Diagnostic Solutions: How Electric Power Steering Systems Are Changing Undercar Service
Electric power steering contains a steering wheel position sensor and a steering input torque sensor. The data from these two sensors report to an EPS module, which translates the steering input torque into an appropriate level of steering assist via a pulse-modulated, bi-directional electric motor that’s connected to the steer gear input shaft or integrated into the steering rack assembly. The steering position sensor should read “zero” when the vehicle is traveling straight ahead.
Diagnostic Solutions: Using The ‘Systems’ Approach To Starting Problems
Good examples of systems logic occur each September when I serve as a technical advisor for a church-sponsored single mom’s car care clinic. We sometimes, for example, accidentally bump hidden cranking “disable” switches installed by suspicious ex-husbands or encounter engines with bad fuel pumps that will start only by spraying a liberal dose of starting fluid into the air intake.
Diagnostic Solutions: AGM Batteries And Testing
Two of the greatest changes we’ve seen in starting/charging systems during the past few model years have been the expanded use of the Absorbed Glass Mat (AGM) battery as standard equipment and the accelerating pricing structures of both AGM and conventional flooded-cell batteries.
Diagnostic Solutions: Direct Fuel Injection Systems
For veteran technicians, it’s no wonder that the internal combustion engine (ICE) has been pronounced “dead” on more than one occasion. After having gone through the gas turbine craze during the early 1960s and the rotary engine fad of the 1970s, it comes as no surprise that we’re witnessing still another resurrection of the reciprocating internal combustion engine in the form of gasoline direct fuel injection.
Diagnostic Solutions: Modern Spark Plug Diagnostics, The ‘Art And Science’ Of Reading Plugs
With the advent of electronic engine management systems, “reading” spark plugs has become something of a lost art. In the days of mechanical carburetors and distributors, the color and texture of the spark plug’s insulator could provide important information about the air/fuel ratio, spark timing and cylinder condition.
Diagnostic Solutions: Nissan Pathfinder Wouldn’t Crank
Recently, an old customer called to tell me his 1988 Nissan Pathfinder “fishing wagon” wouldn’t crank. The Pathfinder’s battery was less than one year old and passed a preliminary conductance test with flying colors. The Pathfinder’s starter activation system is typical for many import vehicles of this vintage. In the manual transmission version, the ignition switch supplies power to the clutch switch relay windings when in the crank position.
Diagnostic Solutions: Variable Camshaft Timing And Back Pressure Issues
When the topic of variable valve timing (VVT) comes up in import repair shops, few realize that the concept of increasing low- and high-speed engine torque by automatically advancing and retarding valve timing isn’t a recent development. For example, I recently discovered an old variable camshaft timing gear that I bought during the 1960s featuring a torsion spring device that retards valve timing in response to the increased rotating torque needed to turn the camshaft at higher engine speeds.
Diagnostic Solutions: Engine Coolant Temperature Sensors
Considering that roughly 1,500 or more different vehicle models are introduced into our domestic market each year, it’s becoming more difficult to predict how a Powertrain Control Module (PCM) will utilize data from a particular sensor or detect an out-of-range sensor in any single vehicle platform. The engine coolant temperature (ECT) sensor provides a good illustration of how many on-board diagnostic strategies have changed.
Diagnostic Solutions: Extended Oil Change Intervals
Extended oil change intervals are a mixed blessing. On the upside, extended oil change intervals are conserving precious oil and reducing carbon emissions. On the downside, many vehicle owners are forgetting to check their engine’s oil level between oil changes. The most common result is an engine ruined by excess accumulations of varnish and sludge due to using motor oils that are not approved by the engine manufacturer.
Diagnostic Solutions: Contaminated Fuel Can Wreck Havoc On Fuel Delivery Systems
Import Specialist Contributor Gary Goms discusses how contaminated fuel can mimic the symptoms produced by defective fuel pumps, fuel injectors and fuel control components like mass air flow (MAF) sensors. Although cases involving contaminated gasoline are relatively rare nowadays, they still occur. In many cases, the technician has replaced the fuel pump or MAF sensor to address a P0171/P0174 “lean-condition” DTC with no result.