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  Spark: The Ignition System

  The ignition system’s most important job is sending electricity from the car’s battery to the spark plugs inside each engine cylinder. The system is composed of the following components:

  Spark Plugs. Using a huge electric jolt, of 40,000 volts, spark plugs set off your engine’s mini-explosions. Small devices that create bolts of lightning, the spark plugs light sparks that burn the compressed air-fuel mixture inside the engine’s cylinders. Spark plugs vary in price, but the more expensive plugs will last longer. They generally need replacing during “tune-ups” at 80,000 to 100,000 miles (see box, page 58), or per your owner’s manual.

  Ignition Coil (if applicable). The ignition coil sends electricity to the spark plugs.

  Distributor Cap and Rotor (if applicable). The distributor cap and rotor distribute electricity to each spark plug.

  Spark Plug Wires (if applicable). These wires help deliver electricity to the spark plugs from the cap and rotor.

  Air: Does Your Engine Have Boogies?

  I used to hate it when mechanics told me I needed to plunk down an extra thirty bucks to replace my engine air filter after I’d finally dragged myself in for an oil change. They’d say something about engine performance or gas mileage and I’d usually tune them out. This was a mistake. Engine air filters aren’t upsells. Remember how those mini-explosions inside the engine can’t happen without a ratio of fourteen parts air to one part fuel? The air in that mixture is sucked into the engine straight from the outside world. It’s the same air we breathe, and it’s filled with dust and dirt and contaminants.

  If you don’t change your engine air filter per your owner’s manual, your engine will have a hard time breathing, just like you would with a congested nose. And yes, as those mechanics told me, your engine performance will drop. Go too long, and you might even cause that check-engine light to come on. Ugh!

  The air filter prevents dust and dirt from entering the engine.

  The air intake system has two other significant parts: a throttle body and a mass airflow sensor. The throttle body controls the amount of air flowing into the engine. The mass airflow sensor measures the air being delivered to the engine, balancing things out by communicating with the PCM and the fuel injector to spray in additional gas. What you’re actually doing when you press on the “gas” pedal is opening up the throttle body to send more air into the engine; to maintain the correct air-to-gas ratio, the mass airflow sensor kicks in and talks to the PCM. Throttle body replacements can be tricky, and the part itself is expensive—repairs can run $500 or more.

  Signs of a Spark, Fuel, or Air System Issue

  PROBLEM: Your car turns on, but the engine won’t turn over.

  CAUSE: Fuel pump, fuel pressure regulator, ignition/spark system, or air delivery issues. Tow the car to your PCT for diagnosis.

  PROBLEM: Your engine misfires or runs poorly.

  CAUSE: Your spark plugs are worn down and you likely need a tune-up.

  PROBLEM: You lose power when you try to accelerate.

  CAUSE: Likely an air delivery issue. The throttle body or mass airflow sensor may need replacing.

  PROBLEM: You smell gas while you’re driving.

  CAUSE: Possible fuel and/or oil leak. Your check-engine light may illuminate. Take your car to your PCT as soon as possible. Driving around with a fuel leak can be very dangerous.

  PROBLEM: The check-engine light is illuminated on the dashboard.

  CAUSE: Your engine is not burning fuel efficiently.

  Know Your Engine

  The engine parts that allow the Eat, Burn, Belch cycle to eat up all that fuel and air include shafts, rods, belts, pulleys, and gears—internal parts that spin, rotate, or slide, rubbing up against each other as they work. All this movement causes wear and tear, and in this section, we are going to talk about how these parts work.

  The Crankshaft

  The crankshaft has the engine’s most important job: its spinning motion powers all of the car’s major systems. Inside the engine, the crankshaft is responsible for:

  Located inside the engine and connected to many parts inside and outside the engine by rods, belts, pulleys, and gears, the crankshaft causes internal and external parts to rotate along with it.

  • Opening the engine, so it can eat up air and fuel

  • Closing the engine after it lets out exhaust or belches

  • Burning the air and fuel inside the engine

  Outside the engine, the crankshaft:

  • Powers the transmission and wheels

  • Powers the AC compressor

  • Powers the power steering pump

  • Powers the water pump, which pumps coolant through the engine

  • Powers the air pump, which pumps air into the exhaust

  • Powers the alternator, which provides all electricity to the car while it is running

  Located along the bottom of the engine, the crankshaft is responsible for a tremendous amount of work, and it lasts for hundreds of thousands of miles. That’s a good thing. Engines are so complex, with so much riding on them, that we need them to be workhorses that will go the distance for the length of our vehicular relationships.

  Belts

  Two rubber belts connect the crankshaft to internal and external parts of the engine.

  The first, near the crankshaft, is an internal belt called a timing belt. When the crankshaft spins, the timing belt spins and activates the water pump. The engine is eating, burning, and belching; if the timing belt doesn’t drive the water pump, the serpentine belt does. Most cars have timing belts, but a few have timing chains, which look like thick bicycle chains and don’t need to be replaced.

  When the timing belt spins, an idler pulley also transfers power to the serpentine belt, a rubber belt outside the engine that is sometimes called a drive belt. (You located it under the hood on page 73.) The serpentine belt connects the engine crankshaft to all of the systems mentioned before—the pulleys that power the alternator, power steering, AC compressor, and more.

  The pulleys that transfer the engine's power are connected through a continuous belt (see serpentine belt); the belt assembly is mounted to the outside of your engine.

  Cylinders

  V8 isn’t just a mixer for your favorite brunchtime beverage.

  It’s also where the engine Eats, sucking air and fuel into separate compartments called cylinders before moving on to the Burn cycle.

  Combustion engines come in several types, but the most common are inline-four, V-6, and V-8. The numbers reference the quantity of cylinders inside the engine. An inline-four engine has four cylinders, a V-6 has six cylinders, and so on. The more cylinders in your engine, the more fuel you will need—and the faster and more powerful your car will be. Trucks, SUVs, and race cars tend to have V-8 engines, which give them the power to accelerate quickly or to haul or tow heavy objects.

  What does the letter V have to do with it? That’s the shape the cylinders make as they sit inside the engine. There are also inline-five, inline-six, V-10, and V-12 engines, but they are less common and usually seen in European models, sports cars, Jeeps, and luxury vehicles.

  An inline-four engine

  A V-6 engine

  Do You Need Horsepower?

  You’ve definitely heard the term, and you’ve probably wondered what it means. Essentially, horsepower is the amount of power the car can produce. And only people who buy cars for speed and power need to worry about it.

  Horsepower also has to do with the amount of power the engine can generate by playing with the Burn portion of the Eat, Burn, Belch cycle. Engines that set fuel on fire at higher temperatures also efficiently compress fuel and air for added power. These engines take premium gas and other premium fluids designed to burn at higher temperatures, and they’re outfitted with spark plugs that spark at higher temperatures. The greater your engine’s power, the greater the torque (the power that is transferred to the wheels), the faster the car accelerates a
nd drives.

  The Tachometer and Crankshaft

  Wouldn’t it be cool if the tachometer were an app telling us the location of the nearest taco place? Instead it’s the dashboard instrument that measures how fast the crankshaft inside the engine is spinning.

  When you’re idling and only a tiny bit of gas is being fed into the engine, the tachometer runs around a 1. On a highway, it hovers around 2.5 or 3, and on a hill, the dial can point to 4 or 5. Sound slow? Those numbers actually stand for thousands of rpm (revolutions per minute). At highway speeds, your crankshaft is spinning 2,500 to 3,000 times per minute.

  Whoa! That crankshaft is one fast piece of machinery. The faster it rotates, the faster the Eat, Burn, Belch cycle spins, and the more lubrication is required. Getting the needle to 7 or 8 is what we call redlining, when the crankshaft is moving so fast that the whole engine is becoming unstable. In the redline zone, the engine’s internal parts are spinning way too fast, and the engine may become unstable and blow up.

  To tell you the truth, most drivers don’t pay much attention to the tachometer, and that’s okay. But if you’re concerned about saving money on gas, you’ll want the tachometer hovering around 2 as often as possible. And if you notice the tachometer wildly jumping up and down, especially during acceleration, there may be a problem with the amount of air or fuel being delivered to your engine.

  INTERNAL AND EXTERNAL ENGINE PARTS MAINTENANCE AND REPAIRS

  PART

  ISSUE

  FIX

  TIMING

  COST

  Timing Belt

  Made of rubber, timing belts don’t last forever

  A timing belt’s location inside the engine makes it difficult to access, so replacing one is a very expensive repair. Note: If your car has a timing chain, no maintenance is needed

  PCTs cannot routinely check to see if a timing belt is going bad, so we recommend replacing yours around 100,000 miles. Ignore this important maintenance task and the timing belt can fail on the road, causing far more expensive damage

  Look to spend at least $650 to replace

  Drive/Serpentine Belt and Pulleys

  The drive or serpentine belt and pulleys that attach the alternator, power steering pump, and other parts of the engine crankshaft will fail from use over time. Because the belts are made of rubber for flexibility, they will wear down. The pulleys will seize up and stop spinning

  Look for cracks in the belt, perpendicular to the ribs. The car may make a high-pitched or chirping noise when you first turn it on, while it is in drive, or during acceleration. When you hear this, it’s time to replace the belt and one or more pulleys

  Belts reach the end of their life span at around 60,000–120,000 miles, depending on the vehicle model

  Normally less than $150

  Gaskets and Seals

  Gaskets and seals prevent oil and coolant from leaking inside and outside the engine. They will fail and break down from use over time, causing fuel leaks

  Replace gasket or seal

  Shouldn’t fail before 60,000–80,000 miles

  $500+. Could go over $1,500 if labor is intensive

  Engine Oil and Oil Filter

  All internal parts must be lubricated for optimal functioning

  Your PCT will drain the old oil, replace the oil filter, and put in fresh oil

  See your owner’s manual

  $40–$95, depending on the oil

  Oil Pump

  Wears over time. If the oil pump fails, pressurized oil won’t be pumped through the system

  Replace

  Your dashboard oilcan light will alert you to a failure

  $750+

  Oil Pan and Gasket

  The oil pan gasket can fail, causing oil to leak from the oil pan. The oil pan itself can fail from corrosion and will need to be replaced

  Replace

  Variable

  $750+

  No Lube, No Action: Your Engine’s Lubrication System

  The engine’s Eat, Burn, Belch cycle happens at incredibly high speeds, generating a huge amount of heat and friction. It’s not just the explosions that make things so hot, it's also the demonically fast spinning of the internal parts and the firing of the spark plugs. Recall how fast the crankshaft is spinning: three thousand times per minute when you are driving. All that motion and friction create tons of heat. Enter oil, your engine’s lifeline, the essential fluid that lubricates the engine to protect it from friction. Engine oil keeps things working in harmony by creating a slippery coat that allows internal parts to move with ease. Without it, your engine is toast. So get to know your under-the-hood lubrication system, which contains the following components.

  Engine Oil. Fluid that lubricates moving and sliding internal engine parts (also known as motor oil). Because engines contain many moving and sliding parts, their inner workings must be lubricated to reduce friction and wear. It is essential to keep oil running through your engine at all times. See page 97 for information on what type of oil to feed yours.

  Oil Pump. A pump turned by the engine crankshaft to move pressurized oil through an oil filter and to the engine.

  Oil Pan and Gasket. Where the oil is stored. Most cars hold 5 liters, but larger cars hold more. The oil pan attaches to the bottom of the engine and is sealed with a rubber gasket to prevent leaks.

  Oil Filter. Strains dirt and foreign objects from oil before they reach the engine.

  TIP: Have you ever noticed that when you’re overdue for an oil change, your engine runs a little rough? And that as soon as you get an oil change, the engine feels like it is purring? The next time you are due for an oil change, don’t procrastinate.

  Conventional Oil, Synthetic Oil, or Synthetic Blend?

  Pre–auto tech Patrice didn’t take too kindly to being asked what type of oil she wanted in her car. “Huh? Shouldn’t you know that?” I’d ask the tech at the quick-lube facility in a slightly irritated tone. He’d try to explain the difference between synthetic and conventional, but I’d cut the conversation short when I found out synthetic was going to be more than twice the price. “Nah, I’m good. I’ll just take the thirty-five-dollar oil change, please.” No one was going to upsell me!

  But synthetic oil is not an upsell. Depending on your car, it may be helpful or even necessary.

  Do you drive a luxury car? If the answer is no, your car most likely uses regular oil. Conventional oil or regular oil is what most cars (think Hondas, Fords) take today. You can get an oil change with regular oil for less than forty dollars almost anywhere in the United States.

  Luxury cars (think Lexus, Mercedes, BMW, Audi) take synthetic oil, sometimes called full synthetic. Created by oil engineers who used additives to manufacture an oil far superior in quality, synthetic oil lasts longer, performs better, and is cleaner than conventional or regular oil. It is also two to three times the price. Expect to spend at least sixty-five and as much as ninety-five dollars on a synthetic oil change.

  Synthetic blend, aka high-mileage oil, is a combination of conventional and synthetic oils. Once your car has accumulated a large amount of mileage (100,000 miles or more), you may want to consider using this blend to get some of synthetic’s superior performance at a lower cost. Most new cars require synthetic blends. Expect to spend forty-five to sixty-five dollars on a synthetic blend oil change.

  If conventional oil is a regular manicure, synthetic is a fancy gel situation. If you have a luxury car, you must use synthetic oil, so no regular manis for you. For everyone else, the choice of regular or synthetic (high-mileage) oil just depends on whether you want to spend a little bit of extra cash for a better product. Gel manicures are going to be higher quality and last longer, but a standard car doesn’t really need synthetic or a blend/high-mileage oil, just like nobody really needs a gel manicure.

  Switching between synthetic and conventional oil isn’t a cardinal sin. However, mixing the two types of oil is a no-no. If you need to add oil to the engine but aren’t draining out the exis
ting oil, stick with the same grade you were using before.

  Oil Type

  What do the alphanumerical combinations 10W-30 and 5W-20 mean to you? These letters and numbers specify different types of engine oil, which vary in viscosity and thickness. To find out the oil type your car requires, check the oil filler cap on your engine or refer to your owner’s manual. You can also search online or go to a parts store and give them your car’s year, make, and model. P.S. Some people may call it weight, but the W stands for winter, meaning that the oil is okay to use in harsh cold-weather conditions, like negative temperatures.

  Oil Changes vs. Refills

  An oil refill is something any #shecanic can accomplish if her oil is low, requiring nothing more than a bottle of engine oil and a funnel. An oil change is something a mechanic performs when the oil has reached the end of its life (normally 5,000–10,000 miles). Oil changes involve parts and a whole bunch of tools—a wrench that fits the oil pan bolt, an oil filter wrench, a jack for the car, two jack stands to lift the car, a bucket to put the used oil in—not to mention a means of safely and legally disposing of the used oil. The parts alone will add up to the cost of getting the job done at your local repair shop, so changing your own oil doesn’t come out as a win unless you regularly perform other maintenance and repairs on your car.

  Signs of a Lubrication System Issue

  Any issues involving engine oil need to be addressed ASAP, before they cause expensive damage to your engine. Look out for the following signs of a problem.

  PROBLEM: Oil leak

  CAUSE: Oil leaks often occur around the engine’s seals and gaskets. You’ll be able to see an oil leak, either under the hood or underneath the car. Have a mechanic check it out ASAP to determine the extent of the leak and how much it will cost to repair.