2007 A3 BMN PD170 Wont Stay Started

[Adammann93]

Hello Everyone,

Looking for any ideas on what my issue may be.

last week when joining the motorway when i put my foot down the revs started "surging" (revving up and down when foot on pedal) while loosing power and blowing some white smoke out the back. Pulled on to the hard shoulder managed to get it started but it doesn't stay started for long and was unable to drive it away so got recovered.

The day after i plugged my laptop in to read any codes and got the following (Ignore the MAF that was me unplugging it)

Address 01: Engine Labels: 03G-906-018-BMN.clb
Part No SW: 03G 906 018 DN HW: 03G 906 018 DN
Component: R4 2.0l PPD1.2 G 1247
Revision: --H42--- Serial number: AUX7Z0G4FN3060
Coding: 0000172
Shop #: WSC 06314 000 00000
VCID: 74E769D717BB262607-8020
2 Faults Found:
000665 - Boost Pressure Regulation
P0299 - 006 - Control Range Not Reached - Intermittent
Freeze Frame:
Fault Status: 00000001
Fault Priority: 5
Fault Frequency: 1
Reset counter: 40
Mileage: 217022 km
Time Indication: 0
Date: 2021.02.16
Time: 16:28:53
Freeze Frame:
RPM: 2272 /min
Torque: 160.0 Nm
Speed: 34.0 km/h
96.33 %
Voltage: 14.46 V
Pressure: 2492.1 mbar
Pressure: 1065.0 mbar
000258 - Mass Air Flow Sensor (G70)
P0102 - 007 - Signal too Low - Intermittent
Freeze Frame:
Fault Status: 00000010
Fault Priority: 5
Fault Frequency: 2
Reset counter: 40
Mileage: 217023 km
Time Indication: 0
Date: 2021.02.16
Time: 17:28:04
Freeze Frame:
RPM: 0 /min
Torque: 0.0 Nm
Speed: 0.0 km/h
0.00 %
Voltage: 12.09 V
Mass Air / Rev.: 872.0 mg/str
Mass Air / Rev.: 0.0 mg/str
Readiness: N/A

The garage has inspected my turbo and said its fine and that more investigation needs to be done to find the issue, they cant get onto it yet due to being too busy.

I'm hoping that someone on here has some experience with the issue.

My thoughts... Lift pump in the tank failed? it does start with difficulty but is rough and doesn't stay started for long, almost like it isn't getting the fuel it needs. Doesn't throw any codes though and I cant get back to the car at the moment to do any VCDS logs. I say lift pump as it had a new tandem pump a few months ago for suspected seal failure.

Other thing could be injector seals ?

Any help with this would be much apricated, it would be good to have a few ideas before I go back to the garage.

 

[wha3]

It could potentially be the injector(s) deciding to die.
The issue that I had with mine was the variable cam timings been out of whack, this meant that the engine ran like ***** and spat lots of white smoke out the back of it, but I doubt that it would suddenly happen to your car.
The cam timings can be checked with VCDS under engine < advanced measuring blocks
From memory, you're looking for torsion value and fuel flow (I think)
Torsion should be as close to 0.00 as possible, but should drop a little when you hit the accelerator, if it doesn't then you know its gone to far
For fuel flow, at idle I have mine about 0.6 l/h and it seems to run happily on that.

 

[aqibi2000]

Fuel filter ever been changed?

You could always unplug the fuel feed going to the engine and put it into a bucket to confirm the flow of the lift pump, just turn the key to ignition and it should run for 10 seconds or use VCDS to prime.

do not throw money at parts guessing

 

[Adammann93]

Yeah fuel filter had been changed recently, garage have managed to have a proper look at it this time and said its the turbo so its waiting a new one.
Don't know how they didn't get to that conclusion 3 weeks ago when they had an initial look!

They have lent me another a3 in the meantime so I'm no longer carless at least.