Injection Nozzles
The fuel injector has a liquid-controlled, throttling pintle nozzle, consisting of a nozzle holder, nozzle (with a nozzle needle), and a fuel return port. Like other diesel nozzles, it first injects a small amount of fuel, which vaporizes and ignites. As the needle continues to lift off its seat, the rest of the fuel is injected and combustion continues. See Fig 1 .
All models have an instrumented injector in the 5th cylinder. This injector has an electric coil and 2 outlet wires. Each time the nozzle needle moves, an electric signal is sent to the tripminder computer. The tripminder computer, located under the package tray of instrument panel, calculates fuel economy. See Fig 2 . These injectors are slightly longer than normal injectors, so the injection line going to the instrumented injector is slightly shorter than the others.
California vehicles are equipped with an extra instrumented injector installed in the 4th cylinder. Information is sent to the trunk-mounted computer to determine fuel flow and timing conditions. The computer can alter pump timing to control emissions.