Problems After DPF Removal

The Diesel Particulate Filter (DPF) is a critical component in a diesel vehicle’s exhaust system. So, if you are thinking of removing it, you need to be aware of the problems after DPF removal. Generally, it acts like a net, trapping harmful diesel particulate matter from the exhaust gasses produced by the diesel engine. This ensures that these particulates don’t get into our environment, reducing emissions from the vehicle.

Think of the DPF as a sort of honeycomb, similar to the Catalytic Converter (CAT) found in petrol engines. As exhaust gasses flow through it, the DPF captures and breaks down the diesel particulate matter. Typically, it can eliminate between 80% to 100% of these harmful particulates.

Removing a diesel particulate filter, or DPF can seem like a good idea at first. Not only does it get rid of a costly problem, but it also unblocks your car’s exhaust system. This blockage creates back pressure, and once it’s removed, your car has more power and runs better.

But taking out a DPF isn’t just about physically removing it. You also need to change the vehicle’s computer system. You have to delete the part of the computer that deals with the DPF. This is like making the car forget that it ever had a DPF.

If done right, and the DPF program section is mapped correctly out from inside the vehicle computer, your car should run smoothly without a DPF. It should be more reliable, more powerful, and get better miles per gallon. But the real issues aren’t just about how your car runs. It is also about the legal problems and risks. These could end up costing you more than if you just replaced the DPF.

This might all sound great, but there’s a big problem. You could be taking a serious risk that could potentially lead to criminal charges. While this isn’t very likely, it’s something you need to think about.

Problems After DPF Removal

1. DPF Warning Light Turns On

Sometimes the DPF light may come on and go off intermittently. While this does indicate a partial blockage, it also signifies that a regeneration process is required. Many people are unfamiliar with the DPF system and its regeneration process, especially those who have bought second-hand vehicles. Unfortunately, this lack of knowledge can lead to a disregard for the warning light, which could escalate the problem.

If the warning light is ignored, the DPF light may eventually remain on permanently. In severe cases, it can trigger the engine management light and even a blinking coil light. This usually results in a loss of power, and the vehicle will enter “limp home mode,” a safety feature designed to protect the engine. At this stage, a costly repair is inevitable.

2. Expensive DPF Replacement and ECU Reprogramming

Replacement of the DPF unit and reprogramming of the Engine Management ECU may be required, which could cost between $4,000 and $10,000 plus labour charges. Now, that’s part of the problems after DPF removal in terms of a hole in your pocket.

These costs vary based on the vehicle’s make and model, and location. Certain dealers in locations like Wollongong NSW have been known to charge an extra $3,000 per job. Furthermore, resetting the ECU light will add a further cost of $150 to $250.

3. Increased Mileage

Some users report an increase in miles per gallon (mpg) after the DPF removal. However, this is not a universal experience, with some people not noticing any significant change. The variation could be due to different driving styles or loads.

4. Teething Problems with Gen 2 Deletes

Some people have reported problems after DPF removal due to the second generation of delete kits, which seem to have some initial issues. Some users do not face these problems at all.

5. Potential for Code Clearing

Running certain tuning devices could clear any codes triggered by unplugging the EGR or removing the DPF.

6. Potential Legal Consequences

Removing a DPF is considered illegal in many parts of Europe, including the UK. Non-compliance with these regulations can result in the owner’s prosecution and fines. But you could do these if you get caught with a deleted DPF.

7. Implications for Vehicle Testing

The MOT checks are not easily bypassed due to visual and more intrusive checks that could detect DPF removal. Moreover, since February 2014, when an MOT tester inspects a diesel vehicle’s exhaust system, they have to check if there’s a DPF. Diesel particulate filters are now considered in maintaining acceptable levels of air quality.

8. Insurance Coverage Issues

DPF removal is a major, unlawful vehicle modification that should be reported to the insurer. Since it’s an illegal act, it makes the vehicle uninsurable. This could have serious consequences in the event of an accident, including potential prosecution, criminal conviction, and financial liabilities.

9. Tax Implications

Removing a DPF increases vehicle emissions, which may alter the vehicle’s VFD band and affect the amount of annual road tax due. This could result in the DVLA prosecuting the owner for fraud or demanding back tax payments which cause problems after DPF removal.

How Does DPF Additive Work?

Diesel Particulate Filter (DPF) systems are commonly paired with an oxidising catalytic converter. This is usually located near the engine. The exhaust gases there are still hot enough to let passive regeneration happen. That’s a fancy way of saying it can clean itself.

But sometimes, there’s not enough room near the engine. In that case, some car makers use a different kind of DPF system. This one needs a special fuel additive to burn off the dirty bits at lower temperatures, allowing the DPF to be placed further from the engine.

The special additive is kept in a separate tank. It gets mixed with your fuel automatically when you fill up your car. You only need a tiny bit of this additive for the cleaning process to work. For example, 1 litre of DPF additive can work with around 2800 litres of fuel. This is enough to cover about 45,000 kms if your car uses 7.1 litres for every 100 kms. The car’s computer, or ECU, usually starts the cleaning process every 300 miles or so. This varies from car to car. The whole thing takes about 5-10 minutes. Most of the time, you won’t even notice it’s happening. When it’s done, you might see a little puff of white smoke from the exhaust, and that’s it.

Consider EGR Valve Unplugging

Some experts suggest simply unplugging the Exhaust Gas Recirculation (EGR) valve as an alternative to DPF removal. This can potentially increase mpg and is considered a less drastic measure than DPF removal. However, this could lead to a check engine light warning, and the engine might rattle a bit more with the EGR unplugged.

Cars with DPF Problems

Many vehicles are suffering from Diesel Particulate Filter (DPF) system failure. The DPF system is becoming increasingly common as it’s being installed on almost all new Diesel engines. Although this issue will become more prevalent in the future, we currently frequently deal with DPF problems in some vehicles. Here’s a tabulated list of the most common cars that we see suffering from DPF problems every week:

How Much Does it Cost to Fix DPF?

If you don’t pay attention to the warning lights and let the diesel particles keep building up, the DPF might completely fail. If this happens, you’ll need a new DPF, which can cost anywhere from $4,000 to $10,000. On top of that, you’ll have to reset the car’s computer. This usually costs between $150 and $250.

Once these repairs have been completed, it’s essential to remain vigilant for the DPF light on the dashboard. Neglecting it again could lead to repeated damage and potential voiding of the warranty associated with the new DPF unit, which could double the cost. Therefore, understanding the DPF system, recognizing the signs of problems, and taking prompt action is crucial to preventing costly repairs and maintaining a functional and efficient vehicle.