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Common Mack E7 Engine Problems

The Mack E7 engine has a history of problems, ranging from camshaft failure to injector failure. Some owners reported mileage-to-failure rates of 17 miles or less. Another common problem is fuel system wiring that pulls combustible vapors into the air intake. But the big question is: What’s the cause of this problem? And how can you fix it?

Injector failure is uncommon

Despite the recurrent problems associated with the Mack E7 engine, injector failure is relatively rare. Mack engineers have known about the problem for many years and are unsure of why it keeps happening. Nonetheless, there are several reasons why injector failure is so common with Mack engines. Listed below are some possible causes:

The Econovance system improved fuel efficiency and combustion productivity. Mack engineers implemented the Econovance system only in the E7 engine, and did not incorporate it into other production lines. This new system also improved the oil viscosity. These factors combined to make the Mack E7 engine a good choice for a number of industries. It is also capable of hauling 1,500,000 miles hauling a full load.

Another potential cause of injector failure is a buildup of coking deposits. These deposits can interfere with the fuel spray, resulting in decreased fuel economy and loss of power. These deposits can be removed by cleaning the injectors or replacing them entirely. But even if injectors are not the source of engine problems, they can be a major expense. If you have any doubts, consult a mechanic for assistance.

While outright injector failure is not common in mack E7 engines, it is a potential cause of many other’machine-related’ problems. Injector failure can lead to excessive smoke, low fuel efficiency, and engine damage. A reconstructed injector valve can be a simple, inexpensive solution for injector failure. With basic hand tools and a brass bristled brush, it’s easy to clean and restore your vehicle’s performance.

Camshaft failure is common

One of the most common engine problems that occur in the Mack E7 is camshaft failure. This problem usually occurs when there’s a loose rotating part that strikes the camshaft. The camshaft might have cracked during shipping or improper handling prior to installation. In the event of camshaft failure, it is important to replace it as soon as possible. If this problem does occur, there are several steps to take.

First of all, it is important to know that the Mack E7 engine is not designed for high-speed operation. The engine is designed to run at low-to-moderate speeds and is typically capable of hauling about 1,500,000 miles before requiring a major overhaul. Mack E7 engines are used in mining, oil and gas, agriculture, construction, pump and compressor applications, and power generation.

Next, consider the location of the problem. Camshaft failure can be the result of improper lubrication. Proper lubricant is usually included with your new cams. Make sure to apply lubricant to every surface of the cam lobes and the bottom of every lifter face. If your camshaft is roller-tappet, you only need to lubricate the lifters, not the camshaft. Similarly, the distributor drive gears must be lubricated.

Fuel system wiring could cause combustible vapors to be pulled into the engine’s air intake

Combustible vapors can be drawn into an engine’s air intake through the wiring in a fuel system. These vapors can be dangerous, as they can be mixed with the air in the intake. In addition to being flammable, combustible vapors can also cause severe damage to an engine’s wiring.

The first diagnostic step in diagnosing a fuel system problem is to listen to the fuel pump. When the ignition key is turned to the run position, you should hear a humming noise coming from the fuel tank. If the sound continues for a couple of seconds, the fuel pump is running. If the sound stops, the next step is to check the fuel pressure and electrical circuits.

Another potential problem is a leaking fuel pressure regulator. These regulators could be defective or leaking, causing combustible vapors to be pulled into the engine’s air intake. A faulty regulator could cause a lean or rich air/fuel mixture that affects the engine’s performance and emissions. It can also lead to a malfunction in the powertrain control module (PCM).

In addition to a leaky fuel pump, fuel system wiring could cause combustible gas vapors to be drawn into the air intake through the engine’s wiring. If this happens, the fuel pump could be in direct contact with hot engine parts, resulting in a fire or a gas leak. In addition, fuel is best kept away from the engine’s air intake, because combustible vapors can ignite if an electrical component sparks.


The reliability of a Mack E7 engine can be questioned. The engine was developed one generation too far. The problem was with the turbochargers, which failed at an average rate of 17 miles. In the past, this problem was only associated with Volvo D12 and D16 engines, but now Mack has its own version. But it doesn’t mean that they are immune to problems. Mechanics are becoming increasingly good at replacing turbos.

The Mack Corporation introduced the E7 engine in 1988. The E7 engine was initially intended for commercial 18-wheel trucks. In the late 80s, engineers conceptualized the E7 engine and it went on to become the most popular industrial diesel engine. Later, the company expanded its application with the CH Series. Despite its widespread use, this engine suffered from a variety of problems. Although this engine has a long history, its reliability has been questioned by some users.

The Mack E7 engine was designed to meet the strict emissions standards set by the Environmental Protection Agency (EPA). The Econovance system was only used on the E7 engine and was not used on other Mack production lines. Econovance technology improved the air/fuel mixing ratio, improved combustion productivity, and reduced emissions. The E7 engine also featured upgraded high rated steel crest articulated pistons and wet-dry liners for long-term durability.

Fuel efficiency

While the fuel efficiency of Mack E7 engines varies, there are common fuel-related issues that can cause a failure. Injector failure, for instance, is not uncommon, but can lead to costly repairs. In the meantime, the fuel-pump failure of Mack E7 models is a common problem. While this is a costly issue, it is manageable and can easily be solved. Inspecting the fuel pump and injectors will help you pinpoint the problem.

The most common fuel-efficiency issues of the Mack E7 engine have to do with the turbochargers. Despite the E7’s turbos being made by Volvo, the failure of one of these components has led to problems with the Mack version. A fleet manager with an E7 reported that their vehicle had a low mileage-to-failure rate of 17 miles. Mack engineers noted that this issue was a problem caused by the variable-geometry turbocharger, which is a critical component in the engine’s fuel-efficiency. Although these issues are common in modern trucks, Volvo and Detroit Diesel engines are not without their problems as well.

The original E7 engine was turbocharged and featured an air-to-air aftercooling system. In 1990, Mack introduced the Econovance variable-injection-timing system to optimize fuel efficiency and reduce emissions. This system was only used in the Mack E7 engine, however. The Econovance variable-injection-timing system improved the air-fuel mixture and reduced emissions. It improved the oil viscosity by increasing the air flow.

The fuel efficiency of Mack E7 engines ranged from 250 to 400 horsepower. Some were even boosted to 1,660 foot pounds of torque. Although most Mack E7 engines were water-cooled, some of them were air-cooled. The Mack E-Tech engine, however, is still produced today. It is a six-cylinder, multi-system cooled engine with a typical horsepower rating of 250-400 hp.