Exhaust systems have undergone quite a few changes over the years to help make them cleaner and reduce the risk of carbon buildup.
Diesel Particulate Filters (DPFs), for example, have been added to exhaust systems in recent years. They are designed to eliminate carbon, soot, and the diesel smell as well as clean the exhaust.
This helps the VGT turbo, which is downstream from the DPF and relies on a strong airflow to keep the turbine moving.
As with the other components in your EGR system, regular maintenance keeps your DPF operating at its best. This helps ensure your VGT and engine as whole are running great.
This article will go through what DPFs are as well as what to look for if they fail.
The Arrival of DPFs
It wasn’t all smooth sailing when DPFs were first introduced. They weren’t always perfect when you took them out of the box, as is the case with most new technology, and this resulted in a lot of failed, cracked or broken DPFs.
This created a number of problems because one of two situations generally arose:
- The filters were out of warranty and the manufacturers wouldn’t stand behind them.
- They weren’t used or maintained properly and didn’t qualify for a warranty.
This meant that not only were they expensive, but they gained a reputation for being unreliable. Operators had two options when a DPF failed: replace it for $3,000 to $7,000, or put on a pipe and get rid of it altogether.
This led to a lot of eliminations. DPFs just weren’t as well made in the beginning as they are now.
Is My DPF Failing?
A failing DPF causes a few noticeable symptoms. If you’re DPF is failing you might have some of the following four symptoms:
- Cracks in the DPF filter that cause black smoke from the tailpipes
- VGT doesn’t spool correctly
- DPF Differential Pressure Sensor Alert on the dash, alerting you to a plugged DPF
- Soot in the tailpipe, indicating an internally damaged DPF that allows soot to pass through the filter
What a Failed DPF Can Tell You About Your Engine?
A problem with your DPF filter is often caused by another failed component upstream in your engine. These failures can cause excess carbon and soot.
Timing issues and injectors that aren’t firing properly are both common problems which can lead to a plugged DPF.
Worn Injectors
Worn injectors that aren’t spraying the fuel at the right pressure don’t have proper atomization. This means the fuel-to-air ratio isn’t correct.
If the ratio is off, it doesn’t burn as clean as it should which causes more particulate matter. This plugs the filter.
Once the process begins it has a cascading effect, where the plug builds faster and faster as the problem is multiplied.
Bore Polishing
Bore polishing can also lead to DPF failures. If you don’t have APR rings installed in your engine, carbon can build on the top and side of the piston.
This leads to incorrect temperatures and poor burning.
DPF Filter Light
If your DPF filter light shows up on the dash, you might be facing a regeneration that takes your engine out of commission, but ignoring the problem could lead to total filter failure.
This has led OEMs to void warranties because of improper filter maintenance, leading to a hefty replacement bill.
VGT Turbos
Your VGT can also be damaged by a failing DPF.
The exhaust side turbine wheel is downstream from the DPF. It’s driven by exhaust gasses, and if the filter is plugged, thus restricting airflow, the turbine wheel can’t spool properly.
Your compressor wheel is affected by the slow turbine speed as it can’t bring in enough cold air for combustion. Your VGT can no longer perform optimally.
Keeping Your DPF Operating Properly
Regular maintenance is key to preventing DPF filter problems. Cleaning the DPF helps prevent clogs and buildup.
For a proper cleaning, the filter must be removed from the vehicle. It then goes through a special cleaning process. A regen alone won’t do the job.
Clean the DPF every six months for optimal performance.
HHP Can Help!
If you’re having trouble with your DPF filter, give us a call!
We can answer your questions on your DPF filter or other problems with your diesel engine. Our ASE Certified Staff can help you diagnose your problem and make sure you’re getting the parts you need to get the job done.
From diagnosis through delivery, we’re Highway & Heavy Parts!
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