204 DSG intermittent momentary power loss

[Dellmassive]

Might be worth data logging the fuel rail pressure to see if the correlates to any drop in power?

Have you got a obd2 dongle?

TORQUE App is very good for live data..


I use the Carista Evo dongle..... Gen 1 dongle works as well.

 

[Dellmassive]

Might be worth data logging the fuel rail pressure to see if the correlates to any drop in power?

Have you got a obd2 dongle?

TORQUE App is very good for live data..

See here...

 

[Dellmassive]

And @mmi might be able to look at the vcds data when he gets a chance.

 

[Cog Head]

I've had a Quick Look at the data from VCDS, it looks like the "Turboc.1 turbin.bypass valve 1 B. 1: pos.feedback - Actual value" drops off from 100% to 5-6% then rapidly builds again rite around when I hit the mark button, both turbo pressures and charge pressure match all the way through the rev range, the fuel pressure is stable, I'm really hoping this is a boost solenoid / valve / actuator issue

 

[Cog Head]

So, it looks like I either have a N75 valve failure, or there’s a split / leak somewhere in the valve lines associated with the valve assembly on the underside of the bulkhead.

The three little air filters are as black as the night sky too, so they’ll be replace regardless.

Before I rush off and buy a set of valves and a bucket of vac lines, I’ll wait in the hope that the grandmaster @mmi can interrogate the data properly to backup my thoughts.

 

[Dellmassive]

Is yours biturbo or single turbo?

There are one or three valves under the bonnet at the top of the engine bay.

edit:

3 on the Bi turbo and 1 on the single.

 

[mmi]

The logs are attached for the datapoints requested on page 1

hope that the grandmaster @mmi can interrogate the data properly to backup my thoughts.

I'm afraid the logs were lost. The attachment is just engine's adaptation map - almost 18 months ago

 

[Cog Head]

It’s a 2017 204 DSG twin turbo CXEB engine
I can only see the three valves, where will the other two be hiding?

I think I’ve uploaded the wrong file, bare with, I should be able to get it on my phone to upload

 

[mmi]

I can only see the three valves, where will the other two be hiding?

That's all for bi-turbo: 1) turbine vane actuator 2) turbine changeover 3) wastegate actuator
For single turbo there is only one valve - turbine vane actuator.

 

[Cog Head]

Awesome info, thank you.

I can’t get the log data from my phone, once I’m home I’ll upload it again.

So, which one of the three relates to “Turboc.1 turbin.bypass valve 1 B. 1: pos.feedback - Actual value”?

Do you know of the part numbers for the 3 little air filters? I can’t find them anywhere.

 

[Dellmassive]

That's all for bi-turbo: 1) turbine vane actuator 2) turbine changeover 3) wastegate actuator
For single turbo there is only one valve - turbine vane actuator.

Sweet, there we go.

3 on the Bi turbo and 1 on the single.

Thanks @mmi

 

[mmi]

So, which one of the three relates to “Turboc.1 turbin.bypass valve 1 B. 1: pos.feedback - Actual value”?

That's about turbine changeover valve/actuator.

Do you know of the part numbers for the 3 little air filters? I can’t find them anywhere.

7H0 129 965

---

I'd like to see engine blockmap files

1) Ignition ON, engine OFF
2) Engine idling

Also full VCDS Auto-Scan is more than useful.

---

How-to - create engine blockmap files

VCDS > Applications > Controller Channel Map >

[ Single controller address - 01 ]
[ Login or security access code - Leave empty ]
[ Function - Measuring values ]
[ Output - CSV file ]
Go

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

Note: only VCDS HEX-V2 and VCDS HEX-NET cables have the capability to create blockmap files.

---

The ECU has a couple of dedicated tests for turbocharger

The most relevant would be these two below (in posts 1 & 6).

Thread '[T6_measured] 01-Engine - Built-in tests for turbocharger'

13 Oct 2024

01-Engine - Basic Settings​

IDE00457-Test of turbocharger​

HOW-TO​

Engine running​

VCDS > Select > Engine > Basic Settings > IDE00457-Test of turbocharger​

Select "Measuring Values" ​

Pick up e.g. the following data items for monitoring:

IDE00021 Engine RPM​

IDE07736 Turbocharg.2 compress.outlet: press.sensor 1 bank 1: raw value (bi-turbo only)​

IDE07738 Charge air cooler inlet: pressure sensor 1 bank 1: raw value​

IDE07783 Turbine actuator 1 bank 1: posit.feedback - Raw voltage​

IDE07784...​

• mmi
• t6_measured turbo vcds
• Replies: 8
• Forum: Engine, Gearbox, Exhaust, Drivetrain

• 
• 

Post in thread '[T6_measured] 01-Engine - Built-in tests for turbocharger'

13 Oct 2024

01-Engine - Output Tests​

IDE00237-Turbocharger recirculation valve (only Bi-Turbo)​

HOW-TO​

Engine running​

VCDS > Select > Engine > Output Tests > IDE00237-Turbocharger recirculation valve​

Select "Measuring Values" ​

Pick up e.g. the following data items for monitoring:

IDE00021 Engine RPM
IDE07736 Turbocharg.2 compress.outlet: press.sensor 1 bank 1: raw value
IDE07738 Charge air cooler inlet: pressure sensor 1 bank 1: raw value
IDE07783 Turbine actuator 1 bank 1: posit.feedback - Raw voltage
IDE07790 Bypass...

• mmi

 

[Cog Head]

log files from earlier

 

[mmi]

First impression:
Any chance the engine has been remapped as seems to generate quite high charge pressure?
The actuators seem to travel their full operating range (just simply finding minimums and maximums).

 

[Cog Head]

It has been remapped, though I don't think it was a very good one.
im currently in the van doing the auto scan and block file

 

[Cog Head]

block map is attached

 

[Cog Head]

turbo test

 

[Cog Head]

turbo output test

 

[mmi]

block map is attached

Thanks. However, the blockmap ignition ON, engine OFF is missing. It's useful as it shows sensors, actuators, etc. in their "rest" positions.

turbo test

turbo output test

It seems that possibly was forgotten to "activate" data LOGging during the tests. Perhaps just "Save" instead of "Log" was clicked as there is only 1 datapoint in the files.

---

Well, looking into the blockmap data I'd like to see a log file of EGR test - both about cold engine and hot engine (after a minimum of 15 minute drive).

I'd like to verify degree of blockage of the DPF - based on the blockmap data engine idling the pressure loss (differential pressure) across the DPF is fairly high. Also the blockmap engine off would help determine any offset in the reading. The degree of blockage is just a by-product of the EGR-test because the test provides a nice way to control engine air intake.

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: 83
• Forum: Engine, Gearbox, Exhaust, Drivetrain

• 

 

[Cog Head]

oh, ok, im a complete newb to logging and what not, ill have another go today.
do I need to drive the van for each log to be saved?