Exhaust Archives - Page 13 of 19 - UnderhoodService
Tenneco Introduces In-Depth Walker Converter Diagnostics and Strategies Workshop

Tenneco Inc. has introduced an intensive emission control diagnostics training workshop under the Walker exhaust brand that will reach automotive service professionals in close to 60 North American cities during 2011.

Troubleshooting Wideband O2 Sensors

Many late-model imports such as Honda, Toyota, Volkswagen and others use Air/Fuel sensors rather than conventional oxygen sensors to monitor the exhaust gases coming out of the engine. What’s the difference? An air/fuel sensor can read a much wider and leaner range of fuel mixtures than a conventional O2 sensor. That’s why they’re also called “wideband” O2 sensors.

Diagostic Dilemmas: Lost in ‘The Diagnostic Woods’

This real-world case study of a 2002 Chevy S-10 pickup, a 1995 Buick and a 1995 Lincoln Town Car illustrates why “chasing” trouble codes can get you lost in the Diagnostic Woods.

Tech Tip: Toyota MIL On with DTCs Set in Subfreezing Temperatures

Following a cold soak in subfreezing ambient temperatures, some 2003-’08 Corolla and Matrix vehicles equipped with a 1ZZ-FE engine may exhibit an MIL on with one or more of the following DTCs as the result of a vacuum leak at the intake manifold.

Pulling Codes: The Story of Code P0446

This is the first in a series of investigations covering many states’ top emissions-related codes. Our goal in this report is to discuss the characteristics of the P0446 code as it applies to many GM systems.

Tech Feature: Courage Under Misfire

Generally, when a customer brings a vehicle into a shop that has a misfire concern, they will describe it as bucking, jerking or loss of power. They also may describe it, depending on the cause, as a jerking when they take off from a start, but smoothes out once the vehicle gets moving. They may tell you the check engine light has been flashing.

Tech Tip: Follow These Steps Prior to Replacing Kia’s Catalytic Converter After Finding DTC P0422

Kia’s OBD II engine management systems use dual oxygen sensors, which among other things allow monitoring of the efficiency of the Manifold Catalytic Converter (MCC), also referred to as the “warmup” cat. Some technicians who retrieve DTC P0422 – Main Catalyst Efficiency Below Threshold (Bank 1) mistakenly replace the catalytic converter under the floor of the vehicle (possibly because the converter under the car has been referred to as the “main” catalyst). This leads to repeat repairs, unnecessary expense and customer dissatisfaction.

Tech Feature: Mazda6 and Mazda3 Driveability Diagnostics and Electronic Throttle Control

Drive-by-wire throttle control systems are pretty much trouble-free but have to be taken into consideration as you perform routine service and diagnose problems, and it changes the way you service these cars when it comes to cleaning the throttle plates, advises Bob Dowie, import specialist contributor, who also covers electronic throttle control’s tie in with ABS and VSC systems.

Catalytic Converters Stolen from Memphis Repair Shop

Thieves in Memphis, TN, cut through a fence and stole catalytic converters off at least nine vehicles at Classic European Motors. In addition, TVs, a stereo and even the tires and wheels were taken from the vehicles.

Crankshaft and Camshaft Position Sensor Diagnosis

Nothing is more frustrating than diagnosing an intermittent cranking, no-start complaint with no diagnostic trouble codes (DTCs) and no apparent failure pattern. Much of the time, the cranking, no-start complaint lies with a failing crankshaft or camshaft position sensor. Many of these failures can be heat-related and might require several warm-up cycles to duplicate.

Tech Feature: The Changing Face of Automatic Transmissions

Today’s computer systems have completely redefined automotive operation, particularly when it comes to transmission control.

Tech Feature: Oxygen Sensors are Key to Performance and Fuel Economy

Do you know your oxygen sensors? Oxygen sensors have been used for more than a quarter of a century, dating back to 1980 when the first computerized engine control systems appeared. The oxygen (O2) sensor is part of the fuel management system. It monitors unburned oxygen in the exhaust. The powertrain control module (PCM) uses this information to determine if the fuel mixture is rich (too much fuel) or lean (not enough fuel).