• Coil output is determined by the mass of the iron core being converted into a magnetic field. Creating this magnetic field takes time, called the current ramp. Once the iron core is saturated, increasing the current flow does not add to that stored m
  • Problems in modern electrical systems can cause all sorts of complaints, from a taillight that doesn't work to an engine that runs poorly. But using voltage drop testing will help you diagnost these automotive problems.
  • It was not all that long ago that a slight random misfire might go undetected. Misfires generate unburned hydrocarbons and increase the load on the catalytic converter. If the misfire rate is excessive, the catalytic converter can overheat and be dam
  • Each time you face a vehicle in your bay this spring with a reported A/C problem, you'll initially check the airflow through the ducts and the A/C controls, maybe static pressure in the system. Once under the hood, you will look at the compressor to
  • You all already know how important it is for an ECM/PCM (or any other control module, for that matter) to have a good power supply and good grounds. Typically, grounds fail at their point of connection, and testing these ground connections can be mad
    Pete Meier
  • Even though the optical bus system isn’t being used in extremely high volumes it’s still worth understanding how the system works, what goes wrong, and how to fix it properly.
  • The military employs some very talented pilots. The best of these pilots are sent to special schools where they learn the techniques of air-to-air combat. It is the variety of techniques they learn that separates them from the rest. Honing your diagn
  • You may have studied circuits, but you should troubleshoot current paths. Circuits get complicated, and when you troubleshoot current paths, you simplify the complicated.
  • While the basic idea behind the alternator hasn't changed much since it replaced the direct current (DC) generator in the early 1960s, it has evolved to meet new demands. Computer-control is the norm and has impacted charging system diagnostics as te
  • Ignition systems can be one of three basic designs: the distributor ignition system, the distributorless (DIS) ignition system or the coil-on-plug (COP) system. They all perform the same function, but even in the individual systems, design difference
  • Back in November of 2010, Motor Trend magazine named the Chevrolet Volt the "Car of the Year." Making its debut at the same time was the Nissan Leaf, and I believe 2010 will go down in automotive history as the first year mainstream manufacturers off
  • In the early world of automotive ?black box? technology NASA gave us in the 1970s, parallel interface was the only show in town. What that means is that every sensor and actuator had to be hard-wired to the brain box and other than dashboard-mounted
  • During the last 10 years, I?ve worked in a variety of shops and, to date, have been the only tech that owned a DSO. When techs see it in use for the first time, they invariably ask what I?m doing and why ? and then ask if they should own a scope of t
  • Wheel speed sensors detect the rotation speed of a wheel that's moving. Active wheel speed sensors detect rotation speed all the way down to zero, and the newest sensors can detect the direction of rotation, too. Four different sensor designs are in
  • Want to know a secret? Electronically controlled transmissions on newer vehicles actually are similar to their electronically controlled engines, and often are just as easy to diagnose.
    Figure 1
  • This fine piece of Detroit engineering arrived at the shop on a tow strap, dead in the water. The battery voltage is very low, due to the owner cranking the engine trying to get it started.
  • As the weather warms, more and more of your customers will be switching over their HVAC control settings to Max A/C. And if the system doesn't respond by blowing that refreshing cool air, they will show up at your door to find out why.
  • There was a time that hybrid cars were unusual enough that people would turn their heads and point them out to their friends as one passed by. Those were the days when folks were undecided as to whether this hybrid idea was even going to stick. Of co
  • From the days when automobiles were first built, racing has played an integral role in their development. Racing has been where new technologies are tested and proven on their way to becoming mainstream. It also has been where many ideas are introduc
  • Not too long ago, one of our Motor Age community members wrote excitedly about a new technology he was told about in a training class. The topic of his excitement was ion sensing ignition systems, and I certainly admire him for his enthusiasm. But as