Hi 

I have a 1.6 Octavia diesel greenline 2010 , the problem i have is that every so often the car starts to be really hesitant won't accelerate jumping about like a kangaroo

with blue smoke out of the exhaust, it does not come up with any faults like engine management lights etc and iv'e scanned it and no faults logged.

If i blip the accelerator some times it clears and then it's ok or if i switch the engine off and re start it's ok, then it can go for miles before it does it again.

Any ideas i'm hoping it will just go away, (knowing me not much chance of that lol) all the filters have been changed in the last three months inc engine oil etc, it started 

doing it about four days ago. It's  CAYC engine. Thank you. Steve.

 

  

I'll take a guess and say fuel supply issue, partially obstructed injector perhaps.

 

Perhaps a fuel additive, fuel filter change and Italian tune up will clear it.

 

Hopefully it's not a fuel pump issue.

 

Just my thoughts, see a pro if required.

 

Any more thoughts as to the problem i have?, the car finally came up with a fault code P0101  maf circuit i changed the maf but the fault is still there.

How it starts is like this if i am doing about 30 mph in 4th gear put the car into 5th gear put my foot down and then the car starts juddering and won't pull

with smoke out if the exhaust if i change gear to 2nd let the engine revs go high it suddenly shoots forward and is ok, if i keep the engine revs high it does not do it

and please don't say just keep the revs high its the same if i'm in 3rd gear with low engine revs and change to 4th put foot down and starts juddering again and same as before drop a gear or two get high engine revs and it shoots forward and is ok again, but it does not do that all the time. some times it's ok.

Thanks. 

Maybe you have a turbo issue or the actuation of, when engine rpm is high and vacuum is increased there is enough force to put the turbo mechanism into the high boost position but not when engine rpm/vacuum is lower therefore when you accelerate at low rpm the turbo isn't supplying enough boost and the engine will struggle and partially unburned diesel may be the cause of the smoke.  Perhaps a vacuum leak somewhere or partially sticking VNT mechanism.

 

It could just be as simple as a bad electrical connection causing intermittent running, stranger things have happened due to mice nibbling at wires and corrosion setting in.

 

You've checked the air filter is not overly clogged despite being replaced recently?

Turbo Actuator sticking maybe or a problem with the N95 vacuum valve??

Thank you for your suggestions, this morning took off the MAP sensor off to clean it it was oily but not dirty cleaned it went for a run and it's still the same, checked the wiring the car has only done 50.000 miles. So re turbo actuator sticking and the N95 valve what do i do to un stick it and where is the valve?. i have done a search but came up with nothing. The only other thing is if anyone with VCDS in the Doncaster area can do a scan for me as i only have Carista. It came up with a fault with the glow plug light flashing but when i scanned it it showed nothing. it's really frustrating things were a lot simpler 40 years ago when i was a motor mechanic ruddy modern cars lol. Thanks.

Sorry forgot to mention if i drive the car with the MAF disconnected it drives ok.

Did you replace the MAF  with a cheap ebay item?  I've read they are problematic so when disconnected the ECU uses a default setting rather than an incorrect reading from the MAF.

 

As you know already it will drive ok but not optimally for engine and atmospheric conditions.

 

There are videos on YouTube that show testing the MAF with a multimeter.

maf.

 

buy a genuine one and youll be alright 

 

pattern version sensors just dont work well in vag engines. CTS is the same. 

Thanks for the replies i did replace the MAF with a genuine one albeit from a breakers yard it was very clean, i have a friend that owns a car spares shop he got me a Hella MAF and that defiantly did not work the car was un drive-able.

yeah,but if it was from an engine sitting in a breakers its already possibly life expired or was dying slower than whatever killed off the donor car. 

Ok well i hold my hands up, it was all my fault, it was the air filter i had a k&n filter in the car and last year decided to clean it i bought the proper k&n cleaning kit with the oil dispenser. I must have put too much oil on it (but didn't think i had) but that was six months ago with too much oil on it it got clogged and the MAF did not like it, i changed it for a Bosch paper filter and the car is fine now done a 150 mile round trip today and not a problem. Needless to say i won't be going back to the k&n.

Hello it's me again hope you are all well.

 

So i thought it was my fault turns out it wasn't  (phew) i have still got the fault still the same, i bought a brand spanking new genuine VAG MAF cost me £150 😪 only to fit it and boom there it goes the same , anyway iv'e ordered a new N75 not N95 valve today going to fit that and try that , i had the car scanned with someone who had VCDS oh and by the way i checked the inter cooler pipes to the best of my ability and did not find any splits. Here is the scan can anybody decipher it and knows what's going on. Thank you Steve.

 

Address 01: Engine (J623-CAYC)       Labels:. 03L-906-023-CAY.clb
   Part No SW: 03L 906 023 AG    HW: 03L 906 023 AG
   Component: 1,6l R4 CR td H23 5697  
   Revision: --------    Serial number:               
   Coding: 00114016032500080000
   Shop #: WSC 73430 031 00999
   ASAM Dataset: EV_ECM16TDI02103L906023AG 001003
   ROD: EV_ECM16TDI02103L906023A_001.rod
   VCID: 6BDF9A6E8285F9DECE-803E

1 Fault Found:
7329 - Mass Air Flow Sensor (G70) 
          P0101 00 [096] - Implausible Signal
          Intermittent - Not Confirmed - Tested Since Memory Clear
             Freeze Frame:
                    Fault Status: 00000001
                    Fault Priority: 2
                    Fault Frequency: 1
                    Mileage: 81057 km
                    Date: 2020.06.29
                    Time: 09:41:12

                    Engine speed: 1367.00 /min
                    Normed load value: 0.0 %
                    Vehicle speed: 69 km/h
                    Coolant temperature: 76 °C
                    Intake air temperature: 19 °C
                    Ambient air pressure: 1000 mbar
                    Voltage terminal 30: 14.231 V
                    Unlearning counter according OBD: 38
                    Environmental conditions-AMP_ENVD: 996.078 hPa
                    Environmental conditions-Battery voltage: 14.2 V
                    Environmental conditions-FRF_RC: 255
                    Environmental conditions-MAP_MES_ENVD: 1022.87 hPa
                    Environmental conditions-MAF_KGH_MES_ENVD: 32.1252 mg/stroke
                    Environmental conditions-FAC_MAF_CYL_KGH_RATIO_FIL_ENVD: 1.99
                    Environmental conditions-ANG_SP_BPA_ENVD: 79.6 %
                    Environmental conditions-ANG_SP_EGRV_ENVD: 0.0 %
                    Environmental conditions-ANG_SP_PORT_ENVD: 14.9 %
                    Environmental conditions-ANG_SP_THR_ENVD: 95.7 %
                    Environmental conditions-SF_ENG_STATE: IS
                    Environmental conditions-Ambient temperature: 13.50 °C

Readiness: 1000 0000

IF it really is MAF related and you've fitted a new VAG part (new parts can be faulty) I'd suggest checking the wiring from the MAF plug up, maybe using a DMM with continuity beep whilst jiggling the wire.

Do you know where the three wires go?, iv'e checked the voltage that was 4.96 volts and what are the three wires i presume that 1 is power 1 is earth and 1 is signal to the ecu which is which, i have tried to find a circuit diagram but not had any luck. There is loads of info about 5 pin MAFs but i have not found any re 3 pin MAFs.

Cheers.   

I have to say that:

 

7 hours ago, adokS12 said:

Implausible Signal

 

sounds like an open circuit. Not guaranteed, but it is the most likely thing.

3 pin MAF?

Hi Hope everyone is well, just an update to let you know what was wrong, after fitting a new N75 valve it still did not work, so i did a boost pressure test that was ok then i had the car de-carbonised and that did not work. so out of sheer desperation i got the new MAF changed for another new original MAF and that was it!. As MicMac suggested the NEW one was faulty all that for a faulty new part never mind it's sorted now. Thank you to everyone for your help and stay safe.

Steve.    

Glad you got it sorted.

Ok well here i am again, hope everyone is well. It seems the car had another fault one i could not figure out. Here's the story, after all the messing about with the car it was doing my ed in, so i took it to a VAG specialist in Sheffield for a diagnosis check. I had the EGR deleted and the DPF done 5 years ago, so after the garage had done the diagnosis they found that exhaust gasses was entering the inlet, apparently the valve on the EGR can come open if not physically blanked off, so the solution was to blank it off they did it not from the EGR but the throttle body where the pipe from the EGR goes to the throttle body.

So anyone who has had there EGR deleted make sure it is physically blanked off it may save you a lot of heart ache.