Since many garages I visited can't figure out my problem I'm turning to this specialist forum in hope you can help me out.
My casus is about my VW Transporter (2010) 2.0 TDI CR with engine code CAAC. The car was bought 1,5 year ago with 56K and has now 95K km.
The problem is that my car seems to be very outside temperature sensitive. The engine always starts very easy but with higher outside temperatures starts to run rough and noisy and eventually with real high outside temps even starts to misfire.
In the temperature range of 5 degree celcius to 9 degrees celcius the car operates really smooth and has lots of power.
But when the temperatures get above 10 degrees the car starts to run rougher and rougher. With temps above 17 degrees the car starts to make erratic injector noises when you ask torque from the engine by pushing the gas paddle. The engine then seems to have no torque at all under 2000 RPM and starts to shudder when you drive the car under 2100 rpm in 5th gear.
With temperatures above 25 degrees the injectors start to make really a lot of noise and eventually the engine starts to misfire with bad knocking sounds. I'm not really sure if what I call injector sound is not misfiring that starts as ticking sound and eventually with real high outside temperatures becomes knocking.
What has been replaced the last 1,5 year :
-EGR-valve was broken by a short circuit because of condense caused by exhaust gasses.
-2 MAF sensors (just to eliminate)
-MAP sensor (just to eliminate)
-Rail Pressure sensor (just to eliminate)
-4 injectors (were out of range) strange with such a young engine
-Dual mass flywheel was not broken but bad
What has been checked the last 1,5 year :
-Timing has been checked two times
Multiple garages have had my car on the VAGCOM computer but the car doesn't show any DTC Fault codes!
Eventually I bought my own VAGCOM cable to put more energy in my problem. I have checked all temperatures of all sensors with cold engine and they are then all the same as the outside temperature. When the engine warms up I don't get any strange readings.
-Outside temperature normal
-Fuel temperature normal
-Air intake temperature normal
-Cooling liquid before and after radiator normal
-Air temps after turbo and after intercooler normal
I have checked all fuel pressures and VCDS doesn't give any strange readings between the relative and absolute pressures.
The only thing at this moment I can think of is a bad rail fuel pressure valve or a bad IMV on the fuel pump but I can't see the correlation between outside temperature and a faulty fuel pressure valve or bad IMV. I read more than thousand topics in numerous forums but can't find anybody with exact the same problems I have!
I really hope one of you can help me out with a brilliant Idee or that somebody has encountered this problem before!!
Kind regards Bram
The Netherlands
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Last edited by BB-4motion on Thu Feb 22, 2018 7:09 pm, edited 1 time in total.
That's a tough challenge you are facing. Let me start by saying that I've have no solution to your problem - whatsoever.
My first question will be - do you intend to diagnose this problem yourself ?
My second question is - what diagnostic tools do you have availble besides the VCDS software ?
The VCDS software is one of the best tools to diagnose VAG cars, but one should remember that the data values your are looking at the VCDS software are not live data as opposed to the Picoscope where your are measuring at the sensor itself.
So VCDS software is a good tool, but you dont get the details as in a Picoscope.
I´ve some theorys, but a theory alone does not solve a problem alone - the theory has to be physical tested on the car to get some diagnostic direction.
It's possible for me to make a vcds scan of my car.
But Let me know what channels you want to see under what conditions.
Only thing that is not possible is to do this with temps above 17 degrees, because it's wintertime here and I was not planning to drive to spain at this moment.
Kim if you have also any suggestions in which direction I could take a look please Let me know. I can post live data from Vcds.
Hi, if you connect VCDS to your data port and complete an auto scan then VCDS will search all modules fitted and display all data available, then we can look through it and see if anything stands out!
Bram, if you need pico diagnostics, I have my scope here, close by Rotterdam.
I have 0 knowledge of VW. Any way to fool temp sensor to see if this is control issue or just a real mechanical issue?
I made an Auto Scan and two different .csv logs today. One CSV is only temperatures started with cold engine and drove till it was warmed up.The second .csv is with some pressures air and fuel and injection deviation which some deviaton between cilinder two and four when you ask torque from the engine.
Monday,19,February,2018,15:02:58:04550
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 10 x64
VCDS Version: 15.7.0.2
Data version: 20150820 http://www.Ross-Tech.com
It takes some time to interpretat those VCDS log file you have taken.I´ve seen both log files and particular the last PICO Log file are interesting to study in details. There are a couple things that dont look right and here I´m talking about actual value versus specified values in the higher region.
Transporter 03L906022CJ R4 2.0L EDC
Here I´ve loaded the Pico_Log file into VCDSVIEW program and seen at the two cursors which I´ve placed one in the upper region of the data value field and the other in the lower region is it clear that there is a mismatch between actual and specified in the air mass field - charge air mass field and also fuel pressure data values are sometimes showing the wrong values.
The first advise I would give were to measure the air mass sensor output voltage with a oscilloscope or make a new VCDS log file where you log the raw data value from the air mass sensor in millivolt.
Hi Kim! First I would like to mention that it's fantastic that you are willing to put some time and afford in my problem!!
I indeed forgot to mention that the car is tuned by JD-engineering in the Netherlands. They say he is one of the best VAG-tuners in the Netherlands. The Tuning has been done in hope that this would solve my problems. Actually the car has more torque so it runsa bit better in the low regions of RPM.
But the actual problem of temperature sensitivity never disappeared. They also ran the car on the Dyno and it's very clear that the car developes it's power after 2000 rpm but it reaches the standards of the tuner with full throttle.
I checked more dynoruns from other tuners with similar engines on internet and I can see there that the torque is rising much earlier. I will try to upload the diagram later!
If I can make a specific run with specified measuring blocks for you please let me know! I will make a run of raw data and post it also!!
What do you think of the injector deviation between cilinder 2 and 4 when I ask torque from the car?