International Truck Shuts Off While Driving – What's Wrong?

The International Truck brand, made by Navistar Inc of USA since 1909, consists of trucks of all sizes ranging from small trucks to full-sized tractors capable of pulling massive trailers.

They include commercial vehicles, roll trucks, delivery trucks, towing vehicles, and refrigerated trucks. Nowadays, the International Truck is powered by any of the International engine series such as the International S13 Integrated Powertrain, the MaxxPro Star, the International A26, the Cummins B6, and the Electrification among others.

The engines come in different series which include

• LT series
• RH Series
• HX Series
• HV Series
• MV Series

The International Truck takes about 13% of the truck market share in the USA. In this article, we shall discuss what causes the International Truck engine to suddenly shut down while it is driving on the road.

Electrical Issues

One of the most common problems affecting the International Truck is related to electrical failures and wiring issues. The modern International Truck, like most other trucks, has a lot of electrical-related operations in its daily running.

Engine combustion requires electric power to function. Cab controls, emissions, and fuel control systems are all electrically and electronically controlled. As such, any electrical issue will affect these systems which may lead to an engine shutdown. Some of these electrical issues include:

Battery, Alternator, and Motor Failures

1) Battery

The battery provides the initial power required by the Truck's electrical system. This electrical system powers the starter, the alternator, and the spark required to ignite the air-fuel mixture in the combustion chamber to kick-start the engine.

Battery issues could arise from 

• Dead or worn battery
• Loose terminals
• Corroded terminals or connections, or,
• Faulty alternator.

When the International Truck battery fails to provide the electrical power required by the engine, there will be no combustion process and the engine will not start. 

2) Alternator

The alternator converts mechanical energy into electrical power that is then channeled to the Truck's electrical systems. The alternator provides a steady flow of electric power for all the electrical components of the International Truck, including 

• The engine
• Lighting,
• The ECU,
• Cabin electrical devices,
• Steering, and
• The GPS

The alternator also charges the battery to ensure it has ready stored power for the engine start-up. All these components require a steady flow of electric power which the alternator provides. The battery cannot provide this power as it gets drained very quickly.

The alternator is rotated by a belt connected to the crankshaft. The belt rotates the alternator rotor which spins inside the stator and creates an alternating electric current through electromagnetism.

Relating to the topic of the day, the alternator provides a continuous electric charge to the motor which fires the spark plugs to ignite the combustion process. Signs of an impending electrical failure include

• Dimming or flickering lights
• Whining or growling alternator
• A hot alternator
• Dead battery
• Burning wires smell
• Battery warning light

Thus, a failure by the alternator to provide power to the motor will mean no combustion. This will automatically stall the engine and your International Truck will glide to a halt on the highway.

3) Faulty Regulators or Rectifiers

The alternator produces an AC while vehicles, International Trucks included use DC currents. The rectifier converts the alternator AC to DC while the regulator controls the amount of electrical current sent to each component. If these two devices are faulty, they will affect the current distribution and this can easily shut off the engine on the highway.

The current International Trucks have had issues with the electrical wiring, especially the power harness from the battery to the engine, the sub harnesses, the grounding wires, and the firewall connectors. These wiring issues affect the flow of electric power to the critical components such as the engine combustion, the ECU, and grounding. With such critical devices having powering issues, the engine is prone to sudden shutdowns without warning.

Thus, all matters relating to the electrical system of the International Truck can cause the truck to shut off on the road. It can be due to a lack of enough power to ignite combustion, or the ECU can detect electrical issues and send error codes or simply shut down the engine to avoid damage.

Fuel System Issues

1) Injector Pump Failure

The injector pump is a critical component of the International Truck engine. The injector pump delivers the right quantity of diesel at the right time and at the right pressure to the combustion chamber. The injector pump in the International Truck engine does the following:

• Providing diesel to the engine injectors
• Adjusting the amount of diesel available for combustion
• Adjusting the diesel injection timing
• Atomizing and pressurizing the diesel

This ensures a reliable and continuous power output from the engine to drive the truck.

The injector can have a host of issues such as electrical failure, low-pressure output, worn valves and seals, or fuel leakages that compromise its functionality. As such, should this pump fail, there will be little or no diesel delivered to the engine. Combustion will not take place and the engine will have no power to move on, hence it will simply shut down and stop.

Apart from fuel injection failure, other issues such as clogging of injector nozzles, clogged fuel filters, contaminated diesel, and fuel low pressure may cause the engine to stall. These problems compromise the combustion process as they reduce the amount of fuel reaching the combustion chamber, or the fuel availed for combustion is laden with impurities and, hence cannot ignite properly.

Engine Failure

Engine failure can be caused by a host of issues that result in the engine shutting off suddenly as you drive along. A failed engine is a culmination of a series of problems that have developed over time but have largely been ignored. These problems include:

1) Clogged Filters

Air and fuel filters must be regularly changed to ensure the engine operates optimally. When the air filter becomes clogged by dirt and debris, it will limit the amount of air delivered to the engine. As such, the engine combustion, the pistons, valves, and the turbo systems will be affected. 

Equally, a clogged fuel filter will limit the amount of fuel delivered to the engine. These problems will choke the engine for lack of air or fuel, leading to an engine stall in the middle of the road. 

2) Faulty Wrist Pin

The Navistar Company has had issues relating to the wrist pin in several of their International Truck engines. It had been discovered that these wrist pins were weak and prone to cracking. A cracked wrist pin would result in a connecting rod failure which instantly stalls the engine. Though it does not affect all trucks, it is a weak link in their engines and can easily lead to engine failures.  

(The Company had to recall thousands of trucks between 2019 and 20221 to rectify the wrist pin issue. It also requires International Truck operators to fix detection software systems to monitor the wrist pin and the connecting rods).

3) Malfunctioning Exhaust System

International Truck diesel engine is manufactured to comply with the strict EPA emissions standards in the USA. The EGR system has had issues resulting in a proportion of the exhaust gases flowing back to the engine. The engine manifold, exhaust valves, and other related components become covered in soot. This is catastrophic as it leads to engine failure.

ECU-Related Issues

The ECU controls all engine functions. The ECU also monitors all engine and other components' functions for errors and reports them on the dashboard. The ECU is powered by a direct power harness from the battery. A loss of power (or underpowering) to the ECU may result in erroneous error messages that the ECU is unable to comprehend. The ECU may report many inconsistent errors which in most cases are wrong.

One of the most common such errors in the International Truck is the loss of the Truck's speed sensor signal. This loss forces the ECU to shut down the fuel injection process, ultimately leading to an engine shutdown. Other faulty errors may force the ECU to shut down the engine to ´prevent engine damage' which does not exist. 

Faulty Fuel Pressure Regulator

The fuel pressure regulator (FPR) is in the fuel filter housing on the return side of the filter. Its work is to control and maintain the required fuel pressure in the fuel system by controlling the fuel flowing back into the tank. It is a simple spring that holds a check ball that moves to regulate the flow.

The regulator maintains a consistent fuel pressure for the injectors depending on the combustion requirements. A failed FPR causes a lean air-fuel mixture that does not correspond with the fuel mixture requirement. If the pressure is too high, the engine will misfire and produce excessive emissions due to too much fuel in the cylinders. When the pressure is too low, the engine will not produce enough power, forcing the truck to run rough and stall.