logo elektroda
logo elektroda
X
logo elektroda
Advanced Search
logo elektroda

[Solved] vw / passat / b6 2.0TDI CBAB - High fuel consumption passat b6 2.0 TDI CBAB

karl-88 33351 18
Best answers

Why is my Passat B6 2.0 TDI showing 5.5–6.5 L/100 km on the computer but actually using about 9–10 L/100 km, and why is oil getting into the engine oil?

The high consumption was caused by a clogged DPF; after it was dealt with, the fuel consumption matched the computer readings and fuel no longer diluted the oil [#17387236] Before that, suggestions included checking for fuel leaks, especially around the fuel system, and verifying the air mass meter with actual expected vs delivered airflow values rather than just “it is OK” on the tester [#17324805][#17332151] Another likely cause mentioned was overfueling injectors, such as worn nozzles or broken springs, and checking the injectors for regeneration [#17358484] Compression tests showed the pistons and rings were OK, which helped rule out major mechanical damage [#17335524]
Generated by the language model.
ADVERTISEMENT
Treść została przetłumaczona polish » english Zobacz oryginalną wersję tematu
Report a violation of the law
| New topic
  • #1 17324686
    karl-88
    Level 10  
    Posts: 12
    Rate: 21
    Hello,
    I have Bassata b6 2.0 TDI CBAB I have a burning problem.
    The computer shows fuel consumption of 5.5-6.5L while in reality fuel consumption is about 9-10l / 100km.
    I went to a mechanic and examined DPF and it is only 3% full.
    The EGR and exhaust gas cooler are removed together with programming from a computer.
    Please help . Thanks in advance
  • ADVERTISEMENT
  • #2 17324805
    decybel91
    Level 43  
    Posts: 7987
    Help: 1020
    Rate: 4191
    Logic suggests that fuel is escaping (leaking). Often at the fuel cooler.
  • #3 17324908
    karl-88
    Level 10  
    Posts: 12
    Rate: 21
    Thanks for the answer, of course, I will check, but unfortunately it doesn't smell of oil anywhere

    Added after 7 [hours] 9 [minutes]:

    Unfortunately, my car does not have a fuel cooler because it is on a comon rail. I also noticed that oil is coming.
    The mechanic checked the injection molding machine and said it was ok. Help me please because I have no more ideas.
  • #4 17331684
    karl-88
    Level 10  
    Posts: 12
    Rate: 21
    Can anyone help me?
  • #5 17331732
    iron64
    Level 41  
    Posts: 6197
    Help: 648
    Rate: 312
    Did you check the flow meter?
  • ADVERTISEMENT
  • #6 17332021
    karl-88
    Level 10  
    Posts: 12
    Rate: 21
    Yes, the flow meter has been checked

    Added after 2 [minutes]:

    the mechanic said the flow meter is good
  • #7 17332151
    iron64
    Level 41  
    Posts: 6197
    Help: 648
    Rate: 312
    Oh come on. He said? Let him give the parameters. Expected and delivered air mass and not said.
  • #8 17332251
    karl-88
    Level 10  
    Posts: 12
    Rate: 21
    he checked his parameters on the computer and said that they are ok and what should these parameters be ????
  • #9 17332537
    iron64
    Level 41  
    Posts: 6197
    Help: 648
    Rate: 312
    iron64 wrote:
    Expected and delivered air mass

    The computer gives expectations regarding the revolutions and load and also gives how much air it gets.
    But I see that your knowledge is quite small and I suggest changing the mechanics and let another take care of it. No offense mate, but some things are better to give to someone who knows about it.
  • #10 17332631
    karl-88
    Level 10  
    Posts: 12
    Rate: 21
    Is it possible for you to recommend me if you obviously know someone from the Miechów area near Krakow ????
  • ADVERTISEMENT
  • #11 17332813
    cooltygrysek
    Conditionally unlocked  
    Posts: 2813
    Help: 131
    Rate: 530
    karl-88 wrote:
    . I also noticed that oil is coming.


    We don't know at what rate the oil arrives. A small amount of oil is usually due to a clogged DPF. The arrival of more oil may indicate damaged rings or a broken piston or pistons caused by the most likely pouring injection.

    karl-88 wrote:
    The mechanic checked the injection molding machine and said it was ok


    Under the computer will not show the actual dose. Similarly with DPF. Depends on driving style (city driving, traffic jams) and fuel quality. Please check if it blows strongly from pneumothorax, which will exclude damage to the rings and the piston, however, this is not a reliable control as it can blow through leaking valve seals. Nevertheless, a skilled mechanic will recognize the symptoms by pneumothorax. Another and basic diagnosis is checking compression in cylinders.
  • ADVERTISEMENT
  • #12 17333384
    karl-88
    Level 10  
    Posts: 12
    Rate: 21
    ok thanks for the info, when it comes to oil it came about 4mm on 800km
  • #13 17335347
    cooltygrysek
    Conditionally unlocked  
    Posts: 2813
    Help: 131
    Rate: 530
    It's a lot. Oil for immediate change because it is diluted.
  • #14 17335524
    karl-88
    Level 10  
    Posts: 12
    Rate: 21
    After testing the pressure in the cylinders, it turned out that the pistons and rings are ok. The mechanic has the same car and 2.0 TDI engine on pump injections with increased power to 160HP and stated after driving my car that it has better acceleration and is stronger. Analysis on the computer showed that the car has 420Nm. Is it possible that in this car chip tuning could be uploaded and therefore it has such combustion and this oil is added (oil in oil)
  • #15 17335940
    E8600
    Level 41  
    Posts: 8861
    Help: 525
    Rate: 2474
    Everything is possible in diesel. I know the case where the turbine was overclocked and blew as much as it should and the injection was pouring. Despite this, the car had a shoe - until and the patient is an Audi A4 B5 with 1.9 TDI.

    How long has your friend got this car? Have recently bought because maybe in the engine there is a doctor instead of oil that good pressure has come out. And with combustion they are probably injections to be replaced.
  • #16 17336012
    karl-88
    Level 10  
    Posts: 12
    Rate: 21
    Car not long ago bought, so I don't know what could have been done before. I changed oil for a new one and made only 1000 km on this oil
  • #17 17358484
    cooltygrysek
    Conditionally unlocked  
    Posts: 2813
    Help: 131
    Rate: 530
    So we know something. Probably the injection is pouring. The reasons can be two, either developed atomizer nozzles or broken springs. Please give injections to check or regenerate. There is another third possibility, namely the possibility that the previous owner installed other injections to increase the power. As for chip tuning, I doubt it because it should display relevant software data on the computer.
  • #18 17387236
    karl-88
    Level 10  
    Posts: 12
    Rate: 21
    Hello
    The car was made, the reason for such combustion was clogged DPF after its elimination, the combustion is like on a computer and of course the fuel does not get into the oil.
    Thanks in advance for your help.
  • #19 17387248
    karl-88
    Level 10  
    Posts: 12
    Rate: 21
    Hello
    The car was made, the reason for such combustion was clogged DPF after its elimination, the combustion is like on a computer and of course the fuel does not get into the oil.
    Thanks in advance for your help.

    Added after 4 [minutes]:

    Hello
    The car was made, the reason for such combustion was clogged DPF after its elimination, the combustion is like on a computer and of course the fuel does not get into the oil.
    Thanks in advance for your help
| New topic
Report a violation of the law

Topic summary

✨ The discussion revolves around a Volkswagen Passat B6 2.0 TDI CBAB experiencing significantly higher fuel consumption than indicated by the onboard computer. The user reports actual consumption of 9-10L/100km, while the computer shows 5.5-6.5L. Initial checks included the DPF, which was only 3% full, and the EGR system, which had been removed. Various suggestions were made, including checking for fuel leaks, examining the flow meter, and assessing the condition of the injectors. Ultimately, it was determined that a clogged DPF was the cause of the excessive fuel consumption, which was resolved after its elimination, leading to normal fuel consumption readings.
Generated by the language model.

FAQ

TL;DR: Owner saw 9–10 L/100 km despite 5.5–6.5 shown; "reason for such combustion was clogged DPF." Fixing DPF restored consumption and stopped oil dilution on a Passat B6 2.0 TDI CBAB. [Elektroda, karl-88, post #17387236]

Why it matters: For Passat B6 2.0 TDI CBAB owners with high fuel use and rising oil, this FAQ shows what to check first.

Quick Facts

Why does my Passat B6 2.0 TDI CBAB show normal consumption on the computer but use much more fuel?

A clogged DPF can trigger frequent post-injections and higher backpressure, raising real fuel use. In this case, addressing the DPF brought indicated and actual consumption back in line and stopped oil dilution. Check DPF status and regeneration behavior before chasing other causes. [Elektroda, karl-88, post #17387236]

Can a clogged DPF raise my oil level?

Yes. Extra post-injection during regens can wash fuel past rings, diluting oil and raising the dipstick level. “Oil for immediate change because it is diluted.” Change oil, then resolve the underlying cause to protect the engine. [Elektroda, cooltygrysek, post #17335347]

My scan shows the DPF is only a few percent “full.” Could it still be restricted?

Yes. Percentage readings can mislead due to driving style, idling, and fuel quality effects. Ash accumulation or uneven soot loading can still restrict flow. “Depends on driving style and fuel quality.” Consider backpressure testing or professional inspection if symptoms persist. [Elektroda, cooltygrysek, post #17332813]

Can injectors overfuel even if the scan tool says they’re OK?

Yes. Balance or correction values can look normal while injectors mechanically overfuel. Worn nozzles or broken springs can cause this and increase consumption. “Either developed atomizer nozzles or broken springs.” Have injectors bench-tested or regenerated if suspected. [Elektroda, cooltygrysek, post #17358484]

Could a fuel leak be causing my high consumption?

Yes. Inspect lines, connections, and components for wetness or diesel odor. “Logic suggests that fuel is escaping (leaking).” On some variants, leaks occur at the fuel cooler; check if your car has one fitted. [Elektroda, decybel91, post #17324805]

What mass air flow (MAF) values should I compare?

Use a scan tool to compare specified versus actual air mass at set RPM and load. Don’t accept vague “it’s fine.” “Expected and delivered air mass.” Log both channels during a controlled road test to spot airflow issues. [Elektroda, iron64, post #17332537]

How can I check if a chip tune is installed?

Read ECU software identification and version with a scan tool. Non-stock maps often show altered software data. “It should display relevant software data on the computer.” Some tools can also compare checksums or read the flash. [Elektroda, cooltygrysek, post #17358484]

Can a tune alone explain high consumption and rising oil level?

Not necessarily. In this thread, the issue was a clogged DPF, not software. After fixing the DPF, consumption matched the display and oil stopped rising. Address hardware restrictions before blaming calibration. [Elektroda, karl-88, post #17387236]

How do I quickly triage high fuel consumption on a CBAB?

Try this: 1) Check crankcase blow-by at the breather and watch for rising oil. 2) Perform a compression test to assess rings and pistons. 3) Evaluate DPF health beyond a percentage; consider how city driving skews readings. “Another and basic diagnosis is checking compression.” [Elektroda, cooltygrysek, post #17332813]

What should I do if my oil level rises on the dipstick?

Stop extended driving and change oil immediately to protect bearings and turbo. “Oil for immediate change because it is diluted.” Then diagnose causes like DPF-related regens or injector overfueling to prevent recurrence. [Elektroda, cooltygrysek, post #17335347]

Does the CBAB common-rail have a fuel cooler that can leak?

Some cars lack a fuel cooler in this configuration. The OP’s CBAB had none fitted. Confirm your vehicle’s parts layout by VIN or catalog before hunting cooler leaks. [Elektroda, karl-88, post #17324908]

How can I tell if rings or pistons are damaged versus valve seals?

Check blow-by from the crankcase vent to assess ring sealing, then confirm with a compression test. Excess blow-by suggests ring or piston issues, but leaking valve seals can mimic symptoms. An experienced mechanic can judge by results. [Elektroda, cooltygrysek, post #17332813]

How much did the oil level rise in this case?

About 4 mm over 800 km. That’s a clear warning of fuel dilution during the fault window. Use it as a benchmark to recognize similar symptoms early. [Elektroda, karl-88, post #17333384]

What was the final fix and outcome in this thread?

The DPF was clogged and then removed. Afterward, real consumption matched the computer display, and fuel no longer entered the oil. The owner confirmed normal operation. [Elektroda, karl-88, post #17387236]
Generated by the language model.
ADVERTISEMENT