Let's Talk Fuel Systems Part 1
How Fuel Delivery Works
Fuel is securely stored in the fuel tank. When your engine is running, the fuel is pumped by the fuel pump through the fuel lines to the fuel injectors. On the way, it passes through the fuel filter, which traps dirt or other contaminants, preventing them from reaching the engine.
Once the fuel reaches the fuel injectors, the ecu and sensors determine the precise amount of fuel that must be squirted into the intake manifold. Inside the manifold, the fuel mixes with air in a precise 14:1 ratio monitored by other sensors. Once the two elements have thoroughly mixed, the mixture is drawn into the cylinders. Inside a cylinder, the mixture is compressed and then ignited by the spark plugs at a precise moment to produce combustion.
Keeping the Fuel System Clean
As time passes, the fuel filter can become blocked by contaminants, restricting fuel delivery and reducing engine performance and acceleration. Carbon and other substances can build up in the system and block the fuel lines or the injectors. We at Fflat Four have some ways of keeping it all running efficiently
Using the correct fuel
Super Unleaded (97/98 RON): Higher octane fuel, often used in high-performance cars that benefit from the increased power and efficiency.
High-Performance Fuels (99 RON): like Shell V-Power Unleaded, or tesco momentum which has a RON of 99.
Clean Injectors
As we saw above, the injectors spray fuel into the intake manifold in precise amounts. We can carefully clean all the injectors to remove any fuel residue or build-up and clear any blockages in the injectors.
Subaru top feed injectors shown below
Clean the Throttle Body
Fuel varnish can accumulate and jam the fuel throttle. This varnish is the gummy residue of decaying fuel. Many drivers don’t know this, but fuel degrades if it’s left in the gas tank. Once the throttle has been cleaned, it will control the airflow into the manifold again.
Clean the Valves
This step isn't simple but just as important as cleaning the throttle body, as the valves control fuel access into the injectors. Once they’ve been cleaned, the correct amount of fuel will pass through to the injectors. cheapest option for this is to add a fuel system cleaner when you fill
your fuel tank ..this would help clean your fuel lines and valves
Change the Fuel Filter
A fuel filter can also become clogged. This restricts fuel delivery and can lead to engine trouble definitely a service item and a cheap part to replace on a 2 yearly basis or 18k ..
1991-2005 impreza it's a simple job ..
from 2006 on the filters were put in the fuel tank and these tend to be overlooked ..
1992-2005 fuel
Filter shown below
Part 2 we can talk fuel Pumps
