Emissions Archives - Page 23 of 24 - UnderhoodService
Diagnostic Solutions: Catalytic Converters

The design and function of catalytic converters has changed dramatically since their introduction in 1975. The first “two-way” catalytic converters were oxidizing-only designs that combined hydrocarbon (HC) and carbon monoxide (CO) with oxygen to form water vapor (H2O) and carbon dioxide (CO2). Oxidizing converters were originally manufactured in pellet bed or monolithic “honeycomb” styles. Currently,

Tech Feature: Performance Modifications…Getting a ‘Handle’ on Your Customers’ Tuning Needs

The sport compact car market is hotter than ever. The market has moved beyond the simple bolt-ons such as wheels, tires, brake rotors and spoilers. It’s not unusual today to see sport compact engines producing upward of 400 horsepower on the street. With so much power under the hood, the challenge is getting the horsepower

Troubleshooting MIL Issues: OBD II & “CAN” Scan Tool Diagnostics

The Malfunction Indicator Lamp (MIL) is one of the most misunderstood warning lights on vehicles today. Most motorists have no idea what the light means or why it’s on. Some think the MIL light is an oil change reminder light. Others realize something must be amiss to cause the light to come on, but don’t

Viewpoint: Cat Burglars and the Converter Cartel

How many catalytic converters can a battery-powered reciprocating saw cut from a dealer’s lot before the battery runs out? The answer is 18, according to news reports. In one night, 18 converters were removed at a Mentor, OH, Mitsubishi dealership. Other dealerships have been hit, with an average of 15 converters cut loose per night.

Buy or Bend?

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Diagnostic Solutions: Oxygen Sensor Diagnostics

Once considered leading-edge technology, today’s oxygen sensor has become a commonplace service item on modern vehicles. Popularly introduced in the 1970s, the Lambda or, as it’s more popularly known, the oxygen sensor, rapidly became standard equipment as it’s a vital component of closed-loop or feedback fuel control technology. By using a voltage input from the

Up in Vapor

Gasp! It’s the “Gas Cap Code”! Oh no, you just pulled a code P0422, evaporative purge small leak detected… Here goes the needle in the haystack syndrome. So what do you do? Recommend a new gas cap and ship it? Well you could do that, but would that be in your or your customer’s best

2006 Underhood Service Repair Market Industry Profile

Welcome to the 2006 Underhood Service Repair Market Industry Profile, our in-depth report of the independent automotive repair market. This profile highlights many of the elements of doing business in today’s repair shops. The information presented is a good indicator to make short-term predictions about these shops. It’s also a fair yardstick to see how

Diagnostic Dilemmas: The Pressures of Intake Manifold Vacuum Tests

Several years ago, a retired school teacher brought in a 1994 Chevrolet S-10 Blazer that had developed an intermittent rough idle condition. Although a rebuilt engine had been installed a year before, and all of the wiring and vacuum hoses looked as if they were in factory condition, I took nothing for granted. An ignition

Codes & Converters

It is a moral dilemma that many shops encounter on a regular basis. It starts when a good customer comes in with the engine light a blaze. Running your usual diagnostics, you encounter a catalytic converter efficiency code, slow to responded oxygen sensor or some proprietary fuel trim code. Other than the light, the customer

Diagnostic Solutions: Throttle Position Sensors

Although conventional throttle position sensors attached to the throttle shaft are considered basic technology on modern engine management systems, the conventional throttle sensor plays an important role in its relationship with other sensors. The voltage inputs of most throttle position (TP) sensors may, for example, be coordinated with the barometric pressure (BARO), manifold absolute pressure

Diagnostics Through CAN Networks

Since model year 2003, a growing number of domestic and import vehicles have been built with a new onboard communications protocol called CAN (Controller Area Network). CAN is essentially an engineering standard for how computers and modules talk to one another via the serial data bus in a vehicle’s wiring system. It’s a high speed