I see that the replies here are old but I stumbled into this place and thought I'd share my experiences since there's not a lot of information about this remarkable car.
When I went to buy my first car I wanted something practical with good mileage. My father recommended a Nissan as he liked the pickups.
At the dealer they had just received a red and a green-gold 1985 Nissan Sentra diesel with the CD17 engine. I see the epa now has the mileage of this model at 38/44
. I recall though that both numbers were over 40.
I bought the green-gold one. I recall that it was priced at $2000 more than the gasoline model but I figured the fuel savings would make up the difference.
The car routinely got 47 mpg on average in city driving. Never less. I did not do too many road trips but when I did it always got 55mpg.
It had a California emissions system and did not smoke. After befriending a retired petroleum fuel engineer, I would try to find out which stations had diesel with good cetane ratings, not something they list on the pump. She sold me some special diesel additive she had formulated, which added power and zing, reduced noise (not that it was very noisy it rather purred like as asthmatic kitten) and upped the mileage a bit.
The dealer was completely useless and would constantly screw things up, overcharge, and be helpless. I took a class in diesel mechanics and learned to rebuild the injectors (you can use Mercedes parts for some things and they are cheaper) and replace the timing belt (not easy). There was also easier things like replacing the fuel filter every 5 years, the air filter once a year, and making very sure to change the oil regularly. This is important on a diesel or the sulfates in the fuel turn to sulfuric acid in the oil with condensation in the engine and destroy the engine. Eventually I needed a new injection pump. Nissan wanted $2500 for a new one and was not equipped to rebuild it themselves. I had a Mercedes mechanic rebuild it and he was quite upset when Nissan charged him $700 for a single critical O-ring.
I kept the car until 1999 when I moved overseas. At that time I could not sell it and ended up giving it away. It was a very very well engineered car, unlike anything that has been seen. And of course the fuel efficiency was excellent. When people complain about mileage, I know for a fact we are capable of building efficient cars. After all this was 1985 and it was an inexpensive economy car. It does not require elaborate technology to get great mileage, only excellent engineering.