You’re sitting in the cabin of your parked diesel truck while its engine is running. However, the vehicle shakes while it’s idle. Why is it vibrating? Also, what can you do to fix this problem? We researched and consulted with experts regarding this concern, and here’s what we found.
Different suspects may cause a diesel truck’s engine to shake while idling. These possible culprits may range from dirty valves to obstructed fuel intake systems. So, troubleshoot your vehicle first to find the source of the issue. Then, use the appropriate technique based on your findings to fix the problem at its source.
Continue reading as we discuss these possible reasons why your diesel truck shakes while idling in greater detail. We’ll also tackle some solutions that might help you in solving this problem.
What Causes Rough Idling On A Diesel Truck?
Take note that troubleshooting your diesel truck can help you search for the source of the shaking while the vehicle is idle. Also, this vibration can come from different sources, such as:
Dirty Idle Air Control (IAC) Valve
The IAC valve functions by controlling the air going in and out of the engine. But carbon deposits and other debris may build within this component, causing an improper air distribution. The engine may jog, rattle, or vibrate each time an incorrect amount of air passes through the IAC valve.
Aside from improper air distribution within an idle diesel truck engine, debris buildup in the IAC valve can also reduce the vehicle’s revolutions per minute (RPM). The vibrations may also become apparent if you’re driving the truck at low speeds.
Faulty Or Unclean Spark Plugs
Spark plugs are responsible for igniting the air and fuel in an engine, causing an explosion at the right level. This instance allows the engine to produce power to make the vehicle run.
Over time, the spark plugs in an engine, particularly in your diesel truck, can become dirty or worn. If so, these components may fail at providing the appropriate force to ignite the fuel, causing vibrations.
Broken Or Loose Drive Belts
Take note that drive belts often come in three types:
- Serpentine: An old-style drive belt typically found between different assemblies.
- Timing: Typically connected to the crankshaft and camshaft to help them rotate.
- V-belt: Generally helps different systems, such as the AC and power steering, to work normally.
If these drive belts break or become loose, your diesel truck may encounter shakes and vibrations during different instances. These unwanted motions may occur while the vehicle is idling or when you’re driving on a highway.
Apart from the vibrations, broken or loose drive belts may also lead to other issues like:
- Engine misfires
- Engine stalls
- Power loss
- Complete engine shutdown
Worn Engine Mounts
As its name implies, an engine mount works by holding the engine in place. Generally, it secures the engine block with the help of multiple bolts and screws.
Although many truck diesel engine mounts have quality constructions, they might still encounter breaks or cracks. If so, the engine won’t be secure as it runs, leading to the shakes while idling. These vibrations may also appear at roughly any time while the engine is running.
Obstructed Fuel Injection System
The fuel injection system has different assemblies and components. These parts include the fuel tank, filter, cooler, heater, and supply pump.
Normally, this system should work properly as it injects fuel into the correct areas of your truck's engine. But a blockage may prevent the framework from functioning correctly. This clog might make the truck shake, especially while it’s idle.
How Do You Stop A Diesel Engine From Vibrating During Idle?
Remember to troubleshoot your truck’s diesel engine to find the source of the shakes while the vehicle is idling. Then, use the correct technique to eliminate the problem from its source.
In this section, you’ll find some possible solutions that you can use to help remove your diesel truck’s shaking concern:
Clean The IAC Valve
Take note that it can be difficult to access the IAC valve without removing the engine block from the hood. So this procedure can be fairly straightforward if you take out the diesel engine from your truck first.
With the engine out of your diesel truck, and you placed it on a clean and flat surface, continue this operation by following these steps:
What You’ll Need
- Automotive car cleaner
- Socket wrench
- Philips screwdriver
- Microfiber cloth
- Disconnect the connectors attaching the IAC valve to the engine block.
- Unscrew the bolts on the IAC valve.
- Swing the IAC valve to the side to expose the gunk and debris buildup.
- Remove the plate surrounding the area with the buildup.
- Unscrew the metal plate on the IAC valve.
- Spray the automotive car cleaner on the gunk collection, including the spots in the valve.
- Wipe off the cleaner’s residue with a clean microfiber cloth.
- Return the assemblies and parts you removed to the engine block.
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If you don’t have any other work to do with the engine block after returning the IAC valve, reinstall the engine to the truck. Then, ignite the diesel engine to check if the shaking persists while the vehicle is idle.
You can also watch the video below to see a visual guide highlighting the steps mentioned above:
Clean The Fuel Injection System
First, open the hood and find the location of your diesel truck’s fuel injector. If you have trouble locating this component, consult your vehicle’s owner’s manual. Otherwise, ask your truck manufacturer or dealer’s customer service representative for the information you need.
Once found, continue this process by following these steps:
What You’ll Need
- Car deposit cleaning kit
- Unscrew the cap on the car deposit cleaner.
- Pour the solution into the container.
- Attach the hose that should come with the cleaning kit to the fuel injector.
- Remove the fuse of the fuel pump relay.
- Connect the air supply hose from the engine to the cleaner’s container.
- Turn on the valve that releases the air pressure from the container.
- Start the truck, which should siphon the cleaner from its container to the fuel injector.
- Turn off the engine and the cleaning kit’s valve once you see air going through the hose.
- Remove the cleaning kit, and return the fuse to the fuel injection relay.
- Start the truck’s engine again to check if the vibrations persist.
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Watch this video to gain additional insight into this procedure:
Do Diesel Engines Vibrate?
Diesel engines, particularly in trucks, vibrate because of the internal combustion happening under the hood. Truck owners may also tweak their vehicles’ engines to reduce the intensity of the shakes. However, it can be a good idea to have a technician troubleshoot, check, and repair your truck’s underlying issues if you can’t find and/or solve the cause of the engine’s excessive shaking.
How Much Does It Cost To Fix A Diesel Truck Engine?
The expenses to repair a diesel truck engine often depends on the problem to solve. For instance, owners should prepare to spend about $180 for a coolant flush. On the other hand, an oil change often has prices that range from $70 to $200. However, repairing the engine’s induction system typically has costs that start at $500.
Generally, diesel trucks shake slightly as it idles. But excessive vibrations may appear because of underlying issues, such as a dirty IAC valve or a loose drive belt. You can fix these problems using DIY techniques. But don’t forget that reliable automotive technicians are available if you don’t have the knowledge, skill, or confidence to proceed and/or complete these jobs.
If you want to know the answers to other truck-related problems, check out these other great reads:
Water In Floorboard Of Truck – Why And What To Do?