Freightliner Cascadia Losing Power When Accelerating – What's Wrong?

The Freightliner Cascadia is one of North America's most popular heavy-duty semi-trailers. It is made by Freightliner and was introduced in 2007. Its design emphasizes a lot on fuel efficiency and performance, and this has seen the popularity of the truck grow exponentially. But is the Cascadia all that powerful and reliable?

Our article today investigates what causes the Freightliner Cascadia to lose power when accelerating. We look into what could be wrong and the possible causes of this problem. But to get the best understanding of the problem at hand, we will start by giving an overview of the semi-trailer.

Freightliner Cascadia overview

The Freightliner Cascadia is a reliable heavy-duty semi-trailer that has been in the market for almost two decades. It has undergone quite some changes over the years, but none to make the 2023 Cascadia drastically look different from the 2008 version. It's a favorite pick for professional haulers and long-distance operators because of the powerful engine under the hood and the unrivaled comfort in the cabin.

Over the years, the Cascadia has been powered by a range of engines such as Detroit DD13, 15, and 16. You will also find Cummins ISX 15 EPA, X12, and then the X15 in the 2022 model. It is a class 8 rig and has a horsepower ranging between 370 to 600 hp. The torque can go up to 2050 lb-ft, making it ideal for heavy loads and capable in all roads and environments. The rig's presence has increased, which means owner-operators are finding it more reliable than the competition or, at the very least, just as competitive.

The loss of power of Cascadia when accelerating

The Freightliner Cascadia is powered by powerful engines from either Cummins or Detroit. However, when the rig sounds like it's losing power when accelerating, one can't help but wonder whether it's the engine. Some of the causes are quite technical, but others are easy to solve and even prevent. Let us look at the likely causes of this problem in your Cascadia. 

1) A clogged air filter

The air filter tends to be forgotten during scheduled servicing of the rig. Remember, the Cascadia is turbocharged, which means an unobstructed flow of clean, cool air is required for the turbo. During everyday driving of your rig, debris, and dirt accumulate on the air filter, which makes the filter gradually lose its oomph.

It is almost impossible to find an air filter completely blocked, but you will find one with nearly no passage for air. When accelerating or going up a hill, the semi-trailer will have trouble. The air filter could even collapse, denying the turbo air.

Solution

Whenever your rig goes for scheduled service, insist on checking the air filter. The good thing about the Cascadia air filter is that it is easily accessible, and replacing it yourself is pretty straightforward. If you are nowhere near a service station, you can blow the filter, allowing the turbo to breathe, and this will help you reach a place where you can buy a new filter. An air filter is pretty, and failure to regularly check and change it can cost you thousands of dollars down the road.

2) Charger air cooler and plumbing fault

If you feel like the semi-trailer lacks enough power to climb a hill or accelerate on level, the charger air cooler or air plumbing could be the problem. A faulty charger air cooler will leak air; rather than sucking in air, it will blow it. Have a friend sit on the driver's seat and floor the engine. When you run your hand on the charger, you will feel and hear air blowing from the charger.

There is another charger air plumbing on the opposite side of the cooler. It allows uninterrupted airflow into the turbo from a charger cooler. Any air leak from any of these plumbing will cause the rig to lose power, even on the flattest roads.

Solution

The solution to our problem is to tighten the clamps around the hoses. If the hoses are faulty, replace them immediately, as the semi-trailer pace can be reduced to a crawl, or turbo damage can happen. The other solution to the charger air cooler not sucking in enough air is to replace the air filter frequently or as recommended.

3) Faulty fuel filters

A malfunctioning fuel filter will cause your semi-trailer to lose power drastically. You may have carried out regular maintenance recently, and you feel like the rig is less powerful than before. The most probable cause is a faulty fuel filter or it has been installed incorrectly.

Solution

To find out whether the fuel filters are at fault, you will need to remove and check them. It is not hard to check fuel filters as they are easily accessible, and you only need a ratchet and a socket. The O-rings of the filter are likely broken or pinched, and this prevents free fuel flow hence the lack of power for the rig. If the fuel filters are clogged, then it is time to replace their fuel filters.

4) Faulty throttle positioning sensor (TPS)

This TPS is a simple cable that measures how far down the accelerator is depressed. A faulty TPS will cause your rig to lose power when accelerating but will idle just fine. In the case of the Cascadia, the computer fails to tell the engine to inject enough fuel as demanded, but at the same time, airflow is increased. Sometimes a faulty TPS will act erratic and cause your vehicle to accelerate normally, while other times loses power drastically.

Solution

You will need a diagnostic scanner to help you establish if the TPS is the source of the problem. You will likely get a P0121 code if the TPS is faulty. Replacing the TPS is easy. One cable end is screwed to the fuel pedal end, and the other is plugged into the computer. It is a plug-and-play solution, and you don't really need a mechanic.

5) Faulty injector

A faulty fuel injector is something, not very many people want to hear. The engine will misfire and lose power when accelerating, and in some cases, it will stall. Of course, there will be other symptoms to check out, such as fuel odor and the check engine light.

Solution

Confirm whether you have an injector problem by reading the codes the computer is throwing. Replacing an injector for Cascadia can be anything between 1,500 and 2,000 dollars, excluding labor. This is not something you want to do. Check the related sensors to ensure the problem is solved and it doesn't return.

6) Faulty EGR line

Some operators of Cascadia have had the EGR lines of their rigs replaced once they complained of loss of power when accelerating. A faulty EGR makes the semi-truck lose power and causes the general performance to deteriorate. Fuel consumption increases, as well as the emission of harmful gases.

Solution

The right diagnostic scanner should give you the proper codes to help you solve an EGR problem. When you take the rig to the dealership, you may find the EGR line being repaired or replaced, and sensors such as the outlet NOx and Delta P will also be replaced.

7) Faulty primer pump

The primer pump plays a critical function in ensuring the fuel flows uninterrupted. A faulty primer pump will likely cause the engine to misfire, hard start, and lose power when accelerating. The check engine light will also pop up.

Solution

Once you have tested the airflow, the air filter, and the fuel filters, and you still can't get the rig to go, check the primer pump. This pump is found on the left side of the Freightliner Cascadia next to the fuel filter. Unscrew the pump with your hand. Start pumping the pump, which at first will be lost. Pump until it is hard, and you can't move anymore. Fire the truck, and you will be on your way.

Is losing power when accelerating common for Cascadia trucks?

A Freightliner Cascadia is pretty solid and reliable. Generally, it is expected to run for 500,000 miles without developing any serious issues. With proper maintenance, the truck should serve you perfectly. However, once the half-a-million mark is passed, you are likely to experience issues just like you would with any other truck or car.

Regular maintenance and checking your truck frequently will go a long way in ensuring that you don't experience problems while on the road. As a Freightliner Cascadia driver or owner-operator, it will help you a lot along the way when you familiarize yourself with how the engine and other parts work. This way, whenever you find the semi-trailer losing power when accelerating, you will have an easy time solving the problem.

Conclusion

In this article, we have looked at why your Cascadia might be losing power when accelerating. Whether new or old, solving an acceleration issue in your Cascadia is easy. By following the above tips, you will likely have little to no downtime because of loss of power when accelerating with your Freightliner.