Duramax engines are renowned for their power, reliability, and fuel efficiency. But now the problem is that why is my Duramax getting bad fuel mileage? The average fuel mileage for different models of Duramax is 20 mpg on the highways and 14 mpg in cities, so if you are getting less than that, it’s time to take some action.
In this article, we will explore some of the most common reasons why your Duramax might not be delivering the fuel efficiency you expect and their solutions to get better fuel mileage in Duramax. Whether you use your truck for work or play, understanding what could be causing the problem can help you take corrective action and get back on track with better gas mileage.
Why is My Duramax Getting Bad Fuel Mileage – Causes and Solutions:
There are many causes due to which Duramax gets bad fuel. We see in detail these problems and solutions.
Incorrect Tire Pressure and Worn Tire Tread:
Most vehicle owners must be aware of the recommended tire pressure for their cars and ignore it entirely. This practice is not only harmful to the vehicle but also affects fuel consumption.
General Motors (GM) recommends 30 psi in front tires and 35 psi in rear tires for most vehicles. However, experts suggest keeping all four tires at 35 psi, which helps improve fuel efficiency and keep your car running smoothly. Low tire pressure increases friction between the wheels and the road, which requires more energy to move forward, resulting in higher fuel consumption.
Maintaining your truck’s tires can significantly affect its performance and fuel efficiency. One way to maximize both is by keeping 5 psi extra tire pressure than what GM recommends. This simple adjustment can result in significant savings in fuel costs while also improving the lifespan of your tires.
Lower Quality Diesel Oil:
There are 3 diesel types used in the GM Duramax engine.
- Petroleum diesel
- Synthetic diesel
There are two grades of diesel available in the market – grade 1 (1-D) and grade 2 (2-D) diesel.
- Grade 1 diesel is also known as winter diesel because it performs better than grade 2 diesel in cold weather conditions. It has a lower cloud point, which means it can operate without any issues at lower temperatures, making it ideal for use during winter.
- Grade 2 diesel, conversely, can gel up or clog at low temperatures and carry heavy loads and long-distance journeys.
Only use the 1-D or grade #1 diesel to get better fuel mileage in Duramax.
Incorrect Camber and Steering Alignment:
A well-aligned car is essential for good fuel economy, and camber and steering alignment play a crucial role. If your car’s camber or steering alignment is incorrect, it can lead to several problems that can reduce fuel efficiency.
Symptoms of Incorrect Camber/Steering Alignment:
- Unusual or noisy sounds coming from the car’s steering.
- Vehicle pulls to one side or another [right or left]
- Uneven tire wear
- Squealing tires
Take the vehicle to a mechanic or dealer to set the camber or steering Alignment, and don’t try to set it by yourself.
Air conditioner decreases fuel mileage as the conditioner consumes around 15 to 20 extra fuel. This means that if you’re constantly using your air conditioner, you may spend more on gas than you would otherwise.
- Use Ac when you needed otherwise, keep it off.
- Park the vehicle in the shade or under the tree.
If you frequently accelerate quickly from a stop or use the brakes more than necessary, your vehicle will likely consume more fuel than it needs to.
- If you drive at a slower pace or maintain a consistent speed while driving on highways, you can increase your mileage by 15 to 20 percent.
- If you drive within 10 MPH to 50 MPH, your fuel consumption will be low than the average.
Using the Wrong Engine Oil Grade:
GM recommends three types of engine oil.
- SAE 5W-40
- SAE 15W-40
- SAE 10W-30
You can find synthetic engine oil by checking the user manual.
Clogged, Damaged, or Faulty Fuel Injector:
A persistent issue with the fuel injectors can cause significant problems for owners. The problem lies in the design of the fuel injector, which is prone to failure over time and can lead to decreased engine performance. A bad injector can cause misfires, reduced power output, and even damage to other components over time.
Symptoms of a Fuel Injector Failure:
- Check engine lights
- Rough idling
- Engine vibration or misfiring
- Fuel leakage
- Decreased fuel efficiency
- Overheating and stalling engines
Cleaning the injector with cleaner is not a good solution because this issue will be again after 15 Km, so change the whole set of injectors. Due to the change injector, the fuel mileage and lifespan of the engine will increase.
Dirty/Faulty MAF Sensor:
A mass airflow sensor (MAF) is vital to a car’s engine management system. It measures the amount of air that enters the engine and provides real-time data to the Electronic Control Unit (ECU).
Symptoms of a Dirty/Faulty MAF Sensor:
- Check-engine indicator
- Dark exhaust
- A difficult start
- Trouble with acceleration
- Roughly idling
- Finally, poor fuel efficiency
There are two solutions including:
- Clean sensor with cleaner
- Change the sensors
Dirty/Faulty Oxygen Sensor:
A dirty/faulty oxygen sensor affects the fuel mileage negatively.
Symptoms of a Dirty/Faulty Oxygen Sensor:
- Stalling or misfiring
- Check-engine indicator
- Engine performance issues
- Poor fuel economy
- An overheated engine
- Emission tests were consistently failing.
- GM does not recommend the sensor cleaning; replace this after 70000 to 80000 Km.
Dirty Engine Air Filter:
A dirty filter does not throw air into the engine and increases fuel consumption.
Symptoms of Dirty Engine Air Filter:
- Unusual engine sound
- Decrease in engine power
- Engine jams
- Lower fuel efficiency
- The filter appears cloudy.
- Decreased HP
- Clean the filter after 7000 km and change the filter after 15000 km to decrease the bad fuel mileage.
Worn Brake Pads:
Worn brake pads are another reason for bad fuel mileage.
Symptoms of Worn Brake Pads:
- Clicking sound
- Increased stopping distance
- a squealing sound
- Braking causes vibration
- Hard brakes
- The truck’s nose pulls to one side during braking
- Change brake pads every 30000 miles.
Many people need to realize how much fuel their car consumes when idling. Idling a truck or car consumes up to a half gallon of fuel for more significant engines every hour. If you idle your car for an hour daily, you could waste 15 gallons of gas monthly.
Cold weather can exacerbate the issue by causing your engine to consume even more fuel as it strives to reach sufficient temperature. The colder the weather gets, the denser the air becomes, which increases aerodynamic drag on your truck and decreases its fuel mileage.
- If there is a red light or a traffic failure, turn off the ignition.
- Avoid idling your truck unnecessarily.
In the given guide, we deeply discuss why is my Duramax getting bad fuel mileage and try to solve this problem. So first identify the problem, then try to solve this problem.
What fuel mileage does a Duramax get?
In city driving conditions, a Duramax engine can achieve anywhere from 14 to 20 miles per gallon. If you plan to take your truck on the highway, you may see slightly better fuel economy, with estimates ranging from 18 to 25 miles per gallon.
How to Get Better Fuel Mileage in a Duramax?
Driving steadily is one of the easiest ways to improve your Duramax’s fuel economy. Avoid sudden acceleration or hard braking, as these actions consume more fuel than necessary. Instead, maintain a consistent speed while driving on highways or city roads. This simple trick can help you save up to 10% on fuel consumption.
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