Diagnostic Dilemmas: Playing the Diagnostic Shell Game
More often than not, deciphering diagnostic trouble codes is like playing a high-tech version of the old circus sideshow “shell” game. In the trouble code shell game, we are led to believe that the pea (diagnostic solution) is hidden under one of the shells (DTCs) stored in the diagnostic memory. Unfortunately for the diagnostic technician,
The Fuel Injector Market and System Configurations
Looking back into automotive history, it’s hard to believe that carburetors were still being installed on import vehicles as late as 1989! But carburetors require all sorts of external vacuum and electronic gimmickry to control the cold-starting, fast idle, hot idle and low-speed cruise functions. Electronic fuel injection has since replaced carburetors in all import
Carburetor Repairs & Recalibrations
As a follow-up to “Dusting Off Fuel System Fossils” in April’s edition of Underhood Service, I will share many driveability concerns and emissions failures that I’ve repaired by rebuilding, and sometimes modifying, certain carb circuits. But before diving into a carburetor rebuild or recalibration, be certain that you understand the system you’re working on, including
Confronting the Complete Cooling System Service
By now, it’s obvious to most service shops that cooling system service is an absolute “must-do” on any nameplate. Once a cooling system suffers long-term neglect, it turns into an ongoing source of problems for the owner and his service technician because, when corrosion starts to take place, the effects can’t be reversed. For that
Diagnostic Dilemmas: Driving Forces Behind a Driveability Technician
He used to be known as the tune-up guy, the shop troubleshooter or the ace mechanic. Today, he’s known as a driveability tech. Tomorrow, when body control electronics come on full line, he’ll probably be known as an electronics diagnostics technician. Whatever his name might be, most of us know that driveability techs are smart,
Selling Multi-Coil Ignition Parts
Time has indeed passed you by if you still believe in the traditional import engine tuneup. Many years ago, much of the import service market revolved around the annual spark plug, ignition cable, distributor cap and rotor replacement needed to maintain an import engine at peak efficiency. During the past decade, however, multi-coil waste-spark and
OBD II Diagnostics:Tips And Tricks to Make the Process Easier
The Malfunction Indicator Lamp (MIL) can be a golden light of opportunity for your shop. If the light comes on, it means the Onboard Diagnostics II system (OBD II) has detected an emissions-related problem. OBD II is designed to turn on the MIL if a problem occurs that may cause emissions to exceed federal limits
Mass Air Flow Operation Strategy
When diagnosing hot-wire air flow meters (A/F meters) on Subarus and similarly equipped Asian vehicles, technicians may find that, while the meter passes all recommended test procedures, the engine exhibits driveability conditions associated with lean air/fuel mixture ratios. In these cases, it’s best to form a diagnostic strategy based on the relatively simple operating principles
Understanding Operating Strategies
As driveability technicians, we’ve been taught to solve diagnostic problems by gathering and analyzing data. Data usually comes in three basic forms, the first of which is sensory data that we can see, hear, smell or feel. The second form is measured values gathered by using test equipment like lab scopes and multimeters. The third
Head Gasket Replacement
During some point in their service lives, most import engines built with cast-iron cylinder blocks and aluminum cylinder heads will need a cylinder head gasket replacement. The vulnerability of aluminum-head engines to head gasket failure is caused by the aluminum cylinder head expanding approximately 1.5 times more than the cast-iron block. Although measured in thousandths