Fuel Injection System - Diesel: Operation: Injectors
The injection nozzles spray fuel into a prechamber as each compression stroke occurs. Nozzles can be disassembled, cleaned and adjusted to correct improper spray patterns.
Injector opening pressure is adjusted with a shim on top of the needle valve return spring. See Fig 1 . The injector receives a high pressure pulse of fuel which forces open the needle valve allowing the fuel to pass into the prechamber.