I'm not sure what injection sys. is in there either. But, I imagine there has to be at least a little fuel coming out of the injectors during cranking, or else whats going to ignite?
If you have huge amounts of fuel coming out of there, then I would suspect the injection. But...maybe with all that dust, the air filter is clogged and its not getting enough air... Or.. maybe during the bumpy ride, the ignition timing is off. (which makes me want to urge you to inspect all of the ignition wires before you take anything else apart)

...my (edited) two cents

(for what they are worth)

-Larry

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It is a truism that almost any sect, cult, or religion will legislate its creed into law if it acquires the political power to do so. Robert A. Heinlein


09 Jetta TDI
1985 300D