1) When analysing and evaluating unequal cylinder power balance results, what are five [5] engine or fuel system components this?

2) A fuel pressure test reveals higher than normal fuel pressure. Describe the steps you would take to analyse and evaluate this concern to determine the root cause of the problem?

3.    Name the four [4] different types of petrol fuel systems?

4.    On the common-rail fuel injection system, what does the high-pressure stage consist of?

5.    Why are the high-pressure fuel lines in a common-rail fuel injection system different to other diesel systems?

6.    Describe the process to check for combustion gas leakage into the cooling system?

Answer:

1. In analyzing and evaluating unequal cylinder power balance results, the five engine or fuel system components are piston rings, valve train, head gasket, fuel system, or even the ignition system.

2. If a fuel pressure test reveals higher than the normal fuel pressure you can use these steps to evaluate the concern:

• Use a fuel pressure gauge to test fuel pressure.
• Check  the service manual for proper fuel pressure for the engine being tested.
• Find the fitting. If not, a special fitting  from a fuel injection kit will be required.
• After properly installing the gauge, secure it, and turn the ignition key to the ON position, it should indicate fuel pressure.
• Start the engine; the fuel pressure should remain the same.
• Snap the throttle and make sure it increases; this is an indication of a good fuel pump.
• Test a vacuum-operated fuel pressure regulator by removing the vacuum line while monitoring fuel pressure. The pressure should increase from 5 - 15 psi.
• A rupture fuel pressure diaphragm leaks fuel into the vacuum  line.
• Check with the manufacturer's manual for special procedures.
• Use fuel pressure regulators which can be electric or those that is controlled by a control module (PCM).

3. The four different types of Petrol fuel systems are the following:

• Carburetors - the allow petrol to be sucked into the flow of air as it enters the engine with the use of a principle called 'venturi effect'.
• Mechanical / continuous petrol injection systems - systems which usually have one petrol injector per cylinder.
• Electronic fuel injection (EFI) (Throttle body injection type) - not to be confused with multipoint or sequential petrol injection systems which are described below, these systems do not have one petrol injector per engine cylinder. The petrol injectors (usually one or two) are installed just after the throttle valve of the engine, the air and fuel flow together from this point through the inlet manifold to the individual cylinders so the fuel from a single petrol injector might be distributed to all engine cylinders.
• Direct injection - systems for petrol engines have been around a long time in one form or another, there are two main types. The older systems that were around before the now common computer controlled EFI systems (described above) were completely mechanical and worked in the same kind of way as the fuel system on many diesel engines, using a mechanical pump to inject fuel straight into the engine cylinders.

4. The high-pressure stage of the common-rail system is divided into three sections: pressure generation, pressure storage, and fuel metering

5.  Common rail diesel uses a single fuel rail to supply fuel to the electronically controlled injectors under extremely high pressure. The engine computer controls fuel injection duration and timing to allow for higher efficiency and power. All parameters can be monitored and adjusted by the ECU while the conventional diesel is known as mechanical which is controlled by an engine driven injection pump and uses injectors which open upon reaching enough fuel pressure provided by the injection pump. Some injectors are controlled by engine oil pressure which is known as HEUI. HEUI - How High-Pressure Oil Injection Systems Work - Diesel Power Magazine Mechanical diesel injection systems are reliable and easy to work on but they lack the efficiency and lower emissions of electronically controlled systems.

6.  Here are the steps or processes to check for combustion gas leakage into the cooling system:

• Fill the radiator to about 1/2-inch below the bottom of the filler neck.
• Wipe the sealing surface and attach the tester.
• Operate the pressure tester pump to apply pressure no greater than 3 psi above the manufacturer's specification.
• If the pressure holds steady; the system is not leaking.
• If the pressure drops; there are leaks.
• Check the pressure tester's needle with the engine warm and at about 3,000 rpm. A fluctuating needle may indicate an exhaust gas leak.