injector all was great for 150 mile.
Remember that a cold engine at idle the injectors are working hard to keep smooth running etc so will highlight any weaknesses easier.
Yes, misfuel can cause the pump to go which mine may have had, I don't know as I ain't had it from new.
Thank you very much. Below just first impressions as didn't have much time to look into.Ok, done a number of recordings (attached), as I know you love the data
Cylinder 1 data
Cylinder 2 data
Cylinder 3 data
Cylinder 4 data - interestingly the first 20 seconds are quite different. Does the "loss" of torque mean that engine was almost running only on three cylinders?
Cylinder 1
Cylinder 2
Cylinder 3
Cylinder 4 - nice and smooth...
Once ticked you can save them into a file - and next time use that file to load the items in one go.
Based on the blockmap data item below - no.
IDE00182 Camshaft adaptation intake bank 1: phase position = 1.2 °
Not likely. However, the blockmap data shows there is a significant soot "stress" on the DPF but manageable this far.
The "soot measured" is normally lower than "soot calculated"
IDE00434 Particle filter: soot mass calculated = 15.22
IDE00435 Particle filter: soot mass measured = 18.16
As soon as the lumpiness has been resolved we could take a closer look on thisEGR cooler and DPF can be tested as below
[T6_measured] 01-Engine - Built-in test for EGR
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 -...
EGR valve can be tested as below
EGR Valve Self Test Procedure (IDE00242)- P046C?
So, I've been getting the all too common P046C fault code along with P2457 (Insufficient EGR Cooling Performance). Neither alone will flag a check engine light but combined they sometimes seem to. To try to figure out what is going on, I ran an EGR Flow test on VCDS using instruction from @mmi...
Well, could be a timesaver if they are willing to listen customer
I would show the pictures from post #37.I believe the injector return flow test might be the way forward - see below
[T6_measured] Injector failure
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...
Also the thread below worth to read
VW T6 (2018 cxha) - mystery engine jerks and judders av 2-3k rpm problems
Hi T6 forum, Hello from . (New to this forum, but done countless hours of searching for simular problems.) I'm calling out for some help/advice with our engine problem. Long story short(ish).. We bought a "project" car with broken timing belt (toothed belt). Belt was split, but not broken...
Sorry for delay replying, been a busy couple of days.
Perfect, I thought there would be a way to save it, but couldn't find it at time. thanks sir.
1.2 ° is ok then?
Need to be cleaned or cleaner through it? or a different type of regen?
I will print the graphs from post #37 and give it to them, fingers crossed, but believe VW Techs have to follow there own routes, but hopefully will save time and money
So my thinking from tests and the data is that the issue is with cylinder 4/injector 4, because it not working fully at start, its throwing the ECU out and that makes the other cylinders/injectors work hard throwing them out too, until cylinder 4 comes back then they all run correctly.
This is what i'm hoping and injector being replaced fixes it.....
Perfect, I thought there would be a way to save it, but couldn't find it at time. thanks sir.
1.2 ° is ok then?
Need to be cleaned or cleaner through it? or a different type of regen?
Well, could be a timesaver if they are willing to listen customer
I believe the injector return flow test might be the way forward - see below
[T6_measured] Injector failure
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...www.t6forum.com
I will print the graphs from post #37 and give it to them, fingers crossed, but believe VW Techs have to follow there own routes, but hopefully will save time and money
Also the thread below worth to read
VW T6 (2018 cxha) - mystery engine jerks and judders av 2-3k rpm problems
Hi T6 forum, Hello from . (New to this forum, but done countless hours of searching for simular problems.) I'm calling out for some help/advice with our engine problem. Long story short(ish).. We bought a "project" car with broken timing belt (toothed belt). Belt was split, but not broken...
So my thinking from tests and the data is that the issue is with cylinder 4/injector 4, because it not working fully at start, its throwing the ECU out and that makes the other cylinders/injectors work hard throwing them out too, until cylinder 4 comes back then they all run correctly.
This is what i'm hoping and injector being replaced fixes it.....
