Ordinary level 2026 South West mock mechanical technology guide
Ordinary level 2026 South West mock mechanical technology guide
Question 1: PETROL INJECTION
Figure 1 is that of a petrol injection system.
a- What type of petrol injection system is shown above? (1 mark)
L-Jetronic injection system.
b- Fill the table below. (3.75 marks)
| Ref. | Name of part (0.25mark x 5) | Function (0.25mark x 5) |
| 4 | Electronic Control Unit (ECU) | It controls the opening of the injectors based on the input sensors information. |
| 6 | Pressure regulator | It returns excess fuel back to the tank. |
| 9 | Throttle position valve | It informs the electronic control unit of the throttle position. |
| 10 | Air flow sensor | It informs the electronic control unit of the quantity of air entering the engine. |
| 15 | Auxiliary air device | It supplies engine with additional air during warm-up phase. |
c- Give two parameters required by the ECU to determine the quantity of fuel to be injected. (1mark x 2 = 2 marks)
| – The amount of air flowing into the engine; | – The position of the crankshaft; | – The engine’s temperature. |
| d- What is the effect on engine performance if part (11) fails? | (1.25 mark) |
– Poor or rich air/fuel mixture; – Engine misfires; – Fuel consumption increases;
– CO2 emission increases; – Loss of power.
e- Part (2) is the pump. Give any two signs of a malfunctioning fuel pump as the engine runs. (1mark x 2 = 2 marks)
– Hard starting; – Engine stalls; – Engine jerks; – Loss of power.
Question 2: GEARBOX
Figure 2 is the diagram of one type of vehicle manual shift gearbox.
| a- What type of manual gearbox is shown in figure 2 above? | (1 mark) |
| Sliding mesh manual gearbox. | |
| b- State three (03) requirements of an automobile manual gearbox. (1mark x 3 = 3 marks) | |
| – It must have a neutral point; | – It must be able to obtain reverse; |
– It must be able to vary the forward gears.
c- Give the names of parts 1, 2, 3 and 4 of figure 2 above. (2 marks)
| N° | Name (0.5mark x 2) | N° | Name (0.5mark x 2) |
| 1 | Input shaft | 3 | Reverse idler |
| 2 | Output shaft | 4 | Lay shaft |
d- What is the major problem with this type of gearbox? (1 mark)
Excessive wear due to the movement of the output shaft gear wheels to obtain gear changing
