The Next Evolution Of Fuel Injection
You may soon see a vehicle that has both direct fuel injection and port fuel injection. It could be a Toyota, Ford or other make. It can be confusing because for a long time we were told that direct fuel injection was better than port fuel injection. To get the best power and economy from an engine, some engineers realized that both injection systems could be used on the same engine.
Air Filter And Fuel Trim Diagnostics
The modern engine measures two things extremely well, the amount of air going into the combustion chamber with the mass airflow sensor (MAF), and the byproducts that are generated by the combustion event with the oxygen sensor. These measurements allow the engine’s computer to put the right amount of fuel and spark into the cylinder to give the most efficient and cleanest combustion event.
Fuel Pump Codes And Control: Keeping Pressure In The Zone
Since the fuel pump module needs information for various sensors, it usually communicates on a serial data bus. If modules are not communicating, the fuel pump can’t be adequately controlled. The key to investigating these problems is to communicate with different modules to see what data PIDs are present and which ones are missing.
VIDEO: Diagnosing Intermittent Fuel Pressure Issues
Andrew Markel discusses fuel pressure, and the different ways to diagnose issues without using a pressure gauge. Sponsored by Auto Value and Bumper to Bumper.
Direct Injection Logic: How The High-Pressure Fuel Pump Solenoid Works
A direct injection fuel pump can’t increase its speed independent of the engine to increase it’s output or pressure, so it has to control the volume of fuel that is compressed. This relationship is what makes direct injection high-pressure fuel pumps a mystery to some technicians and even engineers. But once you understand the relationship between the pump and control solenoid, your diagnostic skills will grow.
The Carbon Deposit Conundrum
Engine carbon deposits have been around for more than 100 years. They start out as fresh oil and gasoline. The engine uses heat, compression and combustion to turn most of the fuel into power. But, during some combustion events, a droplet of fuel or oil is transformed into a substance that can become a carbon deposit. This typically happens when there are conditions that are outside of the normal operating conditions.
Direct Fuel Injection Diagnostics
Direct injection is becoming standard on more and more late-model vehicles. These systems can be a diagnostic challenge but, with the right foundation, problems can be solved profitably.
Ford Tech Tip: Gas Nozzle Stuck In Filler Neck
Some vehicles equipped with the Easy Fuel Capless Fuel System may exhibit a concern where a fuel nozzle cannot be inserted and/or removed. This concern may be caused by a problem with the fuel station nozzle. The sleeve at the tip of the spout may be missing, not allowing the nozzle to be inserted, or could be loose/gapped not allowing the nozzle to be removed once inserted.
Scan Tool Freeze Frames: Using Generic Data To Make A Specific Diagnosis.
As part of OBDII, Mode$02 for the logging or freeze frame data was created. This diagnostic protocol saves data PIDs and information when a code is set. In 1995, freeze frame gave technicians a powerful diagnostic tool that was previously only available on expensive factory tools.
Using Fuel And Ignition Waveforms Together
Fuel injector and secondary ignition waveforms can show the condition of the fuel and ignition system, and combined they can give you new insights on misfires and if they are related to the fuel or ignition system. Scan tools can tell you if there is a misfire and which cylinder is misfiring. Rarely will you be able to determine if it is the ignition coil and spark plug or if the fuel injector is causing a rich or lean condition. With a scope that has the correct probes, it is possible.
Mazda Tech Tip: Sulfur Or Rotten Egg Smell/Odor From The Exhaust
On some Mazda vehicles, a sulfur smell or rotten egg odor may be noticed coming from the exhaust system. The odor is usually noticed after a cold start, fast idle, extended periods of idling and full-throttle acceleration. The sulfur smell is not an indication of an engine concern and will not cause reduced driveability or durability of the engine or any of its emission components.
Pulse-Width Fuel Pump Diagnostics
You will see only one fuel line going to the fuel rail on most late-model vehicles. Instead of using an engine vacuum routed to a pressure regulator under the hood, returnless systems use engine data and vary the speed of the electric pump to meet fuel pressure and volume requirements without having to bleed off and return it to the tank when the engine does not need it.
