Explain the features of port and direct injectors and the different testing methods without removing the injectors from the vehicle. (60 - 100 words)

Explain the operation of the variable intake manifold, including the benefits provided for low and high rpm? (50 – 70 words)

Why is it important to loosen the cylinder head bolts in the recommended order?

A lawnmower stops running after a short period of time. The fuel tank filler cap is removed and an almost fuel tank of fuel is found, so the cap is reinstalled and the engine restarted. The engine runs again for a short time and then dies so the cap is removed again and the process repeats. Tech a says the problem may be due to a clogged vent in the fuel cap. The b says that the intake mainfold gasket may be defective. Who is correct?

Identify two (2) mechanical components that are most likely to cause abnormal noises in a diesel engine and briefly explain the associated testing procedure used to confirm the fault. (70 - 140 words)