April 2017 Archives - UnderhoodService
Hydraulic And Mechanical Tensioners

An automatic tensioner optimizes the belt tension in function and adapts to changes in the belt and engine characteristics. Engineers have designed two main systems to ensure optimal belt tension at all times. The first one is the “traditional” and most commonly used design, where a spring-loaded mechanical tensioner controls the belt tension.

GMC Tech Tip: EVAP Vent Solenoid Replacement (P0449)

Check engine light is illuminated with code P0449 from scan tool (Evaporative Emission Control System Vent Valve/Solenoid Circuit Malfunction).

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Fuel Injector Circuit Waveforms

The electric fuel injector has been around for more than 50 years. The principles of operation are simple. An electromagnetic coil moves a pintle in a chamber that has pressurized fuel on one side and a nozzle on the other. The coil is typically energized by a driver pulling the circuit to ground. As the coil is saturated by energy, the pintle moves upwards against a spring. This allows fuel to be injected into the engine.

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Air Conditioning Changes In 2017

As vehicle owners in many parts of the country begin using their air conditioning systems for the first time this year, some will be surprised to find their A/C system is not functioning properly or isn’t blowing out cold air like it used to.

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Human Resources: Putting It All On The Table

Hiring, firing and quitting are unavoidable events in the automotive repair industry. Everybody hates to deal with these aspects of the business because it can be risky on both sides of the table – not just monetarily, but emotionally, as well.

human resources
Being A True Professional

In the automotive repair profession, ASE certifications, manufacturer certifications and years of service are just some of the ways to distinguish one as a pro vs. a parts-swapping technician. I try to approach each and every job as a professional. This includes detailing my ­repair work and striving to make each repair as neat and orderly as possible.

true professional
Motor Mount Replacement Tips

Back in the old days, spotting a failed motor mount was easy. The cooling fan hit the radiator shroud and the engine would move side-to-side as the engine was loaded. Today, it takes a little more time to spot a worn motor mount. Why? Because a modern motor mount might do more than just hold the engine in place.

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Oil And Direct Fuel Injection

The oil in the crankcase of a direct fuel injected engine can make a huge difference in the health of the engine. The right oil can reduce carbon deposits on the intake valves and keep the engine healthy.

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GMC Blower History

Everybody loves a supercharger poking through the hood of a hot rod. But, these blowers originally made by GMC were used on diesel engines. These units were placed on the exhaust side of a two-stroke diesel engine to create a scavaging effect.

gmc blower history
Oil And Filter Service Guidelines

By some, oil filters are regarded as low-tech items that are all virtually the same. It may come as a surprise that nothing could be further from the truth. Today’s oil filter, whether it is a spin-on or cartridge type, possesses components which are specifically designed and engineered for individual applications. Today’s filter also offers significantly improved overall performance when compared to products made just a few years ago.

oil service guidelines
Subaru Forester Active Valve Lift System

Many thought the 2007 Subaru Forester had variable valve timing, even though it does not. Others were not aware of the ALVS that Subaru brought out in 2006. With that in mind, I’d like to share some insights into this very clever engine management strategy.

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Timing Chains In Hyundai Engines

Although Hyundai uses a single timing belt on its 2.7L V6 engines, its 3.3L, double-overhead camshaft engine is equipped with one timing chain for each camshaft and one drive chain for the oil pump. At first glance, a timing chain design allows engineers to shorten the overall length of the engine and reduce rotating friction.

timing chain hyundai featured