Airtronic D2: Eberspächer Diesel Heater

Hello everyone,
I know this might not be the right department to ask, but maybe someone here can still help.
I installed an Eberspächer Airtronic D2 diesel air heater in my Sprinter.
Yesterday, the diesel pump broke. Since I had a spare one from Webasto lying around, I installed it today. The heater starts up immediately again. But: it's smoking like crazy. Could it be that the Webasto pump is too large and therefore pumps too much diesel into the heater?
Perhaps someone here has one of those.

Best regards, Mäffie.

Eberspächer already offers various dosing pumps for different diesel heaters.
If your engine is running too rich, the combustion behavior can be noticeable and likely problematic.
You can measure the amount of fuel dispensed by pumping the fuel that has been dispensed up to the point where the heater shuts off into a measuring container. After 110 seconds, the heater will shut off without diesel if it doesn't ignite, and you can measure the amount.

Okay, so I've chosen one out of the 3 D2 types.
The target values for diesel quantity are set as follows: 3.7 cc at a minimum of 11 volts, up to 4.3 cc at 13 volts, within a shutdown interval of 110 seconds.
The water-cooled diesel heater has a capacity of 5 kW, which is more than double the amount of the other one. I'm not sure what the capacity of yours is.
I still have an Eberspächer heater; I could potentially have it modified to suit your needs.