Car Fuel Injectors
#7 Fuel Injection – Time for a Bath?
To have better fuel economy, a more predictable and efficient burn in the cylinder is needed and therefore clean fuel injectors that provide a more even fuel-air mix are needed. To illustrate this refer to the photos:
- The top picture shows the spray pattern of a dirty fuel injector
- The bottom picture shows the full flow spray pattern from a clean injector
How do fuel injectors become dirty?
Contrary to air filters and what would seem logical, fuel injectors become dirty mostly from the fuel itself and not from dirt or debris in the fuel (unless the car’s fuel filter has not been performing or has not been replaced regularly).
Petrol contains waxy compounds that can leave varnish deposits at the injector pintle when the fuel evaporates. This commonly occurs after the engine is turned off. The heat that is generated from the engine evaporates the residual fuel in the injector tips, leaving a deposit of varnish. These deposits in the nozzle build up and restrict fuel flow or disrupt the injector’s spray pattern (as seen above). On many late-model engines, the shape and direction of the spray pattern is critical for clean combustion and good performance. If the injector nozzle is dirty, the pattern may be distorted or deflected to one side, causing a lean spot in the combustion chamber that can cause misfire, or even pre-ignition or detonation and can cause car engine problems.
What tolerance is there for injectors? The simple answer is it does not very much of a restriction in an injector to lean out the fuel mixture. To put a measure on it, an 8% to 10% restriction in a single fuel injector can be enough to upset the air/fuel mixture and cause a misfire.
There are two main methods of cleaning fuel injectors. The fuel injectors can be cleaned on an inline basis (on car) or better still by having them removed and given and ultrasonic bath. If your injectors have performed close to or over 100,000 km without being thoroughly cleaned, your fuel economy will certainly improve once services and cleaned, translating into direct savings.
Call 13 20 42 for your ACE Mobile Mechanics should your fuel injectors are due for a clean and service.
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