Direct injection engines or GDI (Gas Direct Injection) increase power and efficiency, as well as enhance its fuel economy.
On the down side, carbon in the intake port and on the intake valves are not being rinsed off as it would be with normal port injection, reducing its performance and efficiency over time. If the valves get too much of a build-up on them, the car could even develop a misfire and lumpy idle and throw a cylinder misfire error code.
Cleaning the intakes valves is a very crucial maintenance element on direct injection engines. In fact, some manufacturers are including the cleaning as a regular maintenance service interval.
The carbon build-up is a by-product of the combustion process and being worsened by the addition of EGR valves and un-baffled crank case breathers.
The build-up can be decreased by the fitment of a Baffled Oil Catch Can/Tank and the Blanking/Removal of EGR Valves.
How often should you do Carbon Cleaning?
At least every 60 000 km, In fact, some manufacturers are including the cleaning as a regular maintenance service interval. Often the performance decline is so gradual that drivers do not realize that their car is experiencing a power loss.
What is the process?
We use walnut blasting to clean the intake valves. Walnut blasting is the most effective and environmentally friendly way to remove the carbon build-up. There are a few other ways to accomplish the same/similar results, but are not as effective.
The intake manifold is removed and Walnut shells are blasted into the dirty areas with compressed air, blasting away the carbon build-up. This is done on each cylinder while that cylinder valves are closed, to prevent the digest of the Material and dirt. Walnut shells are used because they are strong enough to remove the carbon without damaging the metal and rubber components of the engine.