Fuel Injection System - Diesel: Operation: Injectors
The injection spray nozzles spray fuel into a combustion prechamber as each compression stroke occurs. Nozzles can be disassembled, cleaned and adjusted to correct improper spray patterns.
Injector opening pressure can be adjusted with shims 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 fuel to pass into the prechamber.