Unit Injector (Pump Injector)
A unit injector combines the high-pressure pump and the injector in one unit for each cylinder.
What is Unit Injector (Pump Injector)?
It was used on many diesel engines before common rail became standard. A camshaft lobe drives each unit injector. It can create very high injection pressure. Some heavy vehicles still use unit injectors. Workshops measure injector performance on test benches.
How it works
The camshaft pushes a plunger in the unit, building pressure that opens the nozzle when a solenoid valve closes.
Why it matters for your car
Worn camshaft lobes or rocker arms affect injection. Replacement may require coding and correct adjustment.
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