Golf IV 81 kW ASV consumes too much

Hello everyone,

My Golf IV (81 kW ASV, 2001, 140,000 km, re-imported from Italy) consumes approximately 5.8 liters per 100 km over the past 12 months. My Galaxy, which is almost twice as large and older (81 kW AFN, 1998, 290,000 km) with a nearly identical engine, also consumes 5.8 liters. The driving style is identical, primarily country roads and long distances, with a maximum speed of 120 km/h.

The engine requires significantly more fuel than the standard consumption of 4.9 liters, both in terms of proportion and compared to it. I specifically purchased the Golf because I expected a maximum of 4.5 liters of fuel consumption based on my driving style and profile.

I've already replaced the temperature sensor in the golf and reset the adaptation channels using VAG-Com, and I've checked the fuel start timing. Nothing has worked. The air filter is new. The car feels like it's being squeezed, and when overtaking, it's twice as responsive as the Galaxy. The ASV (presumably an exhaust system component) noise is completely clean. Even in the cold, it started immediately every time.

Has anyone got any ideas what's not right here, or how I can reduce the consumption? The car could use a little less power if it were more fuel-efficient.

Greetings
Richard

My ASV from Ibiza (year 2001, 150,000 km) also needs more than my previous one. Ibiza AFN, Year 1998.

I'm currently getting the ASV to about 650 km on a full tank, but only on short trips and with a modified ECU. The AFN could always be refilled around 5 liters.

I have already checked everything possible, including the air intake, magnetic valves, and any leaks, but nothing.

Has your golf also been performance-enhanced, if it also pulls twice as fast?

Richard wrote:

My Golf IV (81 kW ASV, 2001, 140,000 km, re-imported from Italy) over the last 12 months consumes approximately 5.8 liters per 100 km. I specifically bought the Golf because I expected a maximum of 4.5 liters per 100 kilometers based on my driving style and profile.

Has it always consumed so much since you've owned it?

Quote:

The car pulls like a clamp and is twice as nimble when overtaking as the Galaxy, regardless of speed. The car could definitely use a little less pulling power, if the fuel consumption is acceptable.

Chiptuning with Schluckspecht effect?
Run full-throttle logs (1500 – 4500 rpm, 3rd or 4th gear) from the MWB 8 and 11, where you should first generally check if the software is malfunctioning.

Then, log the MWB1+4 performance simultaneously within your typical operating range of RPM and load, to see if the spray initiation is correct (although I may not be able to provide a comparison with serial data, as my software is clearly PD-focused).

Hello Richard,

Please check the LLK (charge pressure hose) and the Gummischlauch (hose) that directly connects to the charger for any oil traces.

Best regards, Rainer

I don't know why, but the AFN engine in the Sharan/Alhambra/Galaxy is surprisingly economical!
I had the 90 hp AGR engine in the A3, and it consumed around 6 liters.
My Sharan with 426,000 km needs 6.1 liters per 100 km under brisk driving conditions, according to the MFA
And that, despite the fact that the timing settings were set correctly by chance, due to the lack of markings.
So, one can't really use it for comparison purposes with smaller Golf 4 or A3 models.
It seems that the fuel consumption of your ASV is realistic, as the VTG VP TDI in the A3 reportedly uses 0.3 L less fuel than the weaker TDI with a fixed turbocharger, according to the manufacturer's specifications.

Hello Ulf,

here are the LOGs. It took a while because I had to borrow a VAG-Com first. I hope the first LOG reaches a sufficiently high RPM.

Otherwise, please provide only the translation, no explanations.

While inspecting the lines, everything appeared original and untouched up to the control unit.

There is nothing remarkable on the LLK (Left Lateral Engine Mount) and the turbocharger hose (oil, leaks). The remaining tax hoses are also okay.

Thank you in advance
Best regards, Richard

Hello Richard,

I have removed the redundant data. Please read the instructions and then create the logs.

It's about what should be logged, but please don't do something like stopping at the traffic light twice. This has already been described 123424 times here. So again: Full throttle from 1500rpm to 4000rpm, for example, in 3rd gear. Okay.

Greetings, Rainer

Hello Rainer,
hello Ulf,

I have access to VAG-Com again today, Sunday. I hope I have now correctly understood the instructions for the "Full Throttle Log" procedure. Today, I chose a main federal highway and drove the car from 1,200 RPM to full throttle and then back down, using 4th gear. Speed increased.

I have recorded the measurement blocks 3, 8, and 11, and in a second run, I have additionally recorded 1 and 10. I hope the sampling rate is sufficient. For comparison, I also did this with my old Galaxy using the measurement blocks 3, 8, and 11.

Best regards, Richard

I was able to access VAG-Com again today, Sunday.

Richard wrote:

has regained access to VAG-Com today, Sunday. I hope I have now correctly understood the instructions for the full throttle log. Today, I chose a federal highway and drove the car from 1,200 RPM to full throttle and then back down in 4th gear. Speed increased. I have recorded the measurement blocks 3, 8, and 11, and in a second run, I have additionally recorded 1 and 10. I hope the sampling rate is sufficient. For comparison, I also did this with my old Galaxy using the measurement blocks 3, 8, and 11.

Look, seeing the pictures makes it immediately fun
Regarding the ASV, I don't notice anything particularly noteworthy. The starting pressure seems to be controlled quite cleanly. However, the LuMa/LD ratio seems a bit low, as if there might be a bottleneck somewhere in the gas pathways. Possibly a thick layer of EGR (Exhaust Gas Recirculation) residue in the intake manifold, which would also fit well with the relatively wide-open VTG (Variable Timing Gear).
"Regularly tuned" "as it should be methodically" he probably isn't. If so, then only using the 10c approach with pump voltage, or with a power connector (both of which would require further explanation for the wide-open VTG), but I don't know the standard values for pump voltage.
Does it noticeably smoke when accelerating to full throttle?
Is he a show-off (spoiler, loud music system, etc.)?
Are the brakes functioning properly, or are the rims of one axle significantly different in temperature after a few kilometers of driving?


The AFN has a 99% chance of having a large air leak, which is evident from the high LuMa/LD ratio, the relatively closed VTG at full throttle, and the tendency for the boost pressure to drop.
Likely, he experiences quite a bit of backpressure when giving full throttle and increasing the boost pressure.
I would not delay repairing the leak, because it could eventually cost you the entire load, and if things go badly, even the whole engine.

Hello Ulf,

Thank you very much for the quick and interesting response.
I've also tried to create a rhyme from the curves.

I will be seeing the ASV again in 2 weeks. I will then remove and inspect the intake bridge. Incidentally, it is a standard car with no modifications (except for the air conditioning, but that is working). I couldn't find any tuning boxes or resistors either. Engine and brakes are free.

Both also have a HJS filter.

At the AFN, it's actually the case that it's been producing a strong amount of smoke when accelerating (despite the HJS filter) for some time. I had previously attributed this to the old injectors. I quickly checked and scanned the entire intake system for leaks. Everything looks brand new. The LLK (turbocharger) is also completely dry. I don't feel any air leaks anywhere. What size leak would you consider to be significant? I suspect the hose for the boost pressure. "There are some parts that are a bit worn, and I'll be replacing them this week."

Greetings
Richard

Richard wrote:

By the way, both have a HJS filter.

If the one for the ASV creates more backpressure than the AFN version, or if something has been plugged or welded (?) into it, that could also explain the slightly reduced air mass flow and increased fuel consumption.

Quote:

In reality, the AFN actually produces a significant amount of smoke when accelerating (despite the HJS filter). . . What size leak would you consider to be significant?

The LuMa data is approximately 50% higher than the LD – if that's the case, because the LuMa actual value is usually also at the maximum of the diagnostic scale (1275 mg/stroke)! D.h. wenn LMM, seine Kalibrierungskurve und die Kalibrierung der Diagnosedaten im MSG serienmäßig sind, dann gehen zusätzlich durch die Lecks etwa die Hälfte dessen verloren, was der Motor als Volumenstrom aufnimmt – mindestens!
Since a 4-cylinder engine, when over-revving, constantly sucks in through one open intake valve, one could roughly estimate the leak area as being approximately half of an intake valve.

Quote:

I suspect the hose for the boost pressure more. It's a bit worn in some places, so I'll be replacing it this week.

Do you mean the thin hose for the MSG? Even if you completely disconnect it from the nipple, it won't allow even a tiny amount of air to flow through, which is enough to explain the diagnostic values.

Hello everyone,

Latest update:

Golf IV, ASV:
1. Air filter and LMM (Pierburg) replaced, result on my 150 km weekend reference route (150 km, 70% country road, 70% cruise control, mostly 100 km/h): 4.8 l/100 km. The car felt noticeably different than with the old LMM!!!
2. Remove the intake manifold, removing approximately one cup of carbon from the AGR and intake manifold (the passage from 50mm to 30mm at the AGR flange was reduced), install a special seal (without a hole in the middle) in front of the AGR, result: 5.0 l/100 km !!!?, The car pulls powerfully, especially in the lower range (even better than with the old O2 sensor),
3. Special seal from AGR re-installed, result: 5.2 l/100 km, test drive is in the attached log file on page 2. View the spreadsheet.

Consequence: Reinstall AGR Special Seal.
Questions: How can it be that a free engine, under the same driving conditions on my reference route, requires more than a tuned engine? Are there any ideas on how I can still achieve around 4.5 l/100 km despite the adaptation channels and nozzles?

Galaxy, AFN:
1. Air filter to engine intake system: Vacuum test completed, result: 100% airtight! What else could be the cause of the excessively high actual air mass?
2. Eine spezielle Dichtung wurde in der AGR eingebaut. Die Lufteinlassbrücke war noch nicht unten (wie ich mit dem Finger fühlen und mit einem Spiegel sehen konnte, ist sie weitgehend frei). Wo könnte das Rauschen beim Beschleunigen sonst noch herkommen (der Luftfilter ist in Ordnung, möglicherweise)? Nozzles, but it's running smoothly and requires relatively little) ?

Calibration run on the reference track and log file (with the new LMM) will be next weekend.

Best regards, Richard

Please check the VCDS serial number in the profile.

Richard wrote:

Questions: How can it be that a free motor requires more at the same driving style on my reference track than a tuned one?

Take a look at the TV (Throttle Valve) graph in the MWB11 logs for both: With free throttle valve positions with about 10% more air mass flow, the VTG (Throttle Valve Geometry) must remain significantly more closed to build up the desired boost pressure -> this results in more exhaust gas resistance, which reduces the engine's efficiency.

Quote:

Are there any ideas on how I can still achieve around 4.5 l/100 km (using adaptation channels, injectors, etc.)?

Reducing the boost pressure target in the partial load range by approximately 10% (= a chiptuning intervention) would bring you back to approximately the previous state.

Quote:

Galaxy, AFN: Suction system from air filter to engine: completely sealed! What else could be the cause of the excessively high actual air mass? . . . Where else could the

leak be coming from? For example, a leak in the intake manifold, between the intake manifold and the K-sensor. Or, from an elastic crack that has not opened due to insufficient testing pressure.