AHF to ASV Control Unit Replacement

Hello everyone,

I have an AHF engine with a faulty control unit (water damage). I also have a control unit from the ASV, which is its successor. Besides a few "minor" things, the biggest difference is the emission standard: Euro2 for the AHF and Euro3 for the ASV, which also affects the injectors used.

ASV - DSLA150P357 with a pressure opening of 220/300 BAR.
AHF - DSLA150P520 with a pressure relief setting of 190/300 BAR.

The pre-injection pressure deviates by 30 bar. Do you think I can use the ASV control unit? The nominal speed is specified as 4000 rpm for the ASV and 4150 rpm for the AHF, so the characteristic map is different. However, the pump is exactly the same for both engines.

My question is whether I should expect any kind of wear and tear on the nozzles if they are deviating from their specifications, or whether this is "just" a cosmetic issue related to the finer pre-atomization of the diesel fuel needed to meet Euro3 standards, which I don't actually need.

Gentlemen!

Surely someone among you must have an opinion on this; where else on the internet, if not here, can you find those enlightened individuals who are passionate about self-improvement?

The pump voltage is different, and as a result, the entire control unit is usually shifted somewhat.

Besides that, the ASV doesn't have 357 injectors, but rather DSLA150P873 injectors. These have slightly smaller injector nozzle holes compared to the 520 injectors used in the AHF/AFN engines.

If you install the STG (throttle body) from an AHF engine, you may need to readjust the fuel quantity (offset) at the pump or using a diagnostic tool to achieve a stable idle with a fuel injection rate of 4-6 mg per cycle. Additionally, there might be a slight increase in power output in the higher RPM range.

Unfortunately, I don't have a control unit file from AHF to check whether the pump voltage actually differs.

Thank you, but it's actually the opposite .

I have the AHF motor and want to install the ASV control unit.
According to the part numbers from both Bosch and Volkswagen, the pumps are identical.
Thank you for the correction regarding the nozzle sizes.

Indeed, the ASV reaches its peak performance at 4000 RPM according to the motor data, while the AHF achieves its peak performance at 4150 RPM.

The block and pistons are the same. According to AKTE, they are not (if you consider the engine block as a group with one part number). However, when breaking down the engine block into its components, you can see that the part number of the bare engine block without the crankshaft is the same for both ASV and AHF engines (as well as the crankshaft, connecting rods, bearings, flywheel, cylinder head, etc.). The pistons, however, have different part numbers.

However, the online MAHLE catalog provides a solution. For the AHF and ASV engines, the same MAHLE part numbers are used for the MAHLE replacement parts; in this case, it's essentially only the injectors that differ.

You described the case of converting from ASV to AHF. How about the reverse: an ASV engine with an AHF motor?

Quote:

I have the AHF motor and want to install the ASV control unit. According to the Bosch and Volkswagen part numbers, the pumps are identical. Thank you for the correction regarding the nozzle sizes.

I understood it that way anyway.

The AHF is essentially an AFN engine. It has injectors with nozzle holes of 0.205 mm. The ASV is a further development that meets the Euro3 emission standard. Therefore, injectors with slightly smaller nozzle holes (approximately 0.200 mm) are used.

Conclusion: It will probably work, but you need to be aware that legally, you are not allowed to operate the vehicle in public roads. Why? Because there is no emissions test certificate for this combination of EU2 and EU3 engine components.

Quote:

You described the case of ASV to AHF; what about the reverse? An ASV transmission with an AHF engine

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That's exactly what was meant. The ASV achieves the same 81 kW with a higher pump voltage, provided the pump is the same. This is because, on one hand, the nozzles have smaller boreholes, and on the other hand, the rated power speed is lower.

The maximum speed will not increase and may even decrease. While the nozzle bores are larger, the ASV TCU (Transmission Control Unit) is programmed to provide the torque required for a nominal power output at 4000 RPM. One could calculate which factor has more influence, but I believe it's faster to determine this experimentally.


Caution: Do both control units have the same WFS generation? The ASV was available with both WFS II and WFS III.

Based purely on the probability of the engine control units (ECUs) used in both engines, this project is highly unlikely to work as intended, or at least not easily.

Just install the original control unit and it's all good.

If all else fails, I have an ALH control unit here that should work with the data from the AHF (please provide the part number/software version of the original).

Best regards, Rainer.

Both engine control units are using the Immo2 system.

I performed the engine swap, and the engine is running smoothly. However, there's a slight "jerk" between 1500 RPM and 903 RPM when decelerating (idling without being in gear while stopped). Otherwise, no other issues have been detected.