Speed Density Systems Performance Reliability For Modern Engines
Modern engine technology is changing our concept of how we increase engine torque and fuel economy.
Temperature & Electrical Diagnostics
Engine coolant temperature is often a primary component of the “enable criteria” needed to run diagnostic monitors and store diagnostic trouble codes and related freeze-frame data.
Ball Joints, Bushings & Alignment – Steering Systems Under Stress
A variance in either the toe angle or Ackerman angle caused by worn ball joints and tie rod ends can turn a laser-precision steering system into a non laser-precision driving experience.
Servicing A Gasoline Direct Injection System
Because gasoline direct injection (GDI) was widely introduced during the 1990s, the configuration of any GDI system will vary according to age and application.
Drum Brake Service: Single-Anchor, Floating Shoe Designs
Although four-wheel disc brakes currently dominate the import brake service market, millions of drum brakes are serviced each day in independent import shops.
Modern Fuel Control Diagnostics: Sorting Through The Data Stream Maze
Adapted from Gary Gom’s article in ImportCar. When confronted with a fuel control problem on a modern vehicle, I’ll normally use short- and long-term fuel trims to determine if the problem is caused by one of many failures, such as a vacuum leak or a leaking fuel pressure regulator. If you’re like me, you’ll
Diagnosing Flood-Damaged Vehicles
While minor flooding at intersections often doesn’t cause many problems other than rusted brakes, major flooding can damage most of the mechanical and electrical components found in the engine and passenger compartments.
Subaru Pulse-Width Modulated Fuel Pumps
Many technicians aren’t familiar with PWM fuel pumps because they’re generally very reliable. But now that many import vehicles equipped with PWM fuel pumps are rolling up the miles, it’s time to turn the page from diagnosing two-line and single-line mechanically pressure-regulated fuel pumps to diagnosing electronically controlled PWM fuel pumps.
The Case Of The Missing Starter – A Diagnostic Dilemma
A client who owns a heavy-duty diesel shop called me to help diagnose a no-cranking condition on his father-in-law’s 2006 Chevrolet Tahoe.
Reading Tire Wear Patterns
Modern tire construction has generally trended toward low aspect ratio tire casings with more flexible sidewalls and rigid treads. Although this type of construction has made tires less sensitive to negative camber angles used in many current steering geometry designs, many types of tire wear patterns continue to indicate problems in a vehicle’s steering geometry.
Parasitic Drain: Jeep Grand Cherokee
As a general rule, a “parasitic drain” of less than 30 milliamps (mA) is normal for most vehicles 15 years old and newer. Keeping in mind that most manufacturers now publish parasitic drain values, let’s assume that a battery drain exceeding 50 mA is cause for concern.
When Over-Voltages Electrocute PCMs
During the past nine months, I’ve had three instances of powertrain control module (PCM) failures on Jeep Wrangler vehicles that were evidently caused by an over-voltage condition.
