Is there a Hydrogen Pump for VW Jetta TDI?

Totally false, for one hydrogen is a gas and like propane powered vehicles does not require a pump to move the fuel only a regulator to keep the pressure steady, second without some serious changes to your engine and vehicle it will not run on hydrogen alone the way it is. Conversion kits are starting to come available but very expensive depending on the vehicles design. Just research vehicle hydrogen conversion on the net and you will see. The only way to make your Volkswagen TDI use less fuel is threw electronic tuning of the ECM different injectors, air intake, manifolds and cylinder head mods again this is expensive my advice for you and your TDI, keep it maintained and enjoy the fuel mileage your getting your still better than any gas engine in its class.