Isuzu 4JA1L engineThe Isuzu 4JA1 L engine is a 2. 5 liter, 4 cylinder diesel engine widely used in Isuzu utility vehicles and light commercial trucks. In South Africa, this engine typically fits the following vehicles: Isuzu KB D Max (older models) 20042012 Isuzu KB250 models (single cab, double cab, and extended cab) Often labeled as KB 250 LE Fleetside Base models Isuzu NPR N Series Trucks Light duty trucks like the Isuzu NLR or NPR 250 (used in commercial transport