2.0 FSI Poor idle when cold

[maro]

When you unplugged all of the sensors and tested, did you also unplug the intake flap actuator?

Oh no, flap motor with connector is buried deep below intake manifold. It is not easily accessible area.

Finding 1
Last weekend i unplugged cam adjustment solenoid (N205). It was funny to watch that commanded cam angle was fluctuating but actual was floating around +30 crank angle which should be mechanical lock to the most retarded position.
However car's behaviour persisted - high torque from cold engine to hesitation when hot. Maybe the knock control was enforced with intake flaps or base ignition timing??

Finding 2
Full tank of higher octane fuel 95->98 worked like a magic. Throttle response improved a lot. I have never seen such improvement even with 100 octane fuel taken from other petrol station. The change was literally instant within 1 tank and ~ 300 km driven. Cam adjustment during WOT stayed on -2,5. I learned on 95 octane that it dropped to -11 when there was going to be throttle lag. I guess intake valves stayed open awhile during compression stroke, deliberately ruining compression in cylinder = reducing power = protecting A/F mix from pre ignition?!

What version of Windows are you using with MPPS v16? I have a working software for it that works well on Windows 7/XP if you PM me.

It was WXP in VirtualBox and W10. App was loaded through ugly loader. I read that version without loader should work better. I will PM you.

I can confirm Kessv2 works perfectly too, in fact on my MED9.5.10 it writes in about 16 minutes vs the 38 minutes the MPPS v16 does. However both work pretty well on this setup for me


I managed to get my 1.6 FSI to 97kw (130whp) on my dyno through decat, intake, cam timing changes and making it run a LOT richer than VW did from factory, and putting more timing in. My stock tune would do what yours was doing and pull a load of timing, now I just get timing pull at low RPM but nothing I can do can help that with this high-compression engine.

That are some great news to hear. Needless to say i am shi**ing my pants when it comes to Chinese flash tool touching my ECU. I suppose we are not talking about genuine products.

[drbluetongue]

>I guess intake valves stayed open awhile during compression stroke, deliberately ruining compression in cylinder = reducing power = protecting A/F mix from pre ignition?!


Bingo

>However car's behaviour persisted - high torque from cold engine to hesitation when hot. Maybe the knock control was enforced with intake flaps or base ignition timing??

The intake flaps stay closed until the engine coolant hits a set temperature - mine was set to 75C. Check the LBKSOL section of the FR for details on how it works, particularly FMILBNMKR:

Flaps switching based on torque when cold (Moment zur Umschaltung der LBK Abh¨angig von Drehzahl bei kalter Motor)

On the 2.0 FSI, is the position sensor for the flaps buried as well?

[maro]

On the 2.0 FSI, is the position sensor for the flaps buried as well?

I peeked into workshop manual for 1.6 85kW FSI. Your upper & lower intake manifold has different shape. Also the flaps are actuated by vacuum and dreaded plastic rod which loves to break. Feedback is done via potentiometer that is mechanically attached to the flaps shaft.

2.0 FSI has adjustable manifold length runners, which is actuated by vacuum + solenoid + vacuum controller with plastic rod and switching drum (23) inserted into manifold. This all should enhance torque above 5000rpms or so.



Intake flaps are fully operated by electric motor (no vacuum) attached to the lower intake manifold (or fuel distributor as it is called in manual). I presume position sensor is part of motor body.


Connector is on the body of motor all buried down below intake manifold.



However i tested the flaps via VCDS output test and i could hear motor buzzing as it engaged the flaps.
When i logged open angle of flaps they seemed to be actuated from cold start. I can post proper graph with temp & angle & pedal position.

[maro]

As for performance issue, right now 98 octane seems to influence car's behavior to the point i am satisfied with it. I want to drive it more in order to confirm long term behavior.

Could you please elaborate more about solving NOX sensor issues?

I can imagine a few approaches
- modifying ECU's flash to mask DTC set by sensor (heater, signal range, NOX catalyst efficiency, ...). Would not there still be issue on emission test?
- modifying ECU's flash to "code out" NOX subsystem. Homogeneous mode would be primary mode then and all benefits of stratification would be gone but no check engine light no failed emission test.
- tapping into MED ECU and NOX ECU with some arduino simulating CAN communication so MED ECU would be fooled and turned on stratified mode
- buying some emulator like NOXem for BMWs, which is basically Bosch wideband O2 sensor with its own ECU, NoX concentrations are "computed", NoX cats are useless and can be removed, i could not find any emulators for Skodas )-:
- ?

[drbluetongue]

As for performance issue, right now 98 octane seems to influence car's behavior to the point i am satisfied with it. I want to drive it more in order to confirm long term behavior.

Could you please elaborate more about solving NOX sensor issues?

I can imagine a few approaches
- modifying ECU's flash to mask DTC set by sensor (heater, signal range, NOX catalyst efficiency, ...). Would not there still be issue on emission test?
- modifying ECU's flash to "code out" NOX subsystem. Homogeneous mode would be primary mode then and all benefits of stratification would be gone but no check engine light no failed emission test.
- tapping into MED ECU and NOX ECU with some arduino simulating CAN communication so MED ECU would be fooled and turned on stratified mode
- buying some emulator like NOXem for BMWs, which is basically Bosch wideband O2 sensor with its own ECU, NoX concentrations are "computed", NoX cats are useless and can be removed, i could not find any emulators for Skodas )-:
- ?

Do you get stratified mode when you cruise along at part throttle, if you log your AFRs? Or just at idle?

[maro]

Do you get stratified mode when you cruise along at part throttle, if you log your AFRs? Or just at idle?

No at all. OEM NoX sensor was busted the time i bought the car. It sometimes reported plausible signal so engine rarely switched on stratified but sensor was already giving his goodbyes.

I gave chance to sensors from China (DIY, cut cables, solder, heatshrink) but it turned out to be a mistake. One sensor came with broken heater another one was giving totally wrong data etc.

You can look at pictures here (posts from Maro )
https://bit.ly/3fmoXDB



Right now i have this chinese sensor screwed in exhaust, 2 CANbus cables cutted and rerouted under passenger's footwell. 2 cables from NOX ECU 2 cables to MED ECU at your fingertips. MITM with Arduino is much easier this way. Power cables are left untouched in order to pass NoX sensor heater checks.
I'm able to generate canbus frames and see corresponding NoX sensor voltages (O2 part) and NoX concentrations.
I always end up with

17441 - Sensor for NOx (G295)
P1033 - 002 - Signal too Low

So i guess i send signal with incorrect range (lower, upper threshold) or signal needs to reflect real drive conditions (plausibility check is not passing).

I am not keen on solving this with "emulator" approach. Reflashing ECU with "cured" firmware is much better then hiding arduino behind passenger's compartment
At worst, sacrificing stratified mode is also acceptable. For 2.0 engine with 4x4 8 liters / 100 km (29,4 US mpg) is not bad at all.

[drbluetongue]

An update - I've been working with Maro offline as I have had some trouble posting replies on this forum.

I have managed to get stratified mode working at low load driving without NOx sensor, cats or EGR.

Seems to work okay, the odd misfire but will report fuel economy difference after this tank is empty.

[Pretzell98]

Gday, have the exact same model mk5, ran around in circles for ages chasing this issue and in my case jade zero faults on vcds. Ended up cleaning the dreaded intake valves and the issue disappeared completely.

[saabman]

This is very neat.

Is the Arduino code available?

[drbluetongue]

Update:

Maro and I have been doing a ton of work on this the last 6 months - he has now disabled his NOx system completely as I did through editing the ECU ROM. I have reverted to homogenous only as I was having too many misfires (probably my intake valves are a mess).

There's a few fields you need to do to turn off NOx and have the car run stratified.

1. set CWSKR to 0 (This kills NOx diagnostics from stopping stratified mode)
2. set most of the middle bits off on CWNLKO (check FR compared to your bin)


Also - to turn off that rough as hell cold start catalyst heating you can set TKHMX to 0.

For anyone reading this with 1.6FSI I have made a pretty massive definitions file here:

Golf 5 1.6 FSI - basic map for 03C997056M

[saabman]

That is great work - now I need to learn how to read and write the map - any pointers on where I can find out how todo it /what I need?

[drbluetongue]

Yes, I currently use a Kess v2 clone from AliExpress. It works awesome, does the checksums for you and writes changes in about 15 minutes - Maro had issues with the 2.0 FSI with MPPS v16 (a cheaper option) so recommend Kess v2 for sure.

[saabman]

Sweet thanks for that - looks like I'm off to spend more money

[saabman]

Well its been a long time since I updated this saga of the BLX engine

As it turned out not long after I was last here sydney had a deluge of rain and while my daughter didnt get flooded out - she did make a trip to the shops which involved driving through a bit of water over the road. The Golf sucked in a mouthful of water and stopped. That wasnt so bad until the NRMA monkey turned up and pulled the plugs and turned the car over for a bit then re fitted the plugs and proceeded to start the car. At which point it sucked more water out of the manifold straight into the engine and it went bang. That was the end of that.

DONT LET THE NRMA EVER TOUCH YOUR CAR.

So I have had the Golf sitting in my backyard for long enough so it is now time to move it on Just waiting for the wreckers to give me a price for it..

[JustCruisn]

Can I grab a part off it ?