Exam 31: Fuel Injection System Diagnosis and Service

The engine must be at normal operating temperature before the ECT sensor is tested.

Which of the following should be checked before proceeding with specific fuel injection and electronic control testing?

Why will a leak in the ductwork between the MAF and the throttle body have an effect on the driveability of the vehicle?

A good injector makes a rhythmic clicking sound as the injector is energized and de-energized several times each second.

An injector balance test requires an injector pulse tester and a ______..

Short-term and long-term fuel trim readings are being discussed. Technician A says a scale of 0 to 255 is used. Technician B says percentage is used. Who is correct?

Technician A checks GDI [gasoline direct injectors] injectors with a pulse tester. Technician B test GDI injectors with an ohmmeter. Who is correct?

____________________ are used to locate the source of an internal fuel leak that allows the fuel pressure to drop to zero PSI immediately after engine shut down.

When is a grounding strap required?

Technician A says a rich air/fuel ratio may be caused by low fuel pump pressure. Technician B says a rich air/fuel ratio may be caused by a defective engine coolant temperature sensor. Who is correct?

What could a leak in the fuel pressure regulator or the fuel pump check valve that allows the fuel pressure to slowly bleed down after engine shut down cause?

Operation of an O₂ sensor is checked with a(n) _____.

The IAC motor cannot be actuated with a scan tool.

What is the difference between short-term and long-term fuel trim?

The best tool to verify that the engine is running excessively rich or lean is a(n) ______.

In sequential fuel injection systems, each injector has its own electrical ____________________ circuit and wiring.

What problem may result from dirt buildup on an engine's throttle plates?

Static test replacement computers, modules, and computer chips prior to installation.

If liquid gasoline is found in the fuel pressure regulator vacuum hose, ______.

The voltage signal from most O₂ sensors varies between _____ and _____ volt(s).