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Title / Describe the operation of a diesel fuel system and perform minor servicing tasks
Level / 2 / Credits / 3
Purpose / This unit standard is for people who wish to enter or are employed in the automotive repair industry. People credited with this unit standard are able to: demonstrate knowledge of diesel oil as an automotive fuel; demonstrate knowledge of a diesel fuel system; remove and replace diesel fuel injectors; remove and replace a fuel filter; and bleed air from a diesel fuel system.
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 means industry approved tools 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.
Outcomes and evidence requirements
Outcome 1
Demonstrate knowledge of diesel oil as an automotive fuel.
Evidence requirements
1.1The properties of a diesel fuel are described according to oil company specifications.
Rangeviscosity, flashpoint, self-ignition temperature, ignition qualities, sulphur content, cloud point, effects of contamination, energy content.
1.2The different grades of diesel fuel are defined.
Rangecetane number, summer and winter fuels.
Outcome 2
Demonstrate knowledge of a diesel fuel system.
Evidence requirements
2.1The major components of the fuel system, their location on the vehicle, and the fuel flow path are described according to vehicle manufacturer’s workshop manual descriptions.
Rangefuel tank, piping, filters, lift pump, injection pump, injectors.
2.2The purposes of the lift pump, the injection pump, and the injectors are described according to manufacturer’s manual descriptions.
2.3The major differences between an in-line injection pump and a rotary injection pump are described according to manufacturer’s manual descriptions.
Rangeoverall pump shape, number of pumping elements.
2.4Safety precautions when working on vehicles equipped with electronically controlled diesel fuel systems are described according to vehicle manufacturer’s workshop manual instructions.
Outcome 3
Remove and replace diesel fuel injectors.
Rangenon-metering injectors.
Evidence requirements
3.1Safe working practices are observed throughout the task.
Rangepersonal safety, safety of others, equipment and vehicle safety, high pressure fuel safety.
3.2Suitable tools are selected for removing and replacing injectors.
3.3The injectors are disconnected and removed without damage to the injectors, pipes, and connections.
3.4Replacement injectors are installed and connected to manufacturer's specifications.
Outcome 4
Remove and replace a fuel filter.
Evidence requirements
4.1Safe working practices are observed throughout the task.
Rangepersonal safety, safety of others, equipment and vehicle safety, fuel safety.
4.2Suitable tools are selected for removing and replacing a fuel filter.
4.3The fuel filter element is removed without damage to the fuel casing and the element, and any other componentry, and wasted fuel is disposed of in a manner that will not cause a hazard.
4.4A new filter element and gasket are selected, fitted, and tightened to manufacturer's specifications, ensuring that dirt and moisture are kept out.
Outcome 5
Bleed air from a diesel fuel system.
Evidence requirements
5.1Safe working practices are observed throughout the task.
Rangepersonal safety, safety of others, equipment and vehicle safety, high pressure fuel safety.
5.2The need for bleeding air from a diesel fuel system is determined from the nature of work undertaken on the system.
5.3The fuel tank is checked to ensure sufficient fuel is available to carry out the task successfully.
5.4Air is bled from the system in accordance with manufacturer's instructions and specifications.
Replacement information / This unit standard has been replaced by unit standard 21677 and unit standard 21692.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 / 28 February 1993 / 31 December 2016
Review / 2 / 4 August 1995 / 31 December 2016
Revision / 3 / 30 October 1997 / 31 December 2016
Revision / 4 / 28 May 1998 / 31 December 2016
Review / 5 / 20 December 1998 / 31 December 2016
Revision / 6 / 13 March 2001 / 31 December 2016
Revision / 7 / 16 October 2003 / 31 December 2016
Rollover / 8 / 25 July 2006 / 31 December 2020
Rollover / 9 / 19 November 2010 / 31 December 2020
Rollover / 10 / 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