Audi A2 1.2 tdi turbo doesn't work properly

[Nikola_is]

Hello Everybody,

 

My Audi A2 1.2 tdi.

Everything you need to know about it.

The turbo is refurbish one of our company specializing about this service. On 1 week life.

The VNT is working well and it is not blocked.

N75 and N18 work well.

Mass air flow sensor and intake manifold pressure / temperature sensor as well.

No any visible any leakage from hoses, manifolds and intercoolers.

EGR, air filter and fuel filter is new ones.

No any alarm on VCDS.

Running performance are 130 Tkm.

The fuel consumption is 5l / 100km. 

When I drive the car, the car is in the middle of the road. Only about 2400U / min are then about 2bar of load pressure. In my acquaintance, if he gives at about 1500 rpm full throttle intake manifold pressure and charge pressure about 1 second delayed immediately high.

I am grateful for every suggestion.

Greetings from Bulgaria!

LOG-01-011-AudiA2_12tdi_BS_turbo_23042017.CSV

LOG-Audi A2_10052017.CSV

[Phoenix A2]

May you log the boost pressure (Group 011) in the following way: Tiptronic 3rd Gear starting from low rev (1200-1400 U/min) accelerate with full throttle (kick-down) up to about 2500-3000U/min?

That helps for comparison.

 

[Nikola_is]

Thank you for your advice, I will make it ASAP.

[Nikola_is]

Hello,

 

Here is the data.

As you will see acceleration is slowly and turbo delay is big.

 

3rd_kickdown.bmp

LOG-AudiA2_12tdi_3rd_kickdown_13052017.csv

[Nikola_is]

If this test was done with cold engine the result will be worse then with warm engine.

Bearbeitet 13. Mai 2017 von Nikola_is

[Phoenix A2]

For me your log of charge pressure looks OK.

The turbo delay of ANY-engine (time until current charge pressure reaches target charge pressure) is usually more than 1 second when accelerating from revs below 2000 U/min.

Your air pressure in idle is bit low compared to sea level, i assume you did the test on a small hill? That does have a little effect (additional offset of 100mbar) on the turbo delay, too.

 

Are you experiencing any other symptoms beside the (measured) turbo delay?

 

 

PS: Welcome to the forum (first post)!

 

[Nikola_is]

I compare with my Skoda Roomster 1.9tdi where I can't see such of turbo lag.

The diference is comming in trubo working on the same area and altitude.

And that my car when I make the test in Basic setting (011) Charge pressure control - the deviation between "active"and "inactive" must be at least 100.0 mbar and my  on car when the coolant temperature is 90degr.  the deviation is maximum 70mbar. When the car is cold the deviation is 40mbar.

When I make the same test on my Skoda whith cold and warm engine that deviation is near 120mbar.

Another issue is fuel consumption which for this car is not normal.

I never past more of 700 km witn one full tank 30l.

 

LOG-01-011-AudiA2_12tdi_BS_turbo_40degr_23042017.CSV

LOG-AudiA2_12tdi_BS_turbo_90degr_10052017.CSV

[Nikola_is]

Can you make the same tests on you car and I will compare the result?

If it possible check and Basic setting (011) Charge pressure control as well.

Thank you in advance.

[Phoenix A2]

vor 15 Minuten schrieb Nikola_is:

Can you make the same tests on you car and I will compare the result?

If it possible check and Basic setting (011) Charge pressure control as well.

Thank you in advance.

 

No problem, i will do the same tests for comparison and post the results (next monday at latest).

 

[Nikola_is]

Thank you.

I would like to show you some question form another forum may it is good point for the next step.

- Is the cooling liquid clear and clean. Do you need to fill it up. --------It was changed with new one before last week
- is the oil rising? Do you smell diesel in it? ---I think is rising.It not possible to check the oil level because that stick is oiled to the small ball. Regarding the smell I'm not sure.
- what's the pressure at the oilstick pipe when running? is it blowing, or sucking? -------Blowing
- what's the mileage? ----- 135000km but I'm not sure because I'm not the first owner.
Regarding the smoke ...no any sign of such a problem. The smell of the exhaus gases there are look clean.

[Phoenix A2]

Here are the results of the measurements i did today. Hope it can serve as comparison example.

Coolant temperature was at 90 degree.

Common: No fault codes from ECU, fuel consumption as low as specified (3l/100km or less) possible .

 

1.Basic setting for measurement group 011

 

The difference between 0% and 100% duty cycle of N75 is about 70-80mbar.

 

2.Measurement run: In tip tronic mode, third gear starting from ~1200 rev/min, then full acceleration (kick-down) up to 3000 rev/min.

 

From the experience of  my ANY, in this situation the current charge pressure equals the target charge pressure when ~2000 rev/min are exceeded.

 

ANY_MWB11_BasicSetting.CSV

ANY_MWB11_MeasurementRun.CSV

 

 

[Nikola_is]

Thank you for your efforts and time made this test for me.

I'm really appreciated it.

Please see the file with the comparison what I do with my and your data.

You will see that my Audi is going slowly compare with yours and difference is 30% (5sec).

And bigger fuel consumption.

That's mean I have a problem.

I think that I have fuel into the oil.

I will know exactly after few days.

Do you have experiance with such of problem?

What I have to check at first.

 

LOG-AudiA2_12tdi_3rd_kickdown_13052017.xlsx

[Nikola_is]

Please take a look on comparison of EGR between both cars in the same condition.

Do you have idea about this difference?

Why you specified Exhaust Gas recirculation is always 1000?

Are you sure that your EGR is working?

I forgot tha mension the I live is 1000m above the sea level.

EGR comparison.xlsx

[Phoenix A2]

Sorry, that was my fault by accident, wasn't the stock configuration for that test (thought it was).

For an better comparison, i made another measurement run, now completely stock.

 

2. Measurement run: In tip-tronic mode, third gear starting from ~1200 rev/min, then full acceleration (kick-down) up to 3000 rev/min.

 

The effect of blanked EGR-Valve is minimal as it is closed during full engine load anyway.

What i don't know: how big is the effect of lower air pressure at 1000m above sea level. To be sure that is does not make a big difference, you can maybe repeat the test at around sea level altitude.

 

To summarize your symptoms:

-increased fuel consumption

-charge pressure rises slower than usual, that should also mean lower engine-power (or increased rolling/driving resistance)

-fuel deposition into oil

 

Concerning charge pressure i would check the following:

-all pressurised air pipes are airtight, including intercooler?

-compressor wheel of the turbo does not have too much play?

-compressor wheel  is entirely intact without noticeable wear at the blades?

-you stated that the turbo is a refurbished one, sometimes the mechanical adjustment the bolt that connects the vacuum actuator with lever for VNT actuator is not correct, but from your results of the basic setting i don't think of a problem there.

 

ANY_MWB11_MeasurementRun.CSV

[Nikola_is]

Thank you for your new data.

Now I see that you EGR works properly.

Regarding the time you reach 3000rpm for 10sec. Which is, I think the correct result.

 

Here is my replies of your questions

To summarize your symptoms:

-increased fuel consumption ------ Yes 5l/100km

-charge pressure rises slower than usual, which should mean lower engine power (or increased rolling / driving resistance) ---Yes, it is, just we have to find what is the reaso for this

-fuel deposition into oil  ---- This morning I check the oit level when I leave the car all night without oil stick inserted, just to be sure that I have accurate measurement. The oil level is near 8mm up then acceptable high level.

 

Concerning charge pressure i would check the following:

-all pressurized air pipes are airtight, including intercooler? - We check the several time and intercooler is well. No any sign or sound which shows leakige problem.

-compressor wheel of the turbo does not have too much play? ---- The si comming from MOTO SYSTEM Germany which is specialized for such of service. Before to instal it which check everything what you ask me.

-compressor wheel is entirely intact without noticeable wear at the blades? ----- No noticeable wear 

-youstatist that the turbo is a refurbished one, which is the mechanical adjustment of the bolt. ----we not adjust the bolt because We expet this to be done from the supplier and from our side looks to be OK.

 

To be honest this is the second turbo from MOTO SYSTEM because with the first one considering the problems what I have I return the turbo and ask for another one. Because  I think that the problem comes for turbo charger. 

And the turbo have and 1 year warranty so, I couldn't expect that thay will try sell me turbo which is not works properly.

I think that the problem comming from lower engine power and lack with exhaust gas which is not enough quantity to turn turbo wheel. But what is the reason of this and what is connection with high oil level.

About increased rolling / driving resistance, do you have idea how to check this?

 

[Nikola_is]

I spoke with specialist about oil measurement.

He told me that the way as I measured it not the right one.

I have to start the negine for 30sec-1min and after I can check the oil level.

In this way the oil level is correct so I can say that we can stop to thinking about this problem with fuel into the oil.

Lets focus over the slower rises of turbo charger and bigger fuel consumption.

 

[Phoenix A2]

vor 16 Stunden schrieb Nikola_is:

Lets focus over the slower rises of turbo charger and bigger fuel consumption.

 

I am figuring out a way to measure the rolling/driving resistance (including drag coefficient) and come back with the result.

 

[Nikola_is]

I hope that I will can repeat later to make the comparison.

But what have to check on the car concern this problem.

May be I have to pass a wheel align test.

 

[Romulus]

Am 18-5-2017 um 23:57 schrieb Phoenix A2:

 

I am figuring out a way to measure the rolling/driving resistance (including drag coefficient) and come back with the result.

 

Apart from the option of measuring using OBD (IIRC the app Torque has an option for this) you could use gliding phases (like in Pulse & Glide) from a certain speed to another (say, 120 km/h to 80 km/h) at least for comparison between vehicles.

 

Procedure simplified: bring the vehicle to a constant speed of e.g. 120 km/h. At t=0, engage Neutral gear and start time measurement (stopwatch). Stop the time as soon as the lower threshold speed (e.g. 80 km/h) is crossed. Compare these gliding times between vehicles for qualitative comparison.

 

Using the formulas for drag you could try to come to quantitative comparison. It should not be so difficult, since I did this myself together with my father as a school physics experiment when I was 17. But I should dig it out again, it's more than half a man's life ago

[Phoenix A2]

That's exactly what i am figuring out: can gliding from a constant speed until the vehicle stops be used to calculate driving resistance accurate enough (comparable)?

What will make it difficult though, is to find a suitable road section without incline for about ~2km. And there should be at best no wind.

 

[Romulus]

Hm, yes, you're right... 

I can confirm that the EV record trajectory highway we used in March is suitable (to my 17-year old standards) - there I did my runs back in 1995...

 

Both incline and wind could be compensated by repeating the tests in the opposite direction. 

[Phoenix A2]

Compensation by repeating the test in opposite direction is a good idea.

 

[Nikola_is]

Hello again,

 

Thank you for the ideas how to check the rolling/driving resistance.

The test with 120km/h to 80 km/h I uderstood how to make it.

But for the test with gliding from a constant speed until the vehicle stops, from which speed I shoud start.

I live in the mountain around 1000m above see level. And around me I can't find  straight road 2km long.

The maximum what Iknow is 500m long with not so good asphalt road cover.

But if I can went to the field area but this is will not happen soon.

Please  give me your data and in what condition was taken and will try to find the way to repeat the test.  

 

[Nikola_is]

What about the tyres.

What are your tyres?

I tthink for this test they will be important as well.

[Romulus]

The main variable is tire pressure. Make sure you set and record that properly.

[Nikola_is]

Dear Frends,

 

I still haven't chance to check the car rolling/driving resistance.

But I found the right road for this test.

Unfotuntely it is  about 2 hour driving from me.

Can you tell me again from which speed I have to start and to stop 0km/h?

Thank you. 

[Phoenix A2]

Am 9.8.2017 um 20:35 schrieb Nikola_is:

I still haven't chance to check the car rolling/driving resistance.

But I found the right road for this test.

Unfotuntely it is  about 2 hour driving from me.

I made a testrun on a road i believed were absoltely flat, but the testrun in reverse direction showed that it was not really flat (wind speed was almost 0).

Therefore i recommend to do the testrun in reverse direction too as double check.

 

Zitat

Can you tell me again from which speed I have to start and to stop 0km/h?

As basic rule: The higher the speed the better rolling resistance and drag resistance can be distinguished. Higher speed needs longer straight, flat road though (or splitting testruns, e.g. between 110->50km/h and 50->0km/h).

I think a speed around 110-120 km/h makes a good start. For measuring the current speed vs. time i used diagnostic data from the car (via VCDS). This is more accurate than a GPS receiver.

 

For post-processing of the collected data here is a link to a page which offers instructions and a sample-excel sheet to do the calucatations: Rolling Testrun

[Nikola_is]

Thank you very much for instruction and for the file as well.

Can you tell me which group is the best to use for the speed measurement with VCDS?

May I use the time frame from the VCDS as I will save a log file durring the test?

And another question.

When I examined the file , inside i saw 18 measurements with different start speed.

I have to do it in the same way or only one meassurement 120-0km/h is enough.

Enclosed I sent you the English version of this file.

Probably it will be helpfull for someone else who doesn't speak German.   

 

rolltest_EN.xls

[Phoenix A2]

Am 11.8.2017 um 09:06 schrieb Nikola_is:

Can you tell me which group is the best to use for the speed measurement with VCDS?

May I use the time frame from the VCDS as I will save a log file durring the test?

You can use group 6 (value 1) from ECU. Timestamps are added from VCDS, that's right.

 

Zitat

And another question.

When I examined the file , inside i saw 18 measurements with different start speed.

I have to do it in the same way or only one meassurement 120-0km/h is enough.

Imho only one measurement 120-0km/h is enough to gather the time spans for the different start speeds.

Doing several measurements 120-0km/h and calculating averages for the time spans makes them more accurate though.

 

[Nikola_is]

Finally I made my rolling test.

I can't say that was in the best weather condition.

It was a little bit strong side wind.

But I made in the both direction and calculate average result.

Please take a look over the file let me know what is the result and what is your opinion.  

Thank you.

rolltest_EN_Audi_A2_1.2tdi_BG.xls

[Phoenix A2]

With the measurements you made, the excel sheet calculates a cw*A of more than 1.0 (done Iterations until correction values reach 0.0), which is far more than the 0.545 from theory (cw: 0,25 / A: 2,18).

I think the wind may had an influence on the measurement which could not be compensated with averaging result of opposite direction.

In the meantime i attempted to do such measurement with my 1.2 but did not succeed to determine a plausible result either.

It seems that it is not as easy as on first thought.

 

Relating to thread title: Original intention was to find hidden driving resistance as cause for slow (turbo-)acceleration.

What i have experienced as another possible cause for increased fuel consumption is a slight mis-sychronisation of the cambelt.

It can be readout via VCDS (ECU => Measurement => Block 4 Value 4).

See also this thread.

[Nikola_is]

I will try to make  this test again when the weather condition is better.

What I remember on VCDS (ECU => Measurement => Block 4 Value 4) shows 0.0.

But I will check again.

 

[Nikola_is]

I noticed that around the EGR valve. I have oil remains and in some area have marks like oil spraying.

Please take a look on the pictures.

Do you think that my engine  loose the boost pressure because of some gaps into the EGR valve or the reason is something else.

Please be informed that I still driving the car with 4,8l average fuel consumption.

 

[ssk]

hello. what was your car problem ? i have the same issue here... 

 

[TitusM]

Not sure if this topic has a conclusion or not. 

For me the bad consumption had several sources:

1)The T on the fuel filter (if you have the metal version -- the older ones) -It was cracked and air got into fuel system.

2)Air intake leaks -- on the oil stick pipe one o-ring was missing - after plugging this there was a big improvement. Also check the oil level sensor for missing or worn out orings.

3)air leak near turbo intake hose -- the o-ring was warn out and turbo was aspirating false air. 

4)tandem pump might be defective inside - this is yet to be proven after I replace the current one with a new one. Find updates on my post.  Usually the older version of tandem pumps had that issue with the hose plug getting loose BUT also with the seals between oil side and fuel side and vacuum side. 

 

You need to get a smoke machine for detecting leaks. You would not believe where the leaks are until you test for it. The car runs well with this leaks also and you cannot find anything specific on vag-com or computer diagnose. 

Bearbeitet 22. Mai von TitusM