Verbrauchsoptimierung via Spritzbeginn: Soft- oder Hardware? | Posts 48+

Okay, I understand. Please provide the text you would like me to translate from German to English.

The behavior with a different coolant temperature depends heavily on the specific engine control unit (ECU).

Best regards, Rainer.

Hello,
Even though the topic is old, it's the best fit for my question.
Does the ALH engine (90 hp, VEP37) also have the so-called "fuel consumption optimizing" humps in the power curve at 2000 rpm and 2500 rpm?

I have conducted various test runs and am unable to determine corresponding injection start values for these speed ranges, even under different load conditions.

"My car has been consuming significantly more fuel on the highway for about two years now. I often use cruise control at 120 km/h and used to get around 4.7 liters per 100km, but today it's closer to 5.5 liters. These values are calculated based on trips over 500km per day. Under normal conditions without using the highway, I easily achieve excellent fuel consumption figures of 3.8-4.5 liters per 100km. I've already logged and tested everything mentioned in this forum – everything seems normal. (I checked the mass airflow sensor, boost pressure, injection timing, intercooler temperature, and intake passages). The car is a Golf 4 ALH with 350,000 km on it. The only modification from stock is a slightly reduced air mass setting, but that's been in place for years."

best regards
Andreas.

Quote:

has the ALH

.
Which one? Please provide the VAG part number for the control unit and the software version.

Without looking up: In 99% of cases, yes. Simply drive in the highest gear on a flat surface at approximately 95 km/h (indicated speed) and compare when the fuel injection starts at 70 km/h and 105 km/h.

Best regards, Rainer.

Hello Rainer,
I hope I'm providing the correct numbers now.
VAG 038 906 018 AE
Software 1.9L R4 EDC G430SG - 2103.

Here's another thought I have about the injectors. They are likely worn out, which means they now allow more fuel through than before, even with the same driver demand. This excess fuel is what triggers the ESP to shut off. Alternatively, perhaps it releases a smaller amount of fuel, allowing me to bypass the area in the engine map between idle and those specific "humps" I mentioned?
(The noise regulations present a consistent picture, so I hadn't given much thought to this aspect yet.)
I also tried to set the static injection start point to the early tolerance limit. Unfortunately, the actual value drops below the target by 3 degrees continuously during idle until it reaches the target value again at 2500 rpm – which is exactly where I need it.

best regards
Andreas.

Quote:

Another thought I have is about the injectors. Certainly, they are worn out, which means that they now allow more fuel through for the same driver demand. This excess amount triggers the ESP to shut off - or does it release a smaller amount, and therefore do I drive in the engine map area between idle and those aforementioned peaks?

"That's correct, but the nozzles would have to be quite worn out for that to happen. From my own experience with an AHF (nozzle replacement was over 200,000 km ago), fuel consumption decreased by about 0.5 liters per 100 km."
It appears that nozzle wear plays a significant role.
The wear and tear on the fuel injectors, in turn, is highly dependent on the type of fuel used, where the "cleanliness" of specific gas stations has a more significant long-term impact than particular brands.

Best regards, Rainer.