AUGUST 2006 VOLUME 31, NO. 1. Magic Machines Performance Products Selling the Right Friction. Reprint Edition

Transcription

1 VOLUME 31, NO. 1 AUGUST 2006 B R A K E. E X H A U S T. C H A S S I S Making Sense of Sensors Magic Machines Performance Products Selling the Right Friction Reprint Edition

2 By Jim Wilder Undercar Digest Editor An estimated 90% of all emissions-inspection failures are the result of bad oxygen sensors. Part of the reason for those failures is that not all oxygen sensors are created equal and it s getting harder and harder to tell them apart. That s why it s important for shop operators and technicians to know that the oxygen sensors they install are from a manufacturer whose entire program is structured around OEM information and consists of only OEM product. Mike Weaver, owner/president of Walker Products, and his staff are on a campaign to educate technicians on the differences between specific styles of O2 sensors: OEM-based or direct-fit oxygen sensors, universal, non-oem manufactured and some including offshore units that are appearing on parts shelves. The company also is seeking additional high-quality distributors throughout the country. Technicians who have been in the industry for a number of years are familiar with the Walker Products name because they ve been using the company s carburetor and fuel-injection repair kits. Founded in 1946, Walker Products has evolved into a state-of-the-art manufacturer of a variety of automotive parts with an expertise in sensors aircharge temperature sensors, camshaft and crankshaft position sensors, EGR valve-position sensors, EGR valve-pressure sensors, engine coolant-temperature sensors, manifold absolutepressure sensors, mass Walker Products has been able to successfully design 657 part numbers to replace 4,526 OEM numbers. (From left) Steve Knox, sales manager; Mike Weaver, owner/president; and Tom Hollman, sales director, recognize the importance of accurate and well-organized cataloging in providing quality product and services to their customers. The Walker Products team consists of 12 senior managers with an average of 25 years of experience each, all sensitive to their customers needs. air-flow sensors, throttle-position sensors and oxygen sensors. With headquarters in Los Angeles, Walker Products has ISO- 9001/QS-9000 certified manufacturing facilities in California, Colorado and Missouri. Compliance with the new ISO/TS standard is expected soon. The company, which introduced its first line of oxygen sensors in 1995, is also an original-equipment service (OES) supplier of oxygen sensors to vehicle manufacturers for their parts and service business. The company also sells its oxygen sensors under various private labels including the Walker brand. By carefully researching and product testing, Walker Products has been able to successfully design 657 part numbers to replace 4,526 OEM numbers. These applications provide 98% coverage of the passenger cars and light trucks through 2006, said Andrew Golike, director of OES sales. This makes Walker Products the highest-returning-investment O2-sensor line in the market. Walker Products is always the first to provide the latest model coverage to our customers. It even offers oxygen sensors for Dodge Sprinter diesel-powered delivery trucks. Additional part numbers for diesel-powered vehicles are expected to be released after the new emission standards for diesels go into effect for model year 2007, said Jim Waddell, O2-sensor product manager. This will be a great opportunity to get into the growing diesel-applications market. Mike Wolfe, director of

3 Grant Kitching, vice president and general manager of Walker Products, notes that it s important for shop operators and technicians to know that the oxygen sensors they install are from a manufacturer whose entire program is structured around OEM product. engineering, calls the oxygen sensor the mostcritical sensor on the automobile today. It s basically giving information back to the computer on the vehicle, related to how good a job it s doing of adding the right amount of fuel to the air the engine is ingesting, Wolfe said. That s its primary purpose and function. If it s failing, it can have a major impact on fuel mileage and it can contribute to shortening the life of the catalytic converter significantly. Oxygen-sensor technology has changed dramatically in the past 20 years and, like other automotive technologies, has forced technicians to stay on top of the learning curve to provide professional service, said Paul Kikuchi, Walker Products engineering manager. He noted that in the mid- 70s the first oxygen sensors were unheated. The thimble-shaped unit sat in the exhaust stream and used the exhaust gases to heat it to operating temperature. Then the manufacturers started to put electric heaters inside the sensors to get them to operating temperature faster. On-Board Diagnostics II (OBD-II) also required oxygen sensors downstream of the converter, he said. In recent years, because of even tighter emissions regulations, the industry has gone to fast-light-off, ultra-fast-light-off and planar oxygen-sensor technologies these sensors light off in as little as five seconds. More and more cars now are going to linear sensors, also known as air/fuel-ratio sensors, Kikuchi said. That allows the engine to be controlled at a wider range of air/fuel ratios. These sensors allow engines to run lean at certain engine operations or rich for times when you need hard acceleration or are under a heavy load. You see more and more linear sensors in gasoline engines because they allow for better performance and gas mileage from the same system. When checking sensors, technicians using a scan (Back to front) Mike Wolfe, director of engineering, and Paul Kikuchi, engineering manager, monitor O2-sensor functional results in vehicle testing. tool monitor fuel trim to determine whether a sensor is working properly. If the fuel trim is at a high percentage above or below zero it indicates a malfunctioning sensor. The ideal value that you want is centered around zero, known as stoichiometric or perfect balance, Kikuchi said. As long as the values are in low percentages somewhere around plus or minus 12%, the sensor is probably working properly. If you have one of your engine exhaust manifolds running at its limit of around 20% consistently that s probably an indication that you need to replace the sensor. Many of the later-model sensors are being designed so they are supposed to last 100,000 miles, Wolfe said. However, that is not always the case. If a vehicle has 60,000 to 80,000 miles and the owner has seen a decline in fuel mileage, even though there isn t a check-engine light or an MIL light illuminated, it s probably not a bad idea to consider that as an option to replace the oxygen sensor, because it could be contributing to or causing this loss in fuel mileage. Counter mats and other point-of-purchase materials can help shop operators explain to customers why oxygen sensors should be replaced. Some of the earlier vehicles equipped with oxygen sensors actually had a dash light that came on, not to say the sensor was bad but as a recommended service-replacement interval for sensors, Kikuchi said. I ve looked at data from aged sensors from practically every sensor supplier, he said. I have seen there is a drop in performance as you get beyond 50,000 miles. When you get that drop-off,

4 the sensor is running slower. It s running at different voltage levels. It s not enough to trigger the diagnostics in the vehicle, but it is controlling the engine differently than when it was new. One of the biggest challenges for technicians today is parts proliferation in oxygen sensors, says Grant Kitching, vice president and general manager of Walker Products. Within the four-wire types alone, you have fastlight-off, ultra-fast-light-off, air/fuel-ratio sensors, Oxygen sensors should be installed using a specialized socket and a torque wrench. That is one of the advantages of using an OEMbased oxygen-sensor program such as ours, Kitching said. That way you are using our expertise to determine the proper sensors for the proper applications. The days of buying one-, two-, three- and four-wire universal sensors are long gone. It s very important because of the different types of heaters and shields. You have to have a variety of differentbased sensors to make up a complete program, such as ours. And that brings to light a problem in which some technicians already are learning the hard way, Kitching said. It doesn t pay to save a few dollars by Steve Knox, sales manager, poses with a parts cabinet that Walker Products offers shops to keep popular applications in stock for quick response to customer needs. low-watt density, high-watt density and planar. Many technicians have learned the hard way that although two oxygen sensors may look identical on the outside, the components inside can be radically different, Wolfe said. On some Toyota applications, if you don t actually refer to the emissions decal on the vehicle to determine what system it has on it, you can get yourself into trouble, he said. Also, if you don t read the OEM number off the sensor when you remove it in order to select the correct replacement part, you will run into issues. You ll have three sensors that look identical and internally the technologies are different. One will be what we call a standard four-wire heated sensor, one of them can be a fast-light-off oxygen sensor and the other one can be an air/fuel-ratio sensor. They actually have the same connectors on them and the parts look identical. It s very prudent for technicians to be very cautious of that particular instance. And that does cross just about everybody s platform to some degree whether it be Toyota, Chrysler, General Motors or Honda, whoever. Those technologies are not interchangeable and they can, in fact, potentially damage the circuits in the ECU because of excessive current through the heater circuit. Rachel Golike uses a press and extensive tooling applications at Walker s manufacturing facility to consistently crimp seals and terminals to O2-sensor wires, meeting strict strength and conductivity specifications. August

5 Pablo Lopez uses sensitive and automated pull-test equipment to verify and statistical process control (SPC) to chart the crimp strength at setup settings of the terminal press. installing universal sensors and/or the lower-cost sensors that are coming in from offshore. Due to the fact that there is such a proliferation of sensor technology today our preference is that our customers purchase a direct-fit sensor. Although we offer universal sensors, our preference would be that Things to watch Replacing an 02 sensor damaged from antifreeze poisoning (left) will not fix the coolant-leak problem, and the life of the new sensor will be severely reduced. Removing the guides from the connector (center) to mate to the vehicle wiring harness will not create a functional part. Wiring locations and heater characteristics will not be the same as for the part removed, and you may short the ECU as well. Not necessarily the result of a defective O2 sensor, the damage at right may be caused by an air leak in the exhaust system causing the sensor to respond as a lean condition and driving the controls rich. they install a direct-fit part. What we have seen is that the offshore manufacturers are sticking with the four basic styles of sensors: one-, two-, three- and four-wire sensors, Kitching said. We have seen, because of the functional characteristics of those sensors, that frequently they can cause the system to run richer than normal, and that will usually shorten the life of the catalytic converter too, even though a code isn t set, Wolfe said. All of the offshore sensors we have tested indicate they would probably cause major issues shortly down the road. In other words, they would have a very short life if they didn t set a code as soon as they were installed. The probability of their damaging a very expensive catalytic converter because of the way they function is high as well. Butch Becker, general manager of the Colorado manufacturing facility, said Walker Products has gone to great lengths to provide detailed parts information to technicians, including the locations of sensors being replaced. It also shows where to find calibration-code interchange information for Fords in the model years. The catalog is a must for professional installers, he said. To simplify the understanding for the technician, we have detailed illustrations in our catalog for each part number, Waddell said. It includes the specific connector design and lead lengths. The locations of sensors will soon to be added in greater detail on our Web site and CDs to further help the technician. Some of the 12-cylinder and 10-cylinder vehicles on the market today have up to eight oxygen sensors installed on them. They have split exhaust manifolds, so they have four catalytic converters on the vehicle, and there is a sensor behind and in front of each catalytic converter. Clinics conducted by Walker Products cover the basics of the different types of sensors and how they operate, including the use of sockets designed specifically for oxygen sensors and the proper torque specifications; how dropping a sensor can damage it; how certain additives and other contaminants can damage units; and, of course, diagnostic techniques. We believe these clinics are a very important tool due to the complexity and nature of these sensors and also the vehicles in which they are installed, Wolfe said. The feedback we ve gotten from the technical clinics has been very positive and well received. The technicians really agreed with the need to understand how all these sensor technologies work in order to make a conscientious diagnosis of what might be wrong with the part and replacing it with the correct sensor. O2-sensor service is a great opportunity to increase your business, and Walker Products has the best O2 program to make you successful. UD Walker Products Inc S. San Pedro St. Los Angeles, CA Fax:

6