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Title / Demonstrate knowledge of diesel engine air intake and exhaust systems, and inspect and test them
Level / 3 / Credits / 6
Purpose / This unit standard is for people in the automotive repair industry. People credited with this unit standard are able to: demonstrate knowledge of an induction system on a diesel engine; demonstrate knowledge of an exhaust system on a diesel engine; demonstrate knowledge of the operating conditions for a vehicle and/or machine equipped with a turbocharged engine; inspect and test the induction system on a diesel engine for faults; and inspect and test the exhaust system on a diesel engine for faults.
Classification / Motor Industry > Automotive Fuel Systems and Exhaust
Available grade / Achieved
Explanatory notes
1The following legislation and amendments are required to be consulted and followed where applicable:
Health and Safety in Employment Act, 1992.
2Reference to suitable tools and test equipment means industry approved tools and equipment that are recognised within the industry as being the most suited to complete the task to a professional and competent manner with due regard to safe working practices.
3Unit standard Range for this unit standard includes both two and four stroke diesel engines.
4Because of the particular nature of this unit standard, it is essential that the practical assessment evidence is obtained from commercial jobs in the workplace under normal workplace conditions.
Outcomes and evidence requirements
Outcome 1
Demonstrate knowledge of an induction system on a diesel engine.
Evidence requirements
1.1Air volumes required of an engine are compared.
Rangenaturally aspirated, with a turbocharger, with a blower.
1.2Main components of a turbocharger system are identified according to manufacturer’s workshop manual illustrations.
Rangeair intake, compressor, turbine, exhaust manifold, wastegate, oil supply, intercooler.
1.3Principles of turbocharging are described according to engine manufacturer’s specifications.
Rangeturbocharger location, volumetric efficiency, engine performance, boost pressure, exhaust gas circulation, lubrication and cooling, pressure control including electronic.
1.4Principles of a Rootes type blower are described according to engine manufacturer’s specifications.
Rangeblower location, volumetric efficiency, engine performance, forced air pressure circulation, lubrication and cooling, pressure control.
Outcome 2
Demonstrate knowledge of an exhaust system on a diesel engine.
Evidence requirements
2.1Exhaust size and air flow rates of an exhaust system are compared.
Rangenaturally aspirated engine, turbocharged engine.
2.2Requirements of an exhaust system to produce back pressure according to manufacturer’s specifications are determined and calculated.
Outcome 3
Demonstrate knowledge of the operating conditions for a vehicle and/or machine equipped with a turbocharged engine.
Evidence requirements
3.1Driver operational requirements for a turbocharged engined vehicle and/or machine are identified.
Rangestart-up procedures, shut-down procedures, servicing requirements.
3.2Importance of specified clean oil delivery to the turbocharger is identified.
Rangevehicle or machine manufacturer’s engine oil specifications, oil and filter change recommendations, turbocharger oil requirements.
3.3Hazards of unfiltered air entering the turbocharger system are identified.
Rangedamage to components, dusty operating conditions, air intake condition.
Outcome 4
Inspect and test the induction system on a diesel engine for faults.
Evidence requirements
4.1Safe working practices are observed throughout the task.
Rangepersonal safety; safety of others; equipment, vehicle, and machine safety.
4.2Test equipment is mounted on the engine to enable inlet system restrictions to be identified.
4.3Air pressure readings are measured according to manufacturer’s instructions, and the results are recorded.
4.4Induction system is inspected according to manufacturer’s workshop manual instructions, and any faults found are reported to the supervisor.
Rangescoop, prefilters, filters, pipework, elements, hoses, clamps, mounts.
Outcome 5
Inspect and test the exhaust system on a diesel engine for faults.
Evidence requirements
5.1Safe working practices are observed throughout the task.
Rangepersonal safety; safety of others; equipment, vehicle, and machine safety.
5.2Suitable tools and test equipment are selected according to manufacturer’s specifications, and used to enable the system to be inspected and tested.
5.3Test equipment is mounted on the engine to enable exhaust system restrictions to be identified.
5.4Exhaust system is inspected according to manufacturer’s workshop manual instructions, and any faults found are reported to the supervisor.
Rangeflanges, pipework, mufflers, spark arrestors, mountings.
5.5Exhaust system faults and their causes identified by the test gauge readings are noted.
5.6Fuel lift tube, screens, and primary and secondary filters are inspected and cleaned and/or replaced according to manufacturer’s recommendations.
5.7Fuel hoses and connections are inspected and those found faulty are repaired and/or replaced according to manufacturer’s specifications.
5.8Fuel system is bled of air as prescribed by the engine manufacturer.
Replacement information / This unit standard and unit standard 930 have been replaced by unit standard 24178, unit standard 24179, and unit standard 24180.This unit standard and unit standard 15403 replaced unit standard 903.
This unit standard is expiring. Assessment against the standard must take place by the last date for assessment set out below.
Status information and last date for assessment for superseded versions
Process / Version / Date / Last Date for AssessmentRegistration / 1 / 26 February 1999 / 31 December 2016
Review / 2 / 25 January 2008 / 31 December 2020
Rollover / 3 / 19 November 2010 / 31 December 2020
Rollover / 4 / 22 August 2014 / 31 December 2020
Consent and Moderation Requirements (CMR) reference / 0014
This CMR can be accessed at
Please note
Providers must be granted consent to assess against standards (accredited) by NZQA, before they can report credits from assessment against unit standards or deliver courses of study leading to that assessment.
Industry Training Organisations must be granted consent to assess against standards by NZQA before they can register credits from assessment against unit standards.
Providers and Industry Training Organisations, which have been granted consent and which are assessing against unit standards must engage with the moderation system that applies to those standards.
Requirements for consent to assess and an outline of the moderation system that applies to this standard are outlined in the Consent and Moderation Requirements (CMR). The CMR also includes useful information about special requirements for organisations wishing to develop education and training programmes, such as minimum qualifications for tutors and assessors, and special resource requirements.
NZ Motor Industry Training Organisation (Incorporated)SSB Code 101542 / New Zealand Qualifications Authority 2018