We continue our investigation of engine knock sensors with a look at one and two-wire sensors.

In the previous issue of Counter Point, we discussed the various causes of engine knock. Prior to the age of electronic engine control, an engine designer had a limited number of effective tools to guard against engine knock. Principle among these were combustion chamber design, the octane of the fuel used and mapping of the spark advance curve. The designer couldn’t risk the possibility of engine damage caused by knock, so it was always necessary to keep the engine well short of the point where it might begin. This assured engine longevity, but hurt performance.

Part 2: Analyzing Amperage Results When Testing Ignition Coils with a Low Amp ProbeCheck out Part 2 of Barry Gersten’s Current Ramping series. This time, he covers how to analyze […]

John Thornton discusses a case study about a high milage 1997 Chrysler Concorde with rough idle issues. The vehicle has no codes and the coil, plugs and wires have all been recently replaced. John goes into great detail on how he went about diagnosing the problem by using scan data and waveform analysis.

Dave Hobbs presents an interesting case study of a Chevy Malibu exhibiting battery discharge issues, no start problems and with a B1516 BCM code. Dave discusses the associated TSB and smart charging system components related to this issue.

Engine knock limits performance and can cause permanent damage. This time, we’ll look at its causes.

Under certain conditions, combustion in a spark ignition engine can degrade into an abnormal preignition process that causes a “knocking” or “pinging” sound. This undesirable combustion process limits the engine’s output and specific efficiency levels. It occurs when the fresh air/fuel mixture preignites in spontaneous combustion before being reached by the expanding flame front.

Part 1: Getting Started – How to shop for a well designed Low Amp Clamp. In order to choose the best Low Amp Clamp it is important to know the limitations of the various Low Amp Clamps. Any limitations are usually revealed in the Manufacturer’s Spec Sheet Data.

A number of emissions programs are conducting an emissions test on OBD II vehicles that has been nicknamed a “plug and play” test. Perhaps something similar to this has already happened to you. A customer brings his vehicle to your shop because the malfunction indicator lamp (MIL) is glowing on the dashboard. After retrieving the stored diagnostic trouble codes (DTCs) and freeze frame data, then conducting a thorough diagnosis, you determine the cause of the fault. The defective part is replaced, the DTCs and freeze frame data are cleared from the Powertrain Control Module (PCM) memory and the vehicle is taken for a road test. After the road test, the PCM’s memory is rechecked for stored or pending DTCs. None are found.

Oil is killing our cars!” warns Keith Ansell, President of Foreign Parts Positively. “Be aware that ‘New and Improved,’ or even the ‘standard products’ we have been using for many years, are destroying our cars. It isn’t the same stuff we were getting even a year ago.”

Although a bit of a sensationalist, Keith is not completely out of line and he isn’t the only Internet auto expert touting the effects of the industry required ZDDP (zinc dialkyl dithiophosphate) decrease in motor oil.

By Gary Goms. When we’re attempting to diagnose a charging system failure, it helps to think of the battery’s state of charge (SOC) as a type of checking account. If […]

Using scope patterns, Jim Wilson discusses and demonstrates a procedure for diagnosing EGR related misfire issues by examining scope patterns of the different cylinders.

If you’ve spent hours struggling to master a new computer software system, you can well understand how a modern auto technician might feel when confronted with not just one, but hundreds of different software configurations built into the platforms of the 17 different vehicle manufacturers now being sold in our domestic market.

While new car recalls have been among the biggest news stories of the year, an analysis by Edmunds.com, assures consumers that despite these recent headlines, recalls were much more of a concern in decades past.

By Ken Shriner. Does ethanol usage reduce fuel economy compared to conventional gasoline? What vehicles can use ethanol-containing fuel? Can ethanol-containing fuel affect cold starting? Does it dry the fuel system? Can it cause engine deposits? Read on to find the answers to these questions and more with BG Products, Inc.

If referrals are number one, then why do so few shop owners put much effort into getting more of them? Do you really want to know what your customers are […]

By Wayne Colonna. A scan tool can be an effective transmission diagnostic tool. But to understand what’s happening inside the trans, you must be able to properly interpret the raw sensor data the scanner provides.

A little while back I wrote an article concerning key numbers for auto service shops. The numbers covered at that time included total spending, total gross profit, potential work found per car, number of oil changes, number of new customers and tech vs. non-tech ratio. I was recently asked to cover some additional key numbers, so here we go!

In this training tip clip from the Complete Hybrid Training Program, Craig Van Batenburg talks about the battery backup for the brake by wire brake system and no start issues on the Toyota Prius. He touches on no start issues and concerns such as wrong or too much oils P309 High Voltage leak codes, corridor resolver connections and low battery pack issues.

Peter Orlando with the third of his ABS Tech Tip clips, this time with a hydraulic tip that you can use on any brake system. Peter gives us the breakdown on some tips for monitoring and controlling contaminate issues during a brake system service that can cause problems with the ABS system.

In this clip instructor Peter Orlando gives us some hands on instruction on resistance testing ABS solenoid assemblies. Peter gives several in depth tips tricks and gotchas related to resistance testing the isolation valves and working with the component schematics to perform the pin out testing

In this tech tip clip, Instructor Peter Orlando gives you a helpful tip concerning your new ABS wheel speed sensor. He explains to you how to use your voltmeter and a screwdriver to test if the new part is bad or good BEFORE you even put it in the car.

In this tip clip case study instructor Dave Hobbs presents the case study of a 2004 Malibu with a no start condition. Diagnostics later revealed a short in the radio causing the rest of the components on that bus to be unable to communicate. In this Tip Clip Dave gives some helpful info on diagnosing these types of interconnected problems.

By Dave Hobbs. No matter how complex ‘smart’ charging systems appear at first glance, it still comes down to a battery, an alternator and some modules monitoring and controlling voltage regulation. We’re sure you’ve got the smarts to handle that.

Tire Pressure Monitoring Systems are and have been a required feature on U.S. Passenger vehicles since 2008. Introducing this technology to the way we maintain our vehicles has improved safety and vehicle performance, increased fuel efficiency and tire life. It also has forever changed the way autos and tires are serviced. Any operation that works on tires has been faced with serious challenges to the way they do business. Thus is the nature of change. You can either run from it (lose business) or embrace it and seize the opportunity to grow and enhance your business.

By Scott “Gonzo” Weaver. Ever wonder how your cable TV comes into your home on that single coaxial cable? In simple terms… it’s like a CAN system. A good definition of a CAN system would be: High speed communication sent via data lines to and from components.

By Larry Carley. Diagnosis is often the biggest challenge, especially if the cause of a no-cooling problem is not obvious. Is it the refrigeration circuit, an electrical problem or a control issue?

From 1993 to 2008 the GM 4l60E transmission used a pressure switch manifold to tell the computer what gear was selected. In this Tip Clip instructor Wayne Colonna gives a detailed technical overview of this component with some helpful info on diagnosing associated problems.

Orange cables in hybrid vehicles means SAFETY SAFETY SAFETY. In this Tech Tip Clip instructor Dave Hobbs gives us instruction and insight on what to look for in safety equipment and multimeters for use in Hybrid applications. Remember techs, safety first when dealing with hybrid vehicles and high voltage.

Air-conditioning service stinks sometimes. Let’s face it. I mean it sometimes stinks literally – like bad odor stink. Those of us in the warmer and more humid climates regularly run into customers complaining of a foul odor that emanates from the dash. Your customer today is driving a 2003 Chevy Trailblazer and describes their complaint as this terrible musty odor. When you climb inside the vehicle to confirm the complaint, your nose causes the rest of you to want to do a 180, but you know it’s going to be your job to turn this foul odor into a profitable job. You are all too familiar with the cause and the fix.

According to the new refrigerant’s developers, there are chemical differences between HFO-1234yf and the current R-134a system. As a shop owner, you’ll need to learn the Safety, Equipment and Charging Issues surrounding this new refrigerant.

Data-bussing and multiplexing can be complex and aggravating. In this clip instructor Dave Hobbs teaches us simple and easy tricks for diagnosing data bus and module issues.

Gasoline direct injection has been gaining momentum in the industry for some time. BG recently published an article recognizing GDI, and the fact that it will be around for some time. Gasoline direct injection (GDI) was first used in 1925 on the Hesselman engine. Jonas Hesselman designed the engine to start on gasoline and then switch over to run on diesel or kerosene. But in 1952, Bosch developed the first automotive direct injection system that actually ran on gasoline. Mercedes Benz wasn’t far behind in 1955 with the first direct injection sports car, the 300SL.

Airtex offers the following Tech Tip to assist technicians in performing a fuel system voltage drop test. Misdiagnosis is the leading cause of fuel pump problems and returns. Often times a voltage drop test is the only effective way to find excessive resistance in high amperage circuits. It’s a quick and easy test that doesn’t require any dis assembly, and will give you immediate results on whether you’ve got a good connection or a bad one. Check out this tech tip from Airtex offering a step by step procedure to assist technicians in performing this valuable and easy test.

By Mitch Schneider. Intermittent automotive service problems are one of the few things capable of terrifying and paralyzing folks on both sides of the service counter.
Everyone is terrified of something. It’s a fact of life.
Probe deep enough, look hard enough and you will find a phobia that is if not paralyzing, then, at the least, debilitating.
If that fear isn’t enough to inhibit your ability to act, I’ll bet it is significant enough to ensure that at least some of your actions fall out of the realm of what most of us might consider “normal” — whatever normal means.

In this clip Jim Wilson teaches us about graphing MAP and RPM in your scan data to test for glitches in the pattern in order to isolate mechanical, fuel or ignition problems.