1991-1998 Isuzu Bighorn (SUV) 3.1 DT (125 Hp) Automatic

The Isuzu Bighorn, known as the Isuzu Mu in some markets, was a mid-size SUV produced by Isuzu between 1991 and 1998. This generation, internally designated as the UBS series (and often referred to as the first generation Bighorn), aimed to provide a robust and capable vehicle for both on and off-road use. The 3.1 DT variant, equipped with a 3.1-liter turbocharged diesel engine and a four-speed automatic transmission, represented a significant offering within the Bighorn lineup, targeting buyers seeking a blend of practicality, towing capacity, and relative ease of driving. It was primarily sold in Japan, Australia, and parts of Europe, and was not officially offered in the North American market.

Technical Specifications

Powertrain & Engine Architecture

The heart of the Bighorn 3.1 DT is the 4JG2 engine, a 3.1-liter (3059 cc) inline-four cylinder diesel. This engine featured a cast iron block and aluminum cylinder head, a common configuration for diesel engines of the era. The 4JG2 utilized a turbocharger with an intercooler to boost power output to 125 horsepower at 3600 rpm and 275 Nm (202.83 lb-ft) of torque at 2000 rpm. The engine employed a direct injection system, delivering fuel directly into the combustion chamber for improved efficiency and power. While later iterations of Isuzu diesels would adopt common rail technology, the 4JG2 used a more traditional mechanical injection system. The four-speed automatic transmission, while providing convenience, was a relatively simple unit designed for durability rather than outright performance. It was a conventional hydraulic automatic, lacking the electronic controls found in more modern transmissions.

Driving Characteristics

The Bighorn 3.1 DT Automatic offered a comfortable, if not particularly sporty, driving experience. The automatic transmission, while smooth in operation, did detract from the engine’s potential. The gear ratios were geared towards fuel economy and towing capacity, resulting in somewhat sluggish acceleration. Compared to the five-speed manual transmission available on other Bighorn models, the automatic version felt noticeably slower. However, the ample torque of the 4JG2 engine provided sufficient power for everyday driving and hauling loads. The all-wheel-drive system, typically part-time selectable 4WD, offered enhanced traction on slippery surfaces and moderate off-road capability. The vehicle’s weight, at over 2000 kg, contributed to a feeling of solidity but also limited agility.

Equipment & Trim Levels

The Bighorn 3.1 DT Automatic typically came equipped with a reasonable level of standard features, though specifics varied depending on the market. Common features included power windows, power steering, air conditioning, and a basic audio system. Interior upholstery was generally cloth, with optional leather available on higher trim levels. The dashboard layout was functional and straightforward, prioritizing usability over aesthetics. Optional extras could include a sunroof, upgraded audio systems, and alloy wheels. The 3.1 DT Automatic generally sat in the mid-range of the Bighorn lineup, offering a step up in terms of engine size and refinement compared to the base models, but lacking the luxury features of the top-of-the-line trims.

Chassis & Braking

The Bighorn utilized a body-on-frame construction, providing a robust and durable chassis. The suspension consisted of independent double wishbones at the front and a multi-link setup at the rear. The rear brakes were drums, a cost-saving measure common in this class of vehicle, while the front brakes were ventilated discs. Stabilizer bars were fitted to both the front and rear axles to reduce body roll during cornering. The steering was a recirculating ball system, providing a relatively heavy but precise feel. The tires, typically 245/70 R16, were chosen for a balance of on-road comfort and off-road traction.

Market Reception & Comparison

The Isuzu Bighorn 3.1 DT Automatic was generally well-received as a capable and reliable SUV. Critics praised its robust construction, comfortable ride, and strong diesel engine. However, the automatic transmission was often criticized for its lack of responsiveness and impact on fuel economy. Compared to other SUVs in its class, such as the Mitsubishi Pajero or Toyota Land Cruiser, the Bighorn offered a more affordable alternative, but lacked the same level of refinement or brand prestige. The 3.1 DT variant offered a good balance between performance and fuel efficiency, making it a popular choice for buyers who needed a vehicle for both work and leisure.

Legacy

The Isuzu Bighorn, and specifically the 3.1 DT Automatic variant, has developed a reputation for durability and reliability. The 4JG2 engine is known for its longevity, and with proper maintenance, can accumulate high mileage. In the used car market, these vehicles are often sought after by those looking for a dependable and capable SUV at an affordable price. While parts availability can be a concern in some regions, the Bighorn remains a popular choice for enthusiasts and those who require a rugged and practical vehicle. The Bighorn laid the groundwork for Isuzu’s continued presence in the SUV market, and its robust design continues to appeal to drivers today.