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Why OEMs Are Investing In Lithium-Ion Battery Recycling
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By OReilly Auto Parts
Automotive Shock and Strut Overview | What do they do and why are they important?
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By NAPA
Is your car not shifting gears like it used to? An automatic transmission makes driving much less complicated than the manual gear (stick shift) alternative. But that convenience comes at the price of complexity. When an automatic transmission equipped car won’t shift gears, there could be several potential issues. These issues can range from a simple fix to needing a complete transmission rebuild. Below is technical expertise on “Why is my automatic car not shifting gears?”
Low Transmission Fluid link hidden, please login to view
Your automatic transmission relies on hydraulic fluid pressure to operate. The pump pulls
link hidden, please login to view from the transmission pan reservoir to actuate different components. If the transmission fluid level gets low enough, the pump will be unable to push fluid where it needs to go. Even worse, the pump will pull air into the system, which could lead to a lack of lubrication that damages parts. If you are lucky, your vehicle has a transmission fluid dipstick so you can easily check the fluid level according to the instructions in the owner’s manual. If your vehicle does not have a transmission fluid dipstick but is “
link hidden, please login to view”, that doesn’t prevent you from checking the fluid level. In most cases, the fluid can be checked via a fill plug, but the transmission has to be at a certain temperature and the vehicle must be level. This isn’t an easy task, so it might be best to have your local link hidden, please login to view do it for you. Faulty Shift Solenoid
We just mentioned how an automatic transmission relies on pressurized fluid to operate, but that fluid also needs to be routed to where it is needed. In a modern, electronically controlled automatic transmission, shift solenoids control the flow of transmission fluid. If the shift solenoid is faulty, then the fluid won’t be routed to the desired shift actuator. In older non-electronically controlled transmissions, shifting was controlled by shift valves, but the idea is the same. Shift solenoids can wear out or get stuck, leading to a no-shift condition. Fixing a faulty shift solenoid usually requires removing the transmission fluid pan to access the transmission valve body.
Low Transmission Fluid Pressure
You should be seeing a pattern of how important hydraulic fluid is to the operation of an automatic transmission. If the transmission fluid level is fine, there may still be a problem with the fluid pressure. Low fluid pressure can be caused by a worn out pump, clogged fluid passages or a clogged transmission fluid filter. A lack of shifting car gears due to low fluid pressure usually means it is time for a
link hidden, please login to view. If the problem is with the pump itself, then you are probably looking at a transmission rebuild. Bad Transmission Control Module
Most modern automatic transmissions have an electronic
link hidden, please login to view (TCM). The control module takes input from various sensors, and decides how the transmission should react. Depending on where the control module is mounted, it can lead a very hard life. Extreme temperatures, vibrations, leaking fluids and sometimes even how the circuit board is built can all lead to failures of microchips and other electronic components. If the check engine light is on while you are having shifting problems, the TCM may be the issue. Broken Shift Cable
Each time you drive, the shifter is moved at least twice, once for driving and again for park. That movement adds up over the years. While an automatic transmission doesn’t have the complicated shifting mechanism of a manual transmission, there is usually a physical connection between the shifter and the transmission. Modern
link hidden, please login to view usually have plastic components that can break down over time. There may also be bushings that get worn out. The shift cable itself is usually metal and rarely breaks, but the pieces connecting it to the transmission can possibly fail. Shift Lock Engaged
If the car is not shifting into gear from park, then the issue might be the gear shift interlock. Most modern vehicles have a lockout on the automatic gear shifter that requires the brake pedal to be pressed first. If the brake pedal isn’t pressed, the shifter won’t move. It is possible that the brake pedal sensor doesn’t read that the pedal is pressed, or a break in the shift interlock circuit interrupts the connection. The shift lock can be
link hidden, please login to view. Worn Out Bands
Just like how brake pads can wear out, so can the friction materials inside the transmission like the bands. Transmission bands hold certain components in place, while others are allowed to rotate. When this happens, the transmission won’t go into certain gears. Unfortunately worn out bands usually mean a complete transmission overhaul. Material from the worn out bands can make their way into sensitive fluid passages, clogging them or causing accelerated wear
Failed Throttle Sensor
This one may seem odd, but gauging how much throttle input the driver is giving makes a big difference in how the transmission acts. Whether the input is from a
link hidden, please login to view or a cable, if the driver pushes down the gas pedal, the transmission needs to change gears. But if that input isn’t received, the transmission has no idea what the driver wants to do. If the transmission doesn’t know the driver is hitting the gas, it might not shift into the next gear. Even worse, on some older transmissions, if the transmission isn’t linked correctly to the throttle input, severe damage can be done. If your transmission isn’t shifting like it used to, simply head to your local
link hidden, please login to view center. Our team of ASE-certified technicians have the expertise and training to diagnose your automatic transmission issues. As a bonus, your repair is covered by our free 24-Month/24,000-Mile link hidden, please login to view (parts and labor on qualifying repairs and services), which spans across the entire nationwide NAPA Network, including 17,000+ NAPA Auto Care center locations. Photos courtesy of
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By Counterman
Spark plugs are the “canary in the coal mine” of the combustion chamber. The electrodes and porcelain can reveal short- and long-term problems if you know where to look.
Most OE spark plugs have a life of more than 50,000 miles, thanks to electrodes that contain precious metals like platinum and iridium. OEMs consider the spark plugs a part of the emissions system on most modern vehicles.
If the plugs fail sooner than the recommended interval, it’s important to solve the problem before installing new plugs. If you’re replacing spark plugs to solve a misfire problem, the car will be back.
But first, what causes spark plugs to foul quickly? What does a fouled spark plug look like, and what is spark plug fouling?
Carbon Fouling
If the spark plugs have a matte black or grey appearance, it could be carbon fouling – something typically caused by a fuel mixture that’s too rich.
During normal combustion, most of the fuel oxidizes and changes into carbon dioxide and carbon monoxide gas. When there is more fuel than oxygen, the carbon in the unburned fuel polymerizes into carbon deposits. These molecules like to stick to the hot spots in the combustion chamber, and this includes the spark plug’s tip and insulator.
Curing the problem will typically point to the fuel system and how the engine is breathing. If a fuel injector is clogged or sticking open, extra fuel can cause carbon problems.
If the mass airflow sensor or oxygen sensors aren‘t accurately reporting the air that’s coming into the engine or the oxygen content in the exhaust stream, it could cause a rich-running condition that can cause carbon to foul the spark plugs.
Another factor is how the air flows past the valves. If the air is restricted or has to flow past carbon deposits on the intake valves, it will be turbulent and disturb the flame front and fuel-droplet size in the combustion chamber. This means that the fuel injected into the intake port or combustion chamber won’t entirely burn.
Oil Fouling
Oil fouling of a spark plug typically results in a shiny, black appearance. If enough oil is in the combustion chamber, the deposits can build up on the tip, porcelain or shell.
If you can’t determine if it’s carbon or oil fouling, smell the plug; it will smell like engine oil. The oil can come from the piston rings, valve stem seals or the positive crankcase ventilation (PCV) system. Leaking piston rings can be diagnosed with a leak-down test. If one cylinder has oil fouling, a relative compression check can help to assess mechanical issues with that cylinder.
Malfunctioning PCV systems are becoming a leading cause of oil fouling in modern engines. These systems have become more than just a spring-loaded check valve. Modern systems can separate oil from the crankcase vapors and electronically regulate when the engine ingests the vapors.
Some PCV systems have a heater to ensure that the valve doesn’t freeze under certain conditions when condensation is present. If the valve does freeze, it can cause higher-than-normal crankcase pressure. This can cause oil to be forced past the valve seals.
If the PCV valve is stuck open, the excess vapors and oil droplets can quickly foul the spark plugs.
A failed turbocharger can be another source of spark plug oil fouling. The seals on the turbine shaft are robust, but they can be victims of heat and poor oil quality. The oil that lubricates the shaft can enter into the pressurized intake and eventually the combustion chamber.
OEMs have issued technical service bulletins concerning excessive oil consumption. Most of these problems relate to cylinder deactivation and variable valve timing (VVT).
The main culprit in these problems is vacuum generated in the cylinders that sucks engine oil past the rings and into the combustion chamber. On vehicles with cylinder deactivation, the deactivated cylinder has negative pressure and draws oil droplets in the crankcase past the ring and eventually into the converter. This has happened on some GM and Honda engines.
On some vehicles with VVT (typically on the exhaust and intake cams), the valve timing could produce higher-than-normal vacuum pressures that could suck oil past the rings. This was the case for some recent Toyota, Honda and GM models. The customer would report increased oil consumption that exceeded one quart every1,000 miles.
Beyond the oil getting past the rings, the oil trapped in the rings can become carbonized and cause damage to the cylinder walls. This can lead to even more damage and more oil consumption. In some cases, the oil consumption results in a low-oil condition that would cause damage to the bearing surfaces.
Coolant Problems
Internal coolant leaks can foul a spark plug and cause a misfire. The problem could be a leaking intake manifold or a head gasket, and the fouled plug might be localized to one or two adjacent cylinders. The burned coolant leaves ashy, white deposits on the electrodes and insulator, creating hot spots that could cause pre-ignition and a misfire code to be set.
When the plug is pulled, it might have a chalky appearance on the ground strap and center electrode. Modern coolants don’t cause this type of buildup quickly, due to the reduction of phosphate, zinc and other additives that can contaminate the catalytic converters.
In the past, the converter would become clogged and stop the engine before significant damage occurred.
Unfortunately, formulations mean that drivers can run a vehicle with a coolant leak for several thousand miles, while the plug becomes slowly fouled.
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