September 2008 Archives

A heat shield is often used to protect a starter solenoid from high engine compartment temperatures. When installing a replacement starter, it may come with a heat shield or it may require transferring the heat shield from the failed starter.

If the original starter uses a heat shield, it's important to install the proper one on the replacement starter using the correct fasteners. Most heat shields clip or bolt to the starter. Certain styles of heat shields installed on GM vehicles use an M4x0.7x10.0 thread forming bolt. (Fig. 13, A) If this bolt is misplaced during service, it should be replaced with the same bolt, part number 10201205, available at any GM dealer.

Fig. 13

- Thanks to Mike DeSander

With TIS 2 Web, independent service centers have access to a variety of GM programming applications and software instantly available from a central website. No longer is it necessary to wait for a CD to arrive at the service center to have the latest programming updates.

TIS 2 Web is a new version of the GM Techline Information System (TIS) that includes a suite of diagnostic/programming applications, including Service Programming Systems (SPS) for GM vehicles (required to reprogram GM vehicle control modules), Tech 2 scan tool software download, and the Tech 2 View and Tech 2 Snap Shot diagnostic applications.

TIS 2 Web offers increased speed of updates, consistent software versions for all users, improved maintenance and support, and use with generic SAE J2534 devices.

TIS 2 Web Subscriptions

TIS 2 Web is available via an on-line subscription. Go to www.acdelcotechconnect.com and click on the TIS 2 Web logo under GM Service Information. Service centers can select from several annual subscription choices.

TIS 2 Web - All Access

(GM, Saturn and Saab) $1,395

This option for Tech 2 users includes:

Tech 2 Diagnostic Software

Tech 2 View

Tech 2 Snap Shot

Service Programming Software

TIS 2 Web - Service Programming

(GM, Saturn and Saab) $995

This option for use with J2534 devices includes:

Service Programming Software

TIS 2 Web - All Access

(Saab only) $750

This option for Tech 2 users includes:

Tech 2 Diagnostic Software

Tech 2 View

Tech 2 Snap Shot

Service Programming Software

TIS 2 Web - Tech 2 Diagnostics

(GM, Saturn, Saab) $750

This option for Tech 2 software only includes:

Tech 2 Diagnostic Soft ware

Visit www.acdelcotechconnect.com for complete details about the TIS 2 Web application, including subscription information as well as computer hardware and software recommendations.

- Thanks to John Putnam and Bob Stewart

The following technical tips provide repair information about specific conditions on a variety of vehicles. If you have a tough or unusual service repair, the TSS Technical Assistance Hot Line can help. Call 1-800-825-5886, prompt #2, to speak with a technical expert with the latest OEM information.

Clutch Bleeding Problems

Ford Ranger with non-self adjusting clutch sets

The non-self adjusting clutch sets may exhibit a problem of poor or no release of the clutch. The problem is caused by air trapped in the hydraulic system -- specifically the master cylinder.

In order to isolate and correct the condition, first eliminate the possibility of any worn or damaged components in the release system. With the clutch installed and the transmission in the vehicle, check to make sure there is no leakage from the master cylinder and around the fittings of the Concentric Slave Cylinder (CSC). Then, in order to determine if air is trapped in the master cylinder, disconnect the line going into the CSC and push down on the clutch pedal. The pedal should be stiff. Theoretically, if the master cylinder portion of the system is completely full of hydraulic fluid and has no trapped air, the pedal will not move at all (or very little - less than 1/2"). The reason this simple test works is due to the nature of the connector between the master and slave cylinder. When it is not connected to the slave cylinder the valve in the line stays closed and will not allow any hydraulic fluid to escape. 

During operation in the vehicle, the connections of the master cylinder are pointing down and the piston rests at the high end and is pushed down for the release stroke. This creates an air trap at the piston end away from the connector lines where fluid comes in and goes out. 

The illustration (Fig. 11) of the system as installed in the vehicle: 

A.) Location of trapped air

B.) Location of retaining clip

C.) Notice angle of master cylinder

D.) Bleeder valve

E.) Line connector

F.) Internal slave

Fig. 11

When the master cylinder is removed from the vehicle (Fig. 12) and manipulated so the lines are pointing up and the piston end points down (with the reservoir cap removed), the piston can be compressed into the slave cylinder and air bubbles will be seen escaping from the top of the reservoir if air is present. Once all the air is purged out of the master cylinder, it can be reinstalled on the vehicle. Before connecting the hard line to the CSC, push the pedal by hand to confirm it is solid.

Fig. 12

An alternative that can be tried before bench bleeding the master cylinder as described above is to raise the front of the vehicle to reduce the downward angle of the master cylinder and make it as level as possible and then bleed the system by repeating the following several times as needed:

Depress the clutch pedal fully

Loosen the bleeder screw on the CSC to allow air (and some fluid) to escape

Retighten bleeder screw

Release pedal

Power Steering Performance Concerns

2003-2006 Cadillac Escalade, Escalade ESV, Escalade EXT; 2003-2006 Chevrolet Avalanche, Suburban, Tahoe; 2003-2007 Chevrolet Silverado Classic; 2007-2008 Chevrolet Silverado, Suburban (2500 Series only); 2003-2006 GMC Yukon, Yukon Denali, Yukon XL; 2003-2007 GMC Sierra Classic; 2007-2008 GMC Sierra, Yukon XL (2500 Series only)

A lack of steering assist may occur when stopped or during parking maneuvers. This condition may go away or greatly improve once the vehicle begins to move or is above parking lot speeds. It may be aggravated by worn tires, low tire air pressure, low power steering pump pressures, and tires larger than stock size.

In all cases, it is recommended to use the proper tire size and that the maximum tire pressure is set according to the manufacturer's specification, especially for the front tires.

To repair this condition, perform the power steering system test found in the appropriate Service Information. Make any necessary repairs based on system diagnosis.

If diagnostics do not lead to any repair, this concern is a normal operating characteristic.

If the vehicle is equipped with a 670 gear box, it may be replaced with a 680 gear box. To determine if the vehicle is equipped with a 670 gear box, inspect the mounting bolts that attach the stub shaft housing. A 670 gear box will have only three mounting bolts. If replacing a 670 gear box with a 680 gear box, it will be necessary to replace the:

Power steering gear (GM part number 88965542)

Union fitting (GM part number 26025709)

Both inlet O-ring seals (GM part number 26001594)

The TSS Q&A provides answers to common questions received by the ACDelco Customer Support Center.

Q: Are TSS shops eligible for the GM New Vehicle Supplier Discount?

A: Yes. TSS service center owners and employees are eligible for the GM supplier discount on most new 2007, 2008 and 2009 GM vehicles at participating GM dealerships (eligibility may change at any time without notice and some models may have limited availability). So far this year, TSS shops have purchased more than 500 GM vehicles using the supplier discount.

Vehicles may be taken from dealer stock or ordered. In addition, the GM supplier discount can be combined with most other regional incentives for even greater savings. Savings using the supplier discount varies depending on model. (Fig. 10)

Fig. 10

Q: A GM New Vehicle Supplier Discount authorization number is needed to receive the discount. How do I get this?

A: Follow these steps to get a supplier discount personal authorization number:

Go to www.acdelcotechconnect.com

Click on the Total Service Support tab and then the GM Vehicle Supplier Discount link on the right side of the page. (You will have to log in by entering your 6-digit TSS code (it begins with a 6) and your zip code.)

On the GM Vehicle Supplier Discount page, click on the link at the bottom of the page to access the GM supplier discount website. It's important to always access the GM supplier discount website through acdelcotechconnect.com. This loads the website with the correct company code for TSS shops.

If you have used this website before, input your user name and password that you have used in the past. If you do not have a user name and password, click on New to Supplier Discount to register on the site.

Click "yes" when you are asked, "Are you a TSS/ACDelco account?" This question will only appear if you have logged in using a previous user name and password.

If you are asked if you would like to use this new account number because it has changed, always respond "yes." This is part of a recent change to improve the process.

Begin by selecting GM Supplier Discount on the left side of the page. Next, you are required to input your birth date, zip code, and other vehicle purchase information.

Once you have completed the process, print out your personal authorization number and bring it to your local participating GM dealer for your GM supplier discount.

Q: How many times in a year can I use the supplier discount?

A: TSS service center owners and employees are eligible to receive two supplier discount authorization numbers per year.

Q: How can I get more information about the GM New Vehicle Supplier Discount?

A: For additional information about the GM supplier discount or if you have questions about the authorization number process, call 1-800-960-3375. When calling, please state that your company name is TSS/ACDelco, not your individual service center name.

If you have any questions about the TSS program or any current ACDelco activities, contact the Customer Support Center at 1-800-825-5886, prompt 0.

ACDelco stands behind every product it sells -- all makes, all models.

When you, as a TSS shop, use ACDelco parts, the parts as well as the labor are warranted for 12 months or 12,000 miles, whichever comes first. It's the peace of mind that comes with the ACDelco Consumer Assurance Program.

After you have made repairs using ACDelco products, hand out a Consumer Assurance Program brochure to your customers. It provides all the details about the program works and how customer satisfaction is the top goal of your service center and ACDelco.

Updated posters (Fig. 9) and consumer brochures are available through the ACDelco E-Store.

Fig. 9

All TSS service centers are automatically enrolled in the Consumer Assurance Program. For complete details about the program, visit www.acdelcotechconnect.com. Here are some highlights:

If any installed ACDelco product fails within the 12-month/12,000-mile warranty period, the repair will be made at no additional cost for parts and labor.

If necessary, towing is covered.

If the failure occurs within 25 miles of the original repair facility, customers should return to that facility for ACDelco warranty coverage.

If the failure occurs more than 25 miles from the original repair facility, customers should call 1-800-ACDelco, prompt #3, for directions to the nearest TSS-participating service center for the repair.

Customers will need to provide their original sales receipt for authorization of the repairs.

- Thanks to John Putnam

Fuel contamination is the main cause of electric fuel pump failure. Dirty fuel, water, rust, scale and fuel tank sediment all work to clog the pickup strainer or inlet filter as well as cause internal pump damage. (Fig. 7) The result is premature pump failure. 

Fig. 7

When replacing a failed fuel pump, check the following to avoid future problems and a repeat failure:

Fuel contamination

Fuel tank degradation

Fuel line corrosion or damage

Blocked inlet strainer

Pump Diagnosis

Before condemning a fuel pump, the first step in fuel pump diagnosis is to perform a fuel pressure check. If the fuel pressure and volume are within specification, use a scan tool to check for diagnostic trouble codes.

If the fuel pressure check reveals improper fuel delivery, too-high or too-low pressure or insufficient flow, there could be a number of possible causes. These include a clogged inlet filter, damaged fuel pump, electrical faults, faulty fuel pressure regulator or fuel line restrictions.

In addition, inspect the terminal in the wiring harness connector and in the connector on the pump module. Any damage to the connectors may result in voltage drop across the module and may lead to a repeat failure.

Checking the Fuel

Once the fuel pump has been diagnosed as the cause of the customer concern, checking the fuel can identify any harmful additives, dirty fuel, or excessive water that could cause pump failure. (Fig. 8) If the inlet filter/strainer is clogging up, the pump's current draw may increase, which could quickly wipe out pump brushes with excess arcing and heat.

Fig. 8

When excessive fuel contamination is evident, remove and thoroughly clean the tank. Tank cleaning procedures vary among models, but general guidelines include: 

Disconnect the negative battery cable.

Relieve the fuel system pressure.

Drain the fuel tank and remove it from the vehicle.

Use oil-free compressed air to blow out fuel lines if needed.

Remove the fuel-sender assembly and inspect for damage.

Fill the fuel tank with hot water. Do this more than once, if necessary.

Pour the flushing water out of the tank through the fuel sender opening.

Ensure that all water is completely removed from the tank before reinstalling.

After cleaning the tank, the fuel and water mixture should be handled as hazardous waste material according to local, state and federal regulations.

Replace the Strainer

The fuel pump inlet strainer filters the fuel to help protect the fuel pump. It's essential that it be replaced and installed correctly when replacing the fuel pump.

On gerotor-type pumps, if the strainer is improperly installed, the gears can scuff and drag, causing noise and vibration. Without a properly functioning strainer, turbine-type pumps will quickly seize up. 

In addition to the strainer, the fuel system can be blocked by a crimp or dent in the fuel line. Any blockage can cause premature fuel pump failure. Also check fuel lines that appear sound externally but may have internal corrosion. Disconnect and inspect any suspect lines.

Fuel pumps do eventually wear out. But sometimes there are other factors that lead to fuel pump failure. It's important to perform a complete diagnosis of the fuel system in order to avoid a replacement pump failing as well. 

- Thanks to Dennis Kissack

"Why do I need to know Ohm's Law?" was probably a common question in high school physics class. And the teacher's common response was, "Because it's on the test." Fast forward to today and it seems like everything in the automotive service business is related in some significant way to physics, such as stoichiometric air fuel ratios, fuel pressure, hybrid powertrains, braking systems and mass airflow sensors.

For those of you who were (or are still) scared of physics, Bosch Diagnostics has teamed up with Midtronics, the industry leader in battery technology, to create a state-of the-art charging system analyzer that is robust and easy to use. Today's networked vehicles depend on consistent voltage, amperage and noise-free signals to operate. More than ever, proper charging system health is crucial to vehicle electronic control units (ECUs) functioning correctly. The BAT151 (Fig. 5) is a comprehensive tool that covers starting, charging, battery condition, voltage drop and a whole host of other electrical-system tests to quickly pinpoint the problem. The multi-language, easy-to-follow menus enable technicians to quickly isolate and repair electrical system problems using the automated testing sequences. Complex repairs will benefit from the individual testing selections that provide specific component-level testing with minimal hookup.

Fig. 5

At the heart of the BAT151 is Midtronics patented Dynamic Conductance technology, which combines direct temperature measurement and battery cell health checks. Advanced preventative maintenance algorithms help identify batteries that not only have failed, but also flag those that are nearing end-of-life. Optional amp clamp and test leads transform the BAT151 into a complete, portable system analyzer. Cable voltage drop tests are preconfigured for battery, starter and alternator, as well as the ability to create user-specific tests. Quick parasitic drain analysis and full multi-meter functions eliminate the need for a separate DVOM.

The BAT151 utilizes flash memory and is field updateable via USB connection. In addition, a user-supplied SD card can store test files, which can be viewed on a Windows PC in Internet Explorer® and transferred to a customer RO. An optional integrated printer provides an immediate customer printout, including easy-to interpret line and bar graphs. (Fig. 6)

Fig. 6

ACDelco TSS shops qualify for a special rebate on the BAT151. Visit www.acdelcotechconnect.com for details and pricing.

- Thanks to Bob Augustine

With the winter driving season approaching, many drivers might be wondering if the battery in their vehicle will continue to provide them with reliable service or leave them stranded on a cold, snowy night. Although there is no sure fire way to predict when a battery will ultimately fail, there are some steps that can be taken to help ensure reliable service. 

The first step is a simple visual inspection of the battery to make sure the terminal connections are clean and free of corrosion and that there are no signs of damage or leaks. It is also important to ensure that the battery tray is free of debris and the battery hold-down is secure.

The second step is an inspection of the vehicle's electrical system. The following items should be checked:

Determine the battery's state of charge and state of health by testing the battery with a conductance-type tester or subjecting it to a physical load test.

Check the output of the alternator. Proper output is necessary to operate the vehicle's electrical demands and to maintain the battery's charge.

Check the cranking motor for proper operation and electrical draw.

Check all cables within the electrical system for excessive voltage drops.

Determine if the battery is properly sized (Cold Cranking Amps and Reserve Capacity) for the vehicle.

Battery Storage

There are many questions about how to properly store and charge a battery. (Fig. 4) During storage, a slow chemical reaction takes place inside the battery that causes it to lose charge over time. This is referred to as self-discharge.

Fig. 4

The rate of self-discharge varies directly with the temperature in which the battery is stored. To reduce the rate of self-discharge, batteries should be stored in a cool place. If in storage for extended periods of time, charging with a constant voltage, variable current taper rate charger is recommended when the open circuit voltage of the batteries drops below 12.3V. "Trickle charging" should not be used to keep batteries in a charged condition when in storage.

If batteries are going to be stored in an area that will subject them to freezing, they should be fully charged before being placed in storage. A fully charged ACDelco battery has a freezing point of -60 degrees F or lower.

There are no issues with storing an ACDelco battery on concrete. ACDelco battery cases are made of polypropylene, which will not allow current drain to the concrete. Many early style batteries used hard rubber cases that were somewhat porous and had a high carbon content, which would allow the battery to discharge if placed on concrete.

Customer Questions

Here are a couple of questions customers may ask regarding the health of their batteries.

Q - Is summer or winter harder on a battery?

A - The summer heat is much more detrimental to batteries. Heat speeds up the chemistry that occurs within the battery and can accelerate conditions such as grid growth, grid corrosion, and plate shed, which may ultimately lead to battery failure.

Q - I accidentally left my headlights on and now my battery is "dead." Should I replace it?

A - A battery that has become discharged can usually be recharged and placed back into service.

- Thanks to Mike DeSander and Dennis Kissack

Traditionally, diesel fuel has been refined from crude oil, and is referred to as petroleum-based (or petro) diesel. It is now possible to manufacture diesel fuel from biological (plant and animal) materials. This fuel is referred to as biodiesel. Biodiesel fuel is blended with petrodiesel fuel (typically 5% bio and 95% petro), and the result is referred to as a blended fuel. Because the characteristics of petroleum diesel and biodiesel fuels are different, questions may arise about the use of biodiesel fuels. Here are some typical questions and answers.

Are all 5% biodiesel fuels the same? 

GM currently supports the use of up to 5% blend of biodiesel (B5) in all its diesel vehicles.

GM does not distinguish between the types of feedstocks (different vegetable oils and animal fats) used to make biodiesel. However, biodiesels are not all the same. Biodiesels and subsequent blends made from different feedstock will have different cloud points (see below). In addition, some variations in cloud point can be expected due to processing differences.

Inconsistent blend compositions might result based on blending methods (example, splash blending) and temperature of blending (it is recommended that biodiesel be kept at least 10°F (6° C) above its cloud point during blending). Cloud point will increase with increasing amounts of biodiesel in blends.

Feedstock Cloud Point

Soy approx.    32°F (0°C)

Beef-tallow approx. 53°F (12°C)

How much does ambient temperature affect biodiesel's ability to flow in a suction-only fuel delivery system?

Ambient temperature affects the fuel's tendency to gel and its ability to flow. As the fuel is cooled, its ability to keep the wax dissolved decreases, and eventually, a temperature is reached when the wax precipitates from the fuel. The temperature when the fuel first becomes cloudy due to wax precipitation is called the cloud point. As the fuel is cooled further, more wax precipitates from the fuel. At about 10°F (6° C) below the cloud point, the fuel becomes so thick that it cannot flow. This temperature is called the pour point or gel point.

A 5% biodiesel will raise the cloud point of the fuel about 4 to 5 degrees F (2 to 3 degrees C). A 20% biodiesel will raise the cloud point 5 to 10 degrees F (3 to 6 degrees C). Because fuel passes through the fuel filter before it reaches the suction side of the pump, the expectation is that this type of system would be susceptible to filter plugging due to wax or precipitates.

When using 5% biodiesel, are there negative performance or durability considerations?

ASTM International (originally known as the American Society for Testing and Materials) is the organization that defines the desired quality of biodiesel for vehicular use in the US.

If the biodiesel meets the ASTM standard, there are no durability concerns at the 5% level. However, if the original biodiesel does not meet the ASTM specification, even with 5% there is potential for negative effects. For example, biodiesels high in glycerin, a byproduct formed when vegetable oil is processed to make biodiesel, and unreacted vegetable oil content (>0.24 mass %) can result in gelling at higher temperatures, causing filter plugging, and can also cause long term injector damage.

5% biodiesel can cause negative effects if the fuel in the tank deteriorates to form insoluble (plastic-like) constituents and corrosive products.

Biodiesel fuel has a higher tendency to foul and oxidize compared with petroleum diesel fuel. Performance at cold temperatures will be somewhat worse because biodiesel naturally has a higher cloud point than diesel fuel.

Biodiesel can act as a solvent, loosening sludge in the bottom of the tank that may cause premature filter plugging.

What happens if the customer increases the percentage? 10-20% is apparently available on the street.

An increase in percentage will raise the cloud point of the fuel. It can also cause compatibility issues with elastomeric (rubber-like) constituents. And if the base biodiesel is out of spec then it will worsen the problems caused by bad biodiesel.

At present, pump labeling of blending percentages at filling stations is an individual state issue. There is no Federal mandate to label biodiesel pumps.

- Thanks to Shailesh Lopes and Andrew Buczynsky

Since fuel economy is the topic everyone is talking about these days, it's fitting to pass along some good news as well as bad news in regard to vehicle fuels and fuel efficiency.

Let's start with the good news, and that means increases in fuel economy and advances in alternative fuels.

FUEL ADVANCES

There are plenty of choices for consumers who want to get more miles out of a gallon of gas. For the 2008 model year, 17 GM models -- more than any other automaker -- achieve EPA highway fuel economy of 30 miles per gallon or higher. (Fig. 1) Efforts to expand on those numbers focus on a variety of new technology in different applications that increase efficiency while reducing emissions.

Fig. 1

Direct Injection

The application of direct injection technology to an engine contributes to an increase in horsepower, an improvement in fuel consumption, as well as a reduction in cold-start hydrocarbon emissions.

With direct injection, precisely metered fuel is delivered directly to the combustion chamber, which has a cooling effect in the chamber. Cooling the incoming air charge enables a higher compression ratio, which also improves engine efficiency. Less fuel is required to produce the equivalent horsepower of a conventional port injection combustion system.

The combustion process of conventional fuel injected engines uses air and fuel that partially evaporates in the intake port or intake manifold prior to being introduced into the combustion chamber. Direct injection is a continuation of the evolutionary process of moving the fuel introduction point closer to the cylinder to improve control.

The fuel injectors are located beneath the intake ports. (Fig. 2) The intake ports only transfer air, unlike port fuel injection, which flows air and fuel, thus increasing efficiency.

Fig. 2

Clean Diesel

All heavy-duty diesel engines manufactured in the U.S. must meet new emissions regulations that were instituted January 1, 2007 that require a reduction of nitrogen oxide (NOx) and hydrocarbons (HC). One way to meet these regulations is with the use of a Diesel Particulate Filter (DPF), which is an after-treatment technology that reduces particulate matter.

The DPF works by trapping diesel particulate matter in a honeycomb-like ceramic "brick" after it travels through an oxidizing catalyst. Remaining exhaust gases are routed out through the exhaust system. To ensure optimal performance, the system must undergo periodic "regeneration" to eliminate accumulated soot from the filter. The regeneration process uses heat to burn off the soot and, in most cases, is performed automatically.

An onboard computer controls fuel injection and oxygen content to adjust the exhaust energy to the appropriate level to clean the particulate trap. Periodic servicing of the filter is required.

2-Mode Hybrid

The GM 2-Mode Hybrid system uses two sources of power: an internal combustion engine and a hybrid transmission consisting of two electric motors and a nickel metal hydride battery pack.

When the vehicle accelerates from a stop, the battery-powered electric motors can move the vehicle alone or, depending on the amount of power requested, assist the engine. The engine provides the power to maintain speed once the vehicle is under way. In addition, the vehicle's regenerative braking captures energy normally lost as brake heat and returns it to the vehicle's battery pack for reuse.

GM introduced the 2-Mode Hybrid system on transit buses in 2003. For the current fleet on the road today, it's estimated that more than 730,500 gallons of fuel are saved annually and certain emissions are reduced by up to 90 percent.

DRIVING TIPS

In addition to the latest technology, there are several things all drivers can do to increase their fuel economy immediately regardless of what they drive.

Slow Down, Drive Smoothly - Avoid quick/full throttle acceleration from a standstill and high cruising speeds. While the optimum MPG for highway cruising speed varies from vehicle to vehicle, faster is almost always worse.

Empty the Trunk - Carrying unnecessary items in the trunk takes power, and that means more gasoline consumption and reduced performance.

Avoid Extended Idling - There is no need to idle the engine until it reaches operating temperature. Idling wastes fuel.

Combine Trips - A vehicle uses much more fuel when the engine is cold, especially in winter when the engine takes the longest to warm up. Combine trips so that the vehicle needs to warm up only once.

FUEL FACTS

Here's where the bad news comes in -- usually in the form of neglected vehicle maintenance or even worse, home-made fuel economy elixirs. The best advice for maximizing fuel economy is to use a high quality fuel of the recommended octane and to perform regular maintenance.

Top Tier Fuels - Some fuel manufacturers provide gasoline advertised as Top Tier Detergent Gasoline. These fuels help to keep fuel injectors and intake valves free of deposits. Clean engines provide optimal fuel economy, performance and reduced emissions. When Top Tier fuels are not available, use ACDelco Fuel System Treatment Plus (p/n 10-3003, 20 ounce bottle; p/n 10-3004, 12 ounce bottle) at oil change time to remove intake system and injector deposits.

Do not confuse Top Tier fuels with higher octane fuel (plus/premium grade). Plus/premium fuels are required in some high performance vehicles; however, they do not necessarily represent the higher detergency present in Top Tier Detergent Gasoline. 

For additional information about Top Tier fuels and availability, visit www.toptiergas.com.

Recommended Grade (Octane) Fuel - Purchasing higher than required octane fuel is a waste of money. Using higher octane fuels in a vehicle that requires regular unleaded fuel will neither increase performance nor improve gas mileage

High performance engines that do require premium fuel (91 octane or higher), MUST use fuel of at least this octane. Use of lower octane fuel may result in reduced performance, knocking, and/or permanent engine damage.

Tire Pressure - A major contributor to poor fuel economy is under-inflated tires, which create drag that the vehicle's powertrain must overcome. Keeping tires inflated to the proper pressure as shown on the vehicle's tire and loading information label not only serves to increase gas mileage but cuts down on tire wear, further decreasing cost per mile.

Air Filter - The engine can't efficiently draw air through a dirty air filter, which wastes fuel. Check the Service Information for the recommended service intervals for a particular model.

Engine Oil - Always use the proper viscosity, starburst-rated oil, described in the Owner's Manual. Oil that has a higher than required viscosity will create more drag on the internal components of the engine, causing more work for it, especially when cold.

FUEL MYTHS

Fuel Economy Improvement Products - Various unproven products to improve vehicle fuel economy have been reported, ranging from magnets that align molecules to chemical combustion improvers.

The U.S. Federal Trade Commission summarizes results for products tested by the federal government at www.ftc.gov/bcp/edu/pubs/consumer/autos/aut10.shtm. The majority did not work, and for those that showed some effect, the benefit was too small to be cost effective.

Blending Other Fuels into Gasoline - Do not attempt to blend kerosene or diesel fuel into gasoline to improve mileage. This may result in inconsistent performance and permanent damage to the vehicle. (Fig. 3) Both kerosene and diesel fuel are distillate fuels not meant for use in spark ignition engines. They have very low octane and, because they have greater density than gasoline, they will cause heavy engine deposits and degradation of engine oil.

Fig. 3

Blending Chemical Solvents Into Gasoline - Do not attempt to blend solvents such as acetone, ketones, and methanol into gasoline. These solvents can be incompatible with the vehicle's rubber or sealing components. In the case of methanol, corrosion of metal parts in the fuel system also may occur.

- Thanks to Dennis Kissack and Mike DeSander