Paccar MX13 - Loss of Power. Common Reasons and Fixes

The Paccar MX13 is a diesel engine in Paccar's MX lineup of engines recognized for its efficiency, durability, and low carbon footprint. A number of trucks use the Paccar MX13 engines. You will find Paccar MX13 on trucks from Kenworth, DAF, and Peterbilt. The 12.9-liter Paccar MX13 engine is fairly lightweight, which gives room for hauling more load than many 15-liter engines. It has a peak horsepower of 500, a peak torque of 1850 pound-foot torque, and an engine speed of 2200 revolutions per minute.

Despite its advantages, the Paccar MX13 can suffer from loss of power. Below we explore some common reasons for power loss in the Paccar MX13 engine and how you can fix them. Finally, we share some tips for preventing power loss in a Paccar MX13.

Common Reasons and Fixes for Loss of Power in The Paccar MX13 Engine

Loss of power in an engine is when it functions at a lower speed than expected while you are accelerating. Understanding what may cause this issue is crucial for fixing it. Below are common reasons for a Paccar MX13 engine to suffer loss of power and how you can fix them.

1) Clogged or Blocked Fuel Filter

The fuel filter protects the engine fuel system components from debris and dirt that could clog it. Yet, the fuel filter, with time, can become clogged. Depending on the particular MX13 you have, there may be one or two fuel filters.

Once the fuel filter becomes too dirty, it causes problems. A clogged fuel filter can cause several problems in the Paccar MX13 engine, including rough idling and stalling, stuttering, jerking, and a loss of power.

A dirty fuel filter will reduce the rate and volume of fuel discharge to the cylinder. This will cause inefficient combustion and inefficient power generation, resulting in a loss of power. With the aid of an onboard diagnostic, you should be able to detect anything that can reduce fuel pressure, including a clogged fuel filter. The trouble code for low fuel pressure in the Paccar MX13 is P0094.

Should the loss of power in your Paccar MX13 engine be the result of a clogged fuel filter, you will need to change it. Changing the fuel filter in a Paccar MX13 engine may be too intricate or complex for non-technical people. The process will involve cleaning the area around the fuel filter cap before removing it so dust does not enter the fuel system. Also, you have to remove the fuel filter cap until the O-rings are visible.

If you have two filters like in the 2021 Paccar MX13, there is a short period between when you can remove the first fuel filter cap and the second, to prevent air lock. Besides, because of fuel system contamination, you cannot loosen the fuel filter cap beyond a certain level. Some other things to take care of include cleaning the drain plug valves' surroundings, draining water and fuel, changing the filter, lubricating the rings and seal, and priming the system by hand.

As you can see, fixing a bad fuel filter yourself is a bit much. So, we recommend using the help of qualified mechanics to replace your Paccar MX13s fuel filter.

2) Injector Problems

The 12.9L Paccar MX13 engine uses a common rail with two high-pressure pumps on the engine block for fuel injection and induction. With this system, fuel gets to all the cylinders from a single (common) rail at a specific but significantly high pressure. The injection pressure on the Paccar MX13 can reach a maximum of 2500 bar. The common rail system in the Paccar MX13 can be advantageous in terms of fuel vaporization, efficiency, reduced emission, and smoothness.

The source of injection issues could come from any of the components in the Paccar MX13s common rail system, including the high-pressure pumps, the rail, injectors, or even the Engine Control Unit (ECU). A small shift from optimal fuel atomization in the Paccar MX13 due to any of these components may lead to a loss of power.

Besides the loss of power, some other symptoms of a failing injector include engine misfires, rough idling, and visible exhaust smoke. You can confirm if you have an injector-related issue with a diagnostic device. A P228D refers to an incorrect engine rail pressure control on a 2013 Paccar MX13.

Fixing loss of power caused by a failing injector in the Paccar MX13 may involve any of the components in its common rail system. Fix all error codes one after the other. Afterward, you should conduct fuel flow rate and pressure tests to ensure the injection system is back to its optimal level. Once again, these procedures will be above most people, so see a professional if you cannot proceed.

3) Clogged Exhaust

A clogged exhaust may not seem an obvious cause of power loss in a Paccar MX13 engine. Yet, it is a likely cause. The exhaust pipe through the catalytic converter and Diesel Particulate Filter (DPF) reduces the number of harmful pollutants the engine will emit. With time the soot can build up and clog the exhaust system, preventing seamless carbon emission.

This situation can cause a buildup of exhaust back pressure. Excessive back pressure beyond the maximum accepted levels will cause issues with exhaust leaving the cylinders. Resultantly, this may affect how the Paccar MX13 breathes, potentially leading to a loss of power. Furthermore, the engine may not even start because of the absence of an escape for the excess exhaust back pressure.

Signs a clogged exhaust system is causing the Paccar MX13's loss of power include poor fuel efficiency, difficulty starting, bad smell and sounds from the exhaust, and turbocharger damage.

Fixing a clogged DPF will involve burning off the soot clogging it. The soot is usually burned off as you drive in a process known as passive regeneration. Nevertheless, you may need active or forced regeneration. Some methods you can use to clean the exhaust of your truck include:

§  DPF cleaner

§  Pressure Wash

§  Pressure Gun/Compressed Air

If none of this works for you or you find performing them beyond your ability, get the help of a technician to solve the problem.

4) Compression issues

The loss of power in the Paccar MX13 engine could be from the compression system. Compression is necessary for starting combustion in the Paccar MX13. Diesel engines like the Paccar MX13 do not ignite in a spontaneous manner. Instead, the compression of air in the combustion chamber creates very high temperatures.

Essentially, diesel engines like the Paccar MX13 need high compression for combustion. Thus, a higher compression ratio will lead to more power, and a decline will lead to poor combustion. Poor combustion will cause a decrease or loss of engine power. The high-pressure pump controls the compression ratio. The correct compression ratio for the Paccar MX13 is 18.5 to 1.

Several things can cause compression issues in the Paccar MX13, including an issue with the piston rings, cylinder walls, head gasket, or damaged valves. You need to conduct a diagnosis to discover the source of the compression problem. Repair or replace the affected component.

5) Turbocharger Problem

Turbochargers help to manage the amount of air pressure the turbine supplies to the engine. Additionally, modern diesel engines like the Paccar MX13 use turbochargers to help improve fuel economy and reduce emissions. The Paccar MX13 uses a Variable Geometry Turbocharger (VTG). A VTG uses adaptable vanes to regulate the flow of exhaust through the turbine.

If the regulator or solenoid valve for the turbine has a problem, it could disrupt the supply of air to the combustion chamber and result in a loss of engine power in the Paccar MX13.

To fix the issue, repair the regulator or solenoid components to ensure adequate flow of air into the combustion chamber.

6) Other Possible Causes of Power Loss in a Paccar MX13

Some other things that could lead to a loss of power in a Paccar MX13 engine outside of those we mentioned above include:

• Dirty or Clogged Air Filter
• Faulty Spark Plugs
• Intake system leaks
• Valve train wear
• Faulty camshaft

How To Prevent Paccar MX13 from Losing Power

• Service and maintain the Paccar MX13 engine regularly. Regular inspection and tune-ups will help identify and diagnose problems that could lead to loss of power before it becomes a major issue.
• Clean air filters and fuel filters frequently. After a certain level of use, replace them in line with Paccar's recommendations.
• Use high-quality fuel and oil for the Paccar MX13 engine. High-quality diesel fuel will have fewer contaminants that can clog the fuel system. So also make sure you use Paccar's recommended oil type for your Paccar MX13 to ensure proper lubrication and engine performance.
• Inspect the compression ratio frequently to see if it is at the optimal level.

Conclusion

The Paccar MX13 is a solid diesel engine for trucks and other vehicles that excels in terms of carbon emissions, fuel efficiency, and weight. Yet several issues could cause it to experience a loss of power. This write-up identified and explained some of the common reasons for a loss of power in the Paccar MX13, including clogged fuel filters, clogged exhaust, injection issues, compression problems, and turbocharger faults. We also touch on how you can fix these issues.

Some ways you can prevent Paccar MX13 power loss include regular servicing and tune-ups, cleaning the air and fuel filters, using high-quality fuel and oil, and monitoring the compression ratio. Doing all these things are helpful ways to prevent loss of power in the Paccar MX13.