GMC/Chevy Light Truck: Central Port Fuel Injection Diagnosis
Back in 1992, General Motors introduced a new type of fuel injection system known as “Central Port Injection” (CPI), which GM also refers to as “Central Multi-point Fuel Injection” (CMFI). The system was used on 4.3L V6 Vortec engines through 1995, and was redesigned in 1996 and renamed “Central Sequential Fuel Injection” (CSFI). The system
Emissions Analyzers: What is Really Going On Inside that Engine?
An emissions analyzer is one of the most useful pieces of diagnostic equipment you can own. Scan tools are great for reading fault codes and sensor data, but a scan tool by itself can’t tell you what is actually going on inside the engine’s combustion chambers. A scan tool can read misfires and tell you
Diagnostic Solutions: Fuel System Pressure & Volume Checks
For maximum efficiency, modern import fuel injection systems require that fuel be delivered at a specified volume and pressure. Because the fuel injector’s job is to mix fuel with the intake air charge, it must produce a finely misted, conical spray pattern through the fuel injector nozzle. Lower-than-specified fuel pressures not only fail to provide
Diagnostic Dilemmas: Getting In-Sync with a Couple Wranglers
It’s axiomatic in the diagnostic trade that, as soon as one thinks he has command of a particular system, the gods of technology pitch a curve ball that unerringly slips under the swing of the diagnostic bat. Not that I’ve never seen a 4.0L Jeep engine before; I’ve serviced dozens, perhaps hundreds of them. The
Tech Talk: Positioning Yourself to Handle TP Service
Although conventional throttle position sensors attached to the throttle shaft are considered basic technology on modern engine management systems, the conventional throttle sensor plays an important role in its relationship with other sensors. The voltage inputs of most throttle position (TP) sensors may, for example, be coordinated with the barometric pressure (BARO), manifold absolute pressure
Buying an Import Scan Tool
Thinking about buying a new scan tool? Choosing a tool that provides the best coverage and the most diagnostic bang for your buck isn’t easy with so many different products to choose from today. There are simple code reader tools, entry-level “generic” scan tools, professional-grade tools with bi-directional communication and additional test capabilities, OEM scan
Diagnostic Solutions: Oxygen Sensor Diagnostics
Once considered leading-edge technology, today’s oxygen sensor has become a commonplace service item on modern vehicles. Popularly introduced in the 1970s, the Lambda or, as it’s more popularly known, the oxygen sensor, rapidly became standard equipment as it’s a vital component of closed-loop or feedback fuel control technology. By using a voltage input from the
Battery Charging: All Charged Up!
A battery charger is something every shop should own, and most do. But battery technology has changed in recent years. Battery chargers that were designed for older conventional lead acid batteries (called “flooded” cell batteries because the cells are filled with liquid electrolyte) may not be the best choice for newer batteries with absorbent glass
Tech Tip: Diagnosing Ignition Misfires
A flashing Check Engine light and a P0301 to P0312 diagnostic trouble code is a sure-fire indication that one or more cylinders are misfiring. Occasional misfires may pass unnoticed, but a steady misfire is hard to miss. The engine usually feels rough, lacks power and uses more gas than usual.
Diagnostic Solutions: Throttle Position Sensors
Although conventional throttle position sensors attached to the throttle shaft are considered basic technology on modern engine management systems, the conventional throttle sensor plays an important role in its relationship with other sensors. The voltage inputs of most throttle position (TP) sensors may, for example, be coordinated with the barometric pressure (BARO), manifold absolute pressure