It's not helpful that there is conflict between the FAA advisory on fuels for certain engines (as posted by Brian in post #10), the ExxonMobil World Jet Fuel specs brochure, and the P & W Canada, Service Bulletin.
From the FAA advisory - "Diesel Fuel approval limited to TPE331-1-101Z engine only, and usage at ambient temperatures above +15°F.
Aviation gasoline MIL-G-5572D, Grade 80/87, not in excess of 1000 gallons per 100 hours of operation, may be used for emergency fuel operation.
As regards the ExxonMobil World Jet Fuel specs brochure (post #23)... the word "diesel", cannot be found anywhere in that document...
ExxonMobil do have a bold and unambiguous statement (page 41) that, "(ExxonMobil) does not support or approve the use of automotive gasoline or diesel fuel in piston engine powered aircraft".
And from the P & W bulletin, as linked in post #13, above...
CAUTION: ALTHOUGH DIESEL AND HEATING FUELS ARE CHEMICALLY SIMILAR TO JET FUELS, THEIR COLD FLOW, VISCOSITY AND FREEZING POINT
CHARACTERISTICS ARE SPECIFICALLY CONTROLLED DURING REFINING TO A LEVEL GENERALLY NOT SUITABLE FOR USE IN AIRCRAFT. (in bold, capitals, and very large print, as in the original).
A temperature limitation of +15°F makes diesel fuel, a tightly conditions-restricted fuel, once you get airborne.