Despite the emissions test scandal often referred to as "Dieselgate" or "Emissionsgate," that began in September 2015 and resulted in the worldwide recall of millions of diesel cars, the Volkswagen TDI (for Turbo Direct Injection), is still considered one of the most reliable diesel engines. Volkswagen designed the 1.9 TDI VP Engine (so designated by the VP, German "Verteilerpumpe," or "distributor pump" on the injection pump), with simple accessories resulting in exceptional durability. Volkswagen offered the first-generation engine in 75, 90, and 110 hp versions, all featuring a fuel delivery system using a Bosch rotary pump. A variable geometry turbine and a floating flywheel (on the newer models) contributed to the engine's performance and reliability.
Offered in several VAG (Volkswagen Audi Gruppe) models from 1991 to 2010, the 1.9 TDI gained notoriety for its low fuel consumption and excellent dynamics. Despite its reputation for reliability, the 1.9 TDI engine suffered from excessive vibration and rattling prevalent in the smaller, less expensive cars, that transmitted to the cabin at the steering wheel and pedals.
In the late 1990s, Volkswagen installed a pump-spray injection system that helped achieve higher injection pressures and improved fuel efficiency. However, the new system failed to reduce the engine vibrations. VAG manufacturers installed oil-filled rubber engine mounts to help reduce the shaking. The 1.9 TDI engines were exceptionally noisy, especially when installed in the base-model cars, and most often at low speeds. At higher speeds, the noise is less bothersome (most likely partially drowned out by normal road noise).