Intermittent Power Golf 2015 MK7 R

[huphuphuppi]

Hey Everyone,

I bought 2nd hand Golf MK7 R back in May, ever since I've been trying to figure out what is wrong with it - most of the time it feels low on power when compared to my daily MK7 2.0 TDI.

Then sometimes it REALLY wants to go (I would call this normal).

What I'm noticing:

• Power is normal directly after starting (warm or cold)
• Reduced exhaust noise when low on power
• I have an upgraded intake and elbow - can clearly hear the air getting sucked in when normal, it's quieter when low on power
• Shifting isn't "precise" when low on power and accelerating. Shifting is precise and works like a dream when normal power
• Goes into this "low power mode" after driving straight ahead for a random period
• Power comes back when harder braking and cornering, or sometimes when I accelerated from a standstill in to a corner
• Randomly the car is normal as well, noticed it sticks around longer when it is cold outside (below ~17C or 60F)
• Happens in all modes (comfort, normal and sport)

Done so far:

• Re-installed the factory intake (no difference)
• OEM PCV replaced
• OEM Waterpump and housing replaced
• GFB DV+ diverter and new OEM diverter valve
• Cleaned intake valves
• Replaced Spark plugs
• Checked the turbo actuator adjustment (3.74V)
• New Haldex pump
• new N80 valve
• Checked DSG oil level and ran all adaptions (no errors)
• Ran turbo and throttle body alignment
• NO ECU or TCU errors
• I don't believe it had a tune (ECU and TCU flashed in 2015, year of manufacture)
  • I want to get a tune, but not until I've resolved this issue!?

I have a VCDS cable and software, would appreciate if anyone has an idea where I should look to now? This is keeping me up at night
- Any actuators or sensors I should replace
- Possible faulty part to look at
- What I should log during a drive that might pinpoint the issue?

Thank you in advance - Tim

 

[Diggs24]

You should get a dongle+Simostools and log the car to see what it's actually doing. VCDS is too slow.

https://www.golfmk7.com/forums/index.php?threads/open-source-tuning-solution.380998/

https://www.sparkfun.com/products/17493

 

[huphuphuppi]

You should get a dongle+Simostools and log the car to see what it's actually doing. VCDS is too slow.

https://www.golfmk7.com/forums/index.php?threads/open-source-tuning-solution.380998/

https://www.sparkfun.com/products/17493

Thanks Diggs, I've found a seller in Australia for the Dongle & I'll have a look through the 20 or so pages after work to see what else I need.

 

[Diggs24]

Thanks Diggs, I've found a seller in Australia for the Dongle & I'll have a look through the 20 or so pages after work to see what else I need.

Android device with 9.0 or higher as your interface
SimosTools app off the google play store (for logging)

 

[swifty1]

Sounds like it could be a case of heat soak and varying fuel quality to me

 

[huphuphuppi]

Sounds like it could be a case of heat soak and varying fuel quality to me

Hi Swifty,
I'm always using Shell 98. I did log the intake temperature once and it was about the same power or no power :-(
Your comment is leading me close to my next suspicions though (low pressure fuel pump or something going wonky on the intake end)
I've ordered the dongle diggs suggested (2 weeks eta) - hopefully better logs than VCDS.
Thanks for your suggestion.

 

[huphuphuppi]

Hi Diggs,
I've just received the dongle, but I think it migh be DOA - it flashes red once shortly on power (usb or car). I can connect WIFI and use SavvyCan. Send it back or reflash it? What do you think?

 

[Diggs24]

Are you using simostools and android? It would connect over BLE not WIFI.

 

[huphuphuppi]

Are you using simostools and android? It would connect over BLE not WIFI.

Yes I wanted to, but I can’t find the dongles Bluetooth ID when trying to add it. I’m not getting the red or green leds to light up.

 

[Diggs24]

First install driver on PC:

https://www.silabs.com/developers/usb-to-uart-bridge-vcp-drivers

Download this firmware and unzip the contents somewhere on the PC:

https://github.com/Switchleg1/esp32-isotp-ble-bridge/releases

Hook dongle to PC using USB, it should have a hole in it you can push down with a paperclip, push it down then run install.bat while holding it down. it should go .........for a bit then the window will close. That's it.

Plugging it into the car and turning to accessory position it should light up red then green when it connects. Simostools will find it automatically. It has a name in Simostools, don't change it or it won't connect.

 

[Diggs24]

bluetooth and location permissions must be enabled on the android device.
if it sees it but wont connect try changing bluetooth permissions from always to ask.

 

[huphuphuppi]

Hi Diggs, thanks for your help. It did "work" the LEDs are not flashin the right colour, but I've connected and did my first run.
Datazap Logs
I'm still learning the app, next one will try the the automatic logging (using cruise control button) and log the DSG as well. I need more time in the day. Great app btw!!!

 

[Diggs24]

3rdgear
2000 rpm
floor it
wind out the gear

need better data

 

[huphuphuppi]

Hi Diggs,
Thank you for helping!! I owe you a beer (?). I've finally managed to pull all strings together and do a 3rd gear pull: 3rd Gear Pull
I've had a look and had a few things stand out (not that I'm the professioinal though):
- tps % isn't staying open?
- Knock on 1 and 4 (not much -2.25), reducing as rpms increase
- fp mpi is higher than fp mpi sp
- exhaust cam, would this be normal? I'm thinking it changes it to get the turbo to spool up?
- ambient pressure sensor seems to be fluctuating (this could be a big impactor ???)

 

[Diggs24]

-normal
-normal
-normal
-normal
-normal

Everything looks fine other than IATs are high. When it's hot out it will pull timing. I suspect it's just getting heatsoaked sometimes and that is what you are feeling. The stock IC is just rubbish. It's one of the best upgrades after a tune for this paltfrom.