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Direct Injection Carbon Build Up: Symptoms and Preventative Measures

Direct fuel injection in the engine is more prevalent these days because it enhances the fuel economy. However, it’s not an ideal method as carbon is deposited on the piston, intake valves, and other surfaces in the combustion chamber. To understand how direct injection carbon build up and prevent, let’s consider both the aspects differently.

Direct Injection Carbon Build Up – Why It Happens?

Without any fuss, let’s straightway jump to the reasons behind the problem.

1. Unable to Clean Valve and Port

The main cause of carbon buildup on valves is that the added detergents and fuel don’t come in direct contact with the intake valves. It mainly happens because the fuel is injected directly into cylinders instead of a place behind the valve. As a result, the fuel and detergent are unable to clean the port and valve.

2. High Combustion Pressure

The problem gets worse during higher combustion pressure and leaner mixtures.

Actually, during direct fuel injection more energy is produced than the fuel injection from the port. So, when the sub-optimal flame front is generated, the unburned fuel increases inside the combustion chamber.

Additionally, during valve opening for intake stroke, these byproducts are exposed to the valve, thus forming the carbon deposit.

How to prevent direct injection carbon build up
Symptoms of direct injection carbon build up. Source: WapCar

Note: Even the air passing through the valve is not hot enough to burn these byproducts.

3. Another Cause

When intake valve goes into the combustion chamber for a small period, the byproducts of the combustion process meets the valve, which sticks to the neck of this part.

         SEE MORE:

How to Prevent Direct Injection Carbon Build Up?

With oodles of ways to prevent direct injection carbon build up, there are indeed three best possible ways you can try:

1. Regular Maintenance

One of the ideal ways to prevent carbon build up is periodic maintenance. While following the essential maintenance tips, the full synthetic oil is to be changed after every 5,000 miles. This allows intake valves to perform efficiently.

2. Spark Plug Replacement

To reduce the deposition of unburned fuel in the chambers and thus sticking of it to the valves, demands the spark plug replacement.

Tip: Accurate time for replacing plugs depend on the recommended mileage by the factories.

3. Clean Up of Fuel Injectors

Cleaning is essential for correct spray of fuel into the chamber. Therefore, its service after every 30,000 miles is what can save you from huge expenditure, later.

Last but not the least, a new software update in ECM of the car can help in reducing carbon buildup on valves by adjusting the time of spark plug and valve.

Effects of direct injection carbon build up
How to stop direct injection carbon build up. Source: Pinterest 

To wrap up, these tips will surely help in preventing the direct injection carbon build up. For more information on the preventative measures, you can also consult the reputable car repair and maintenance shop.

Check out the video to understand deeply about why direct injections have problems with carbon:

Hopefully you will understand more about carbon build up on Direct Injection Engine and solutions to clean them off the valves through this article. If you have any question about this topic, feel free to leave us a comment, our auto experts will answer it for you.

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  1. Paul says

    Hello, I’m having trouble with my proton jumbuck 2005 with 57000 miles.
    It starts when cold on the turn of the key, it drives faultlessly for around 30/40 mins,
    then it like I’ve run out of fuel, it splutters along and then just stops. If I try and start the car straight away it won’t have it. But after around 5/10 mins it starts again and it will drive for around one mile before stopping again.
    Can anyone help me, there mustbe someone who knows what’s going on.
    I’ve had it in the garage to try and resolve the problem but they just say it’s a matter of replacing different sensors that would cost a fortune.
    I would appreciate any help that anyone could give.
    Thanks for reading this, I’ll keep my fingers crossed..
    Regards Paul.

    1. Billy says

      Hi Paul, it seems that your car shuts off while driving. Hope this article could help:

  2. Maritza says


    I have a opel corsa lite. it drives fine, then all all of sudden the car will starts to jurk, then when I brake to stop the revs will drop and the car stalls, It does not happen al the time, I will drive and then all of a sudden it will do that. then after the car will drive perfect. I had the car at 4 garages and the told me there is nothing wrong with my car. The last garage change the spark plugs, the car was driving fine for 3 weeks and now back to the same problem.

    1. PAUL DO says

      This sounds like the fuel pump is about to die..

  3. Jose says

    Hi There

    I have a Toyota Auris 2008 2.0 L engine, the car runs ok but it shows a lot of black smoke at start point and sometimes in the morning the car doesn’t start easily, my garage cleaned the EGR valve but they suggest to sell the car as cost to repair it can be too expensive, but the engine and car feels very powerful and still running ok apart from the smoke and the early morning starting problem, I wonder if someone can help here to decided what to do, at the moment the EGR valve it is being replace by a private Mechanic, I wonder if I will have to strip the engine to clean up all the carbon that produce the clog?
    Thanks in advance

  4. Tammy Rice says

    Hey Tsukasa! thanks for sharing your worthy tips with us. It will help me a lot.

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