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Q: What is the leading cause of AC compressor failures?

A: The most common cause of a compressor failure is inadequate lubrication. This may be the result of a refrigerant leak that allows compressor oil to leak out of the system. Typical leak points are hoses, hose and pipe connection (O-rings and flange gaskets), the evaporator, condenser or the compressor shaft seal. An electronic leak detector or dye should be used to find the leak so it can be repaired.

Lubrication problems can also be caused by a blockage (typically the orifice tube) that prevents refrigerant and oil from circulating through the A/C system.

Using the wrong type of compressor oil for the application or the wrong amount can also lead to premature wear and failure.

A seized compressor won?t turn when the magnetic clutch engages, and you may hear squeals of protest from the drive belt. Or, the belt may have already broken or been thrown off its pulley when the compressor failed.

A compressor may also have to be replaced if it is leaking, making excessive noise or not working correctly because of an internal valve or piston failure. Some compressors are naturally noisier than others, but loud knocking noises can sometimes be causes by air in the system (the cure here is to vacuum purge the system to remove the unwanted air, then to recharge the system with refrigerant). Metallic noises and bearing noise are usually signals that the compressor has reached the end of the road.

Debris left over from a previous compressor failure can also cause a newly installed compressor to fail. To reduce this risk, the A/C system should be inspected and flushed to remove contaminants. The accumulator or receiver/drier should also replaced. Installing an in-line filter in the high pressure liquid line, and an inlet screen filter in the suction hose can also reduce the risk of debris causing a repeat failure.

Q: Why do fuel injectors get dirty?

A: Fuel injectors can become clogged with fuel varnish deposits when gasoline contains inadequate levels of detergent to keep the injectors clean.

To reduce the cost of gasoline by a few cents per gallon, some gasoline suppliers reduce or even eliminate the amount of detergents in their fuel, or they use less expensive (and less effective) additives. Commonly used additives in gasoline include polyetheramine, polysibutylamine succinimide and polyisobtylene. Some of the additives that keep injectors clean may form deposits on the intake valves. To prevent this from happening, additional additives called ?fluidizers? may be added to the fuel. Over time, fluidizers can form additional deposits in the combustion chambers. This may raise compression and increase the risk of detonation (spark knock).

To keep fuel injectors clean it takes about 1,000 parts per million (ppm) of dispersant-detergent in the fuel. Yet, as much as 85 percent of the gasoline sold in the U.S. contains only about 1/10 of the recommended dosage (only 100 ppm) of the required additives. Consequently, fuel injectors, intake valves and combustion chambers all get dirty and require cleaning by adding some type of aftermarket cleaning product to the fuel tank.

Over-the-counter fuel system cleaners come in various formulations. The best advice is to recommend a product designed for a particular application. Some additives are more for preventative maintenance and help supplement low levels of detergent that are in some brands of gasoline. Other products are formulated to remove deposits that have already formed and may be causing drivability problems.

Always follow the directions on the product label as far as dosage is concerned. Typically, a 12oz bottle of fuel system cleaner can be used to treat 10 to 20 gallons of gasoline.

Q: Which is best: ceramic or semi-metallic brake lining?

A: It depends what you mean by the word ?best?. What?s best for one vehicle application may not be the best for a different application. The type of friction material that works best will depend on the type and size of the vehicle, how the vehicle is driven and most importantly, what the consumer expects in terms of brake performance, pedal feel, noise and lining longevity. The short answer, therefore, is that no one friction material is best for all applications and situations.

Someone who drives a big Chevy Suburban and tows a boat or horse trailer on the weekends is a different kind of brake customer than someone than someone who commutes back and forth to work on the open highway in a Kia Rio. Likewise, the performance-oriented customer who wants brakes that can stop his BMW on a dime is a different kind of brake customer than the Buick driver who doesn?t want to hear any squeals when she applies the brakes.

According to JD Powers survey, the most important things that brake customers want are in the following order:

1. Stopping power

2. Good pedal feel (no soft or mushy pedal)

3. Quiet operation(no squeals or other objectionable noise)

4. No brake pulsation (which is a function of rotor wear & runout)

5. Durability

To satisfy these expectations, brake suppliers use a variety of friction materials high-content ceramics, low-metallics, semi-metallics, and nonasbestos organics.

Ceramic fibers are added to some friction materials because the fibers have stable and predictable friction characteristics. Chopped steel fibers in semi-metallic linings, by comparison, are added to dissipate heat and are typically used in applications where higher braking temperatures are encountered.

Ceramic provided a consistent pedal feel that is the same whether the pads are hot or cold because the coefficient of friction doesn?t drop off as quickly as semi-metallics. NVH (noise, vibration and harshness) is also less with ceramics, so the brakes are significantly quieter ? and kinder to rotors, too.

Low dust is another desirable characteristic of ceramics. The color of the dust given off by a high ceramic content linings is typically a light gray and is less visible on wheels (unlike some NAO and low metallic friction materials that produce a dark brown or black dust that clings to wheels).

An estimated 40 percent of new vehicle models currently sold in North America now have ceramic brake linings as original equipment.

Though ceramics have a number of advantages compared to semi-metallics, ceramics may not be the best choice for heavier vehicles such as SUV?s and trucks that are used for towing and hauling heavy loads. For these applications, semi-metallic brakes typically work better.

Semi-metallic friction materials with a high iron or steel content (50 to 60 percent) can handle heat much better then ceramics, low-metallics (those with 15 to 35 percent steel content) or non asbestos organic (NAO) materials. Up to about 500 degrees, ceramics wear better then semi-metallics. But above 500 degrees, semi-metallic linings perform and wear best ? but the trade-off may be increased noise and rotor harshness.

The best advice is to follow the application recommendations of your brake suppliers. As a rule, most recommend replacing same with same. If a vehicle was originally equipped with ceramic pads, the old pads should be replaced with the ones that use a similar ceramic formula.

Installing semi-metallic pads on applications that were originally equipped with ceramic pads is usually not recommended because switching to semi-metallic pads may increase noise and rotor wear.

Q: Aren?t most ceramic brake linings pretty much the same?

A: Absolutely not. Ceramic is a buzzword that?s often misused and abused, and generally confuses many people. There are different types and shapes of ceramic fibers. Which fibers are used and how they are combined with other ingredients determines the noise, wear and braking characteristics of the base friction material. The size of the ceramic fibers is also important. Some brake suppliers only use ?fine? ceramic particles that that measure 20 microns or smaller while others use particles that range in size up to 80 microns. Those who use smaller particles say they reduce noise and rotor wear.

Some brake suppliers use high ceramic content friction formulas while others use ?ceramic enhanced? formulas that only add a small amount of ceramic to an existing conventional formula so it can be marketed as a ?ceramic? product.

Ceramic compounds can be very complex and may use 18 to 20 different ingredients in a formula, including various fillers and lubricants that are added to help dampen vibrations and noise. Some ceramic formulas may contain up to 30 percent iron to help dampen noise while others use little or no iron.

The selection of the resin and filler materials are also important as are the other ingredients that go into the friction compound. Consequently, one ceramic friction compound may perform very differently from another on the same vehicle. That?s why leading brake suppliers ?application engineer? friction compounds for specific vehicle applications. They develop different friction formula for different vehicle platforms.

Q: What?s the purpose of slots, chamfers and shims on ceramic brake pads?

A: Slots, chamfers and shims are not used on many premium pads (not just ceramic) to reduce noise.

Chamfers are angled or beveled edges on the leading and trailing ends of the pad that reduce ?tip-in? noise when the brakes are first applied, and change the harmonics of the pad to further dampen noise. Slots are grooves cut vertically, diagonally or horizontally in the pads. Vertical slots reduce stress that might cause the pads to crack. Angled slots or multiple slots are typically used to dampen low frequency noise. Insulator shims may be used to provide additional dampening in some applications. The shim may be laminated inside the pad or attached to the back of the pad.

Q: Which should last longer, brake rotors or pads?

A: Theoretically, the rotors should outlast the pads. In fact the rotors should last several sets of brake pads, but they often don?t. Excessive rotor runout, uneven rotor wear, the appearance of hard spots and/or heat damage (cracking, glazing and discoloration) can all make good rotors go bad.

Unless the rotors are in like-new condition and show no grooving or wear, resurfacing is always recommended when the pads are replaced. Resurfacing can clean up normal wear (minor scoring) and other surface imperfections. But if the rotors are heavily worm (thickness is at or below the minimum thickness or discard specification on the casting), are deeply scored, cracked, damaged or have hard spots (discolored or glazed patches on the surface), they must be replaced.

Q: What is a common symptom of brake rotor trouble?

A: Pedal shudder when braking. The cause may be too much lateral (sideways) run out and/or variation in rotor thickness. Run out occurs when the rotor wobbles as it spins. This can be caused by run out in the hub, run out in the rotor, rust or dirt between the rotor and hub, or uneven torque of the lugs that distort the rotor and hub (which is why lug nuts should always be tightened to specifications with a torque wrench, not a impact gun.

Q: Should a new rotor be resurfaced before it is installed?

A: No. Resurfacing is absolutely unnecessary and only shortens the life of the rotor by making it thinner. New rotors are machines to OEM specifications and are ready to install right out of the box

Q: What is the recommended finish for late model rotors?

A: Most new OEM rotors today have a surface finish between 30 and 60 inches RA (roughness average), with many falling in the 40 to 50 RA range. Some OEM specifications say that anything less than 80 RA is acceptable.

It?s almost impossible to see or even feel much of a difference between an 80 RA finish and a 40 RA finish. But such differences can, and do, affect brake performance ? and smoother is always better. Achieving a smooth finish requires sharp lathe tools and proper cutting speeds. Cutting rotors too quickly to save time may produce a surface finish that?s too rough and noisy. If you can feel grooves on the surface of the rotor with your fingernail, the rotor is probably too rough.

If you resurface rotors in your store:

  • Use the shallowest possible cut to extend the rotors life
  • Make sure the rotor is properly supported and mounted squarely on the lathe arbor to minimize runout.
  • Use adapters or oversize bellcaps to support ?composite? rotors otherwise the rotors may flex and chatter.
  • Use a vibration dampener to reduce noise and the tool chatter.
Use sharp lathe bits and a slow feed rate to produce a high-quality finish. A spindle speed of 100 to 150 RPM with a cross feed rate of 0.002 in to 0.005 in. per revolution should produce a smooth high quality rotor finish.

Q: What does a cabin air filter do?

A: A cabin air filter is like a filter on a home furnace or air conditioner. It removed dirt, dust and pollen from air that enters the passenger compartment through the vehicles HVAC (heating ventilation and air conditioning) system. The filter also helps keep the A/C evaporator clean. This allows the A/C system to cool at peak efficiency and reduces the buildup of contaminates on the evaporator that contribute to the growth of microbes that can cause musty odors.

Some cabin air filters are also ?combination? filters that also remove odors, diesel fumes and other pollutants. Combination filters typically have a layer of activated carbon that reacts with airborne chemicals and traps them before they can enter the cabin. The fibers in the filter media may also be electro statically charged so they will attract and hold dirt and contaminants more efficiently

Q: Which vehicles have cabin air filters?

A: Cabin air filters were introduced back in the mid-1980?s in Audis and other European luxury vehicles. The first domestic applications date back to 1994 (Ford Contour and Mercury Mystique). Today, cabin air filters are found in almost 80 percent of all new vehicles.

The best way to determine if a customer?s vehicle has a cabin air filter is to check your filters supplier?s catalog or database, or to look in the vehicles owner?s manual. Check the index for Cabin Air Filter, or look in the section that list scheduled maintenance items.

Q: Where is the cabin air filter located?

A: Most cabin air filters are located in the HVAC plenum assembly behind the glove box, or at the HVAC inlet near the cowl area at the base of the windshield in the engine compartment. Refer to the owner?s manual for the exact location of the filter and replacement procedure. On some applications, two filters are used in a stacked arrangement. This allows for easier filter replacement in tight quarters.

Filter replacement typically takes 10 minutes or less on the easier applications. But on others, it takes longer depending on how mush disassembly is required (the glove box or console may have to be removed to reach the filter). As a rule, no special tools are needed but care must be used to make sure the filter is positioned correctly and seals are tightly against its closure.

Q: How often should a cabin air filter be changed?

A: A simple dust-only filter should last two to three years depending on operating conditions. More frequent filter changes may be required in dusty areas. Combination filters that also trap odors should be replaced yearly. Refer to the vehicle owner?s manual for specific service interval recommendations.

Q: How often should an oil filter be replaced?

A: Every time the oil is changed, which for many vehicle is still every 3,000 miles or 3 to six months, whichever comes first.

The oil filter protects the engine?s bearings and other internal parts from dirt, metal wear particles and other contaminates that enter the crankcase. All modern engines use a ?full flow? filtration system that filters all of the oil after it passes through the oil pump. If the filter becomes clogged, a bypass valve will open and allow unfiltered oil to flow to the bearings. This can be very damaging if the oil is dirty.

When looking up a replacement oil filter for a customer, follow the filter applications in your data base or catalog carefully. The hole in the bottom of a spin-on filter must be the same diameter as the original and have the same type of threads (SAE or metric). If the hole size or threads are different, the filter may not fit properly, leak or damage the mounting. The gasket must also be in the same location to seal against the engine. If the diameter of the gasket is too large or too small, the filter may leak.

Filter access can be difficult on many late model engines, so your customer may need a special filter wrench to make a job easier. Filters should be tightened a half to three quarters of a turn after the gasket makes contact with the surface. If the filter is too loose, it may leak. If the filter is over-tightened, it may damage the seal or mounting threads and be difficult to remove the next time the oil is changed.

Used filters should be drained before disposal, and the oil should be collected and saved for recycling.

Q: How many cars and trucks have halfshafts and CV joints?

A: Around 80 percent of all late-model passenger cars are equipped with front-wheel drive (FWD) and have CV joints and halfshafts. About the same percentage of minivans also have FWD. Trucks and SUV?s by comparison, have either rear wheel drive (RWD) or four wheel drive (4WD). Many of those that have 4WD use halfshafts for the front axels, while many smaller SUV?s and crossover vehicles use halfshafts front and rear.

The CV shaft replacement market is estimated to be around ten million shafts a rear. According to Babcox Research, 92 percent of our installer readers service CV Joints and shafts, and do an average of 8.3 jobs per month.

Q: What is the leading cause of CV joint failure?

A: CV Joint problems are generally caused by boot failures. The rubber or hard plastic boot around a CV joint is there to keep dirt and water out, and to keep the joint?s vital supply of special grease inside. A loose, cracked, ripped or punctured boot is bad news because it will leak grease and allow outside contaminates to enter the joint. If a leaky boot isn?t discovered and replaced almost immediately, joint failure will usually follow within a few thousand miles.

CV joints also wear out as the miles add up. Wear increases tolerances inside the joint which can lead to noise and vibration. The outer joints usually experience more wear than the inner joints because of steering angels they experience. The boots on the outer joints undergo more flexing and are more exposed to road hazards than the inner boots.

A classic symptom of a bad outer CV joint is a clicking or popping sound that is heard when turning. A clunk or vibration that is heard or felt when accelerating or changing speeds, on the other hand, usually indicates a bad inner CV joint.

If a CV joint on a high mileage vehicle has failed, chances are its twin on the opposite side is nearing the end of its service life, too. You should recommend replacing both joints or halfshafts assemblies, not just the one that has failed.

Q: Which is easier to replace, a CV joint or the complete halfshaft?

A: Most technicians prefer to replace the complete halfshaft as an assembly rather than to change individual joints if either joint has failed. Replacing a CV joint requires removing the halfshaft from the vehicle. That?s 90 percent of the labor, so most technicians find it easier and faster to simply pull the old shaft and install a new one. Replacing the CV Joints on the ends of the shaft is a messy and time consuming job. Time is money and most installers would rather swap shafts and get the job done rather than spend an extra 30 minutes or more removing, cleaning, inspecting and replacing the individual joints.

Q: How many oxygen sensors are on today?s engine?

A: It depends on the model year and type of engine. On most four and straight 6-cylinder engines, there is usually a single oxygen sensor mounted in the exhaust manifold. On V6, V8 and V10 engines, there are usually two oxygen sensors, one in each exhaust manifold. This allows the computer to monitor the air/fuel mixture from each bank of cylinders. When displayed on a scan tool, the right and left oxygen sensor are typically labeled ?Bank 1, Sensor 1 and Bank 2 Sensor 1.

On later-model vehicles with OBD II (some 1993 and ?94 models, and all 1995-and-newer models), one or two additional oxygen sensors are also mounted in or behind the catalytic converter to monitor converter efficiency. These are referred to as the ?downstream? O2 sensors, and there will be one for each converter if the has dual exhaust with separate converters.

On a tool scan, the downstream sensor on a four or straight six cylinder engine with single exhaust is typically labeled ?Bank 1, Sensor 2.? On a V6, V8 or V10 engine, the downstream O2 sensor would be labeled ?Bank 1 or Bank 2, sensor 2.? If a V6, V8 or V10 engine has dual exhaust with dual converters, the downstream O2 sensor would be labeled ?Bank 1, Sensor 2? and Bank 2, Sensor 2.? Or the downstream oxygen sensor might be labeled Bank 1, Sensor 3 if the engine has two upstream oxygen sensors in the exhaust manifold (some do it more accurately monitor emissions).

It?s important to know how the O2 sensors are identified because a diagnostic trouble code that indicates a faulty O2 sensor requires that sensor to be replaced. Bank 1 is usually the front bank of cylinder on a transverse mounted V6 engine. But on a longitudinal V6, V8 or V10 it could be either the right or left bank. It may therefore be necessary to refer to the vehicle service literature to determine how the cylinder banks and oxygen sensors are labeled.

Q: How does a downstream O2 sensor monitor converter efficiency?

A: A downstream O2 sensor in or behind the catalytic converter works exactly the same as an ?upstream? O2 sensor in the exhaust manifold. The sensor produces a voltage that changes when the amount of unburned oxygen in the exhaust changes. If the O2 sensor is a traditional zirconia type sensor, the voltage output drops to about 0.2 volts when the fuel mixture is lean (more oxygen in the exhaust). When the fuel mixture is rich (less oxygen in the exhaust), the sensor?s output jumps up to a high of about0.9 volts. The high or low voltage signal tells the PCM the fuel mixture is rich or lean.

On some newer vehicles, a new type of ?wideband? oxygen sensor is used. Instead of producing a high or low-voltage signal, the signal changes in direct proportion to the amount of oxygen in the in the exhaust. This provides a more precise measurement for better fuel control. These sensors are also called ?air/fuel ratio sensors? because they tell the PCM the exact air /fuel ratio, not just a rich or lean indication like a conventional O2 Sensor.

The OBD II systems monitors converter efficiency by comparing the upstream and downstream oxygen sensor signals. If the converter is doing its job and is reducing the pollutants in the exhaust, the downstream oxygen sensor should show little activity (few lean-to-rich transitions, which are also called ?crosscounts? ). The sensor?s voltage reading should also be fairly steady (not changing up or down), and average 0.45 volts or higher.

If the signal from the downstream oxygen sensor starts to mirror that from upstream oxygen sensor(s), it means converter efficiency has dropped off and the converter isn?t cleaning up the pollutants in the exhaust. The threshold for setting a diagnostic trouble code (DTC) and turning on the Malfunction Indicator Lamp (MIL) is when emissions are estimated to exceed federal limits by 1.5 times.

If converter efficiency had declined to the point where the vehicle may be exceeding the pollution limit, the PCM will turn on the Malfunction Indicator Lamp (MIL) and set a diagnostic trouble code. At that point, additional diagnosis may be needed to confirm the failing converter. If the upstream and downstream O2 sensors are functioning properly and show a drop off in converter efficiency, the converter must be replaced to restore emissions compliance. The vehicle will not pass an OBD II emissions test if there are any converter codes in the PCM.

Q: What?s the difference between a ?heated? and ?unheated? oxygen sensor?

A: Heated oxygen sensors have an internal heater circuit that brings the sensor up to operating temperature more quickly than an unheated sensor. An oxygen sensor must be hot (about 600 to 650 degrees) before it will generate a voltage signal. The hot exhaust from the engine will provide enough heat to bring an O2 sensor up to operating temperature, but it may take several minutes depending on ambient temperature, engine load and speed. During this time, the fuel feedback control system remains in ?open loop? and does not use the O2 sensor signal to adjust the fuel mixture. This typically results in a rich fuel mixture, wasted fuel and higher emissions.

By adding an internal heater circuit to the oxygen sensor, voltage can be routed through the heater as soon as the engine starts to warm up the sensor. The heater element is a resistor that glows red hot when current passes through it. The heater will bring the sensor up to operating temperature within 20 to 60 seconds depending on the sensor, and also keep the oxygen sensor hot even when the engine is idling for a long period of time.

Heated O2 sensors typically have two, three or four wires (the extra wires are for the heater circuit). Note: Replacement O2 sensor must have the same number of wires as the original, and have the same internal resistance.

The OBD II system also monitors the heater circuit and will set a trouble code if the heater circuit inside the O2 sensor is defective. The heater is part of the sensor and cannot be replaced separately, so if the heater circuit is open or shorted and the problem is not in the external wiring or sensor connector, the O2 sensor must be replaced.

Q: What causes alternators to fail?

A: The main cause is usually overheating caused by overloading the charging system. The higher the load on the alternator, the higher it?s operating temperature. If the unit gets too hot, the rectifier diodes or soldered connections on the brushes or armature windings may be damaged.

Alternators are designed to maintain battery charge, not recharge dead batteries. For this reason, batteries should always be recharged with a battery charger if they have run down. New batteries should also be charged before they are installed. This will reduce the load on the alternator and reduce the risk of overheating and failure.

An alternator?s maximum output capacity should equal or exceed the maximum load created by the vehicle?s electrical system; this includes the voltage needs of the ignition system, fuel system, lights, A/C, radio and other power accessories. Alternator output is proportional to speed, so to achieve maximum output the engine has to be running at 2,000 to 2,500 RPM or higher to keep up with high electrical loads. Sitting and idling for a long period of time (especially during hot weather) with the A/C, lights and radio on may overtax the alternator and cause it to overheat and fail.

Q: How does a power-assisted steering rack work?

A: A power-assisted rack reduces the effort required to steer the wheels. A power rack is nothing more than a manual rack with a hydraulic chamber and some valves. High-pressure fluid from the power steering pump enters the rack and is routed through ?spool valves? connected to the steering column. When the driver turns the steering wheel, the spool valves open ports that direct pressure to the hydraulic chamber. A piston on the rack bar divides the chamber into two halves, and pressure is channeled into one side or the other depending on which way the diver is turning. This provides power assist and helps push the rack bar in the desired direction.

Normal operating pressures within a power rack generally do not exceed 150 PSI when the wheels are straight ahead. In a turn, however, pressure can climb to as much as 700 PSI or higher depending on how mush assist is needed.

Q: How can you tell if a rack is going bad?

A: Leaks are a sign of trouble, and so is increased steering effort especially when the vehicle is first started on a cold morning. If the seals around the spool valves inside the rack are leaking, the steering may feel stiff or sluggish. ?Morning sickness? tends to be more common in racks with aluminum control valve housing than ones with cast iron control valve housing. The only cure for this kind of problem is to replace the rack with one that has a new or sleeved control housing.

Leaks at the rack end seals will allow fluid to escape from the pressure chamber into the protective end bellows that surround the tie rod sockets. If the bellows contain more than a few ounces of fluid, therefore, it?s a sigh the seals are leaking.

Play or looseness in the steering would be another symptom that might indicate a worn rack. Over time wear can occur between the gear teeth where the input pinion meshes with the rack. Wear is usually greatest when the wheels are straight ahead. Most racks have a pinion preload adjustment. But if the adjustment is made with the rack in the centered straight ahead position, it may cause the rack to bind when the steering is turned to either side. The only cure for center wear is to replace the rack.

Other possible causes of steering play include worn tie rod ends, a worn steering input shaft coupling, loose rack mounts and worn wheel bearings. These items should also be inspected along with the steering rack.

Q: What happens if a timing chain or belt fails?

A: The engine stops running. If the cam drive fails, the camshaft stops turning, the valves stop opening, and the engine stops breathing. The engine will stop and will not run because it has no compression.

A timing belt or chain failure can cause expensive damage in ?interference? engines that don?t have enough clearance to prevent the valves from hitting the pistons if the cam stops turning or jumps out of time. Interference engines include most Acura, Honda, Hyundai, Infiniti, Isuzu, Nissan and Porsche engines, also some Audi, BMW, Mazda, Mitsubishi and VW engines, as well as Chevrolet 1.5L and 3.4L, 1995 and newer Chrysler 2.0L and 2.5L, 1997 and newer Chrysler 3.2Land 3.5L, and Ford Probe 2.0L and 2.2L engines.

A timing chain or belt may also jump time if it is loose. The engine may continue to run but will experience a loss of performance because of the altered valve timing.

Q: Why are plug wires so important for good performance, fuel economy and emissions?

A: The plug wires or ignition cables carry high-voltage current from the ignition coil(s) to the spark plug. If the plug wires have too much internal resistance or the insulation is leaking, not enough current may reach the plugs causing the plugs to misfire. This can cause hard starting, a rough idle, a loss of power, a big increase in hydrocarbon emissions and poor fuel economy.

On 1995-and-newer vehicles with onboard diagnostics II (OBD II), ignition misfires caused by bad plug wires can set a misfire diagnostic trouble code (DTC) and turn on the malfunction indicator lamp (MIL). In areas where vehicles must undergo emissions testing, this kind of problem will cause the vehicle to fail the emissions test.

Plug wires should be inspected if any of the systems are present, and when the spark plugs are changed. If wires show any obvious damage such as burned or cracked insulation, chaffing, loose plug boot or terminals, the wires should be replaced. Also, if visible arcing is present new wires are needed. Wires should also be replaced is there resistance measured end to end with an ohmmeter exceeds OEM specifications.

As a rule, if more than one plug wire has excessive resistance or the insulation is cracking, the entire wire set should be replaced

Q: What is the best method for replacing a set of plug wires?

A: Replace the entire set one wire at a time. Start with the longest wire and end with the shortest. Changing one wire at a time will reduce the risk of mixing up the firing order. The plug wires must be installed correctly so ignition timing will be correct. The wiring should also re rout the same as the originals to avoid ?crossfire? problems. Crossfire may occur when wires are positioned parallel to each other. The magnetic field that surrounds a wire when currents pass through it may induce current in an adjacent wire, unless the wires are separated by sufficient distance or crisscross to prevent this from happening. Also wires must be supported by looms or clips and positioned so they do not touch hot exhaust manifolds or rub against sharp edges.

Q: Please explain the method or policy for shipping of international orders?

A: With daily access to 25 million dollars in inventory, we can ship 95% of all orders within 1 day from our New Jersey location to anywhere in the world! Metric system can be used for calculating weights and dimensions Our location is in Manalapan, New Jersey (Zip 07726) is halfway between New York City, Philadelphia and Atlantic City Our experience shipping internationally covers 15 years. Method of payment is bank wire transfer (preferred) or major credit card Not only do we ship internationally, we do have brick and mortar locations (unlike some on line auto parts company’s that use drop shippers) All products are packed, wrapped and weighed by our own employees. Our breakage rate is 99.9%!! We ship overseas utilizing either Fedex, DHL, U.S. Postal Service or Schenker/Bax Global (freight-forwarder located in New Jersey) complies with all U.S export control laws and laws of final destination country.