The Isuzu 1.9 diesel engine is widely recognized for its impressive fuel efficiency, with real-world and test figures varying according to driving conditions and vehicle configuration.
Owners regularly report average fuel consumption figures between 11.7 km/l and 13 km/l (approximately 8.6 to 7.7 L/100km) in mixed and open-road driving[1]. Extensive user data shows averages around 12.0 km/l for manual double-cab variants, with best-case results reaching up to 13.2 km/l[1].
In controlled economy tests, the latest Isuzu D-Max 1.9 Ddi Double Cab 4×2 manual recorded an exceptional 5.1 L/100km (or 19.4 km/l), achieved during a steady extended trip at 100 km/h[2][4]. More typical mixed-use testing, including urban and off-road conditions, delivers results around 8.8 L/100km (about 11.4 km/l)[3]. Short open-road trips show similar real-world results, for example, 11.8 km/l (8.2 L/100km)[5].
Long-term testing in the UK with a D-Max DL20 Double Cab 4×4 (manual transmission) recorded average consumption of 33.3 mpg (8.5 L/100km or 11.8 km/l), close to the official figure of 33.6 mpg (8.4 L/100km)[6].
The Isuzu 1.9 Ddi engine features advanced turbocharging and direct injection, contributing to its low consumption and making it a strong choice for drivers prioritizing efficiency alongside reliability and low running costs[4].