ISO 21042:2026

Gasoline engines with direct fuel injection (GDI engines) — Installation of the high-pressure fuel pump to the engine

This document specifies dimensions required for the installation and integration of the high pressure fuel pump in gasoline (GDI) engines. The location of the fuel connections and the dimensions of the pump outside shape are not defined since they vary according to the manufacturer of the pump and to the particular application.

Moteur à essence à injection directe (moteurs GDI) — Installation de la pompe d'injection de carburant à haute pression sur le moteur

General Information

• Status: Published
• Publication Date: 05-Feb-2026
• ICS: 43.060.40 - Fuel systems
• Technical Committee: ISO/TC 22/SC 34 - Propulsion, powertrain and powertrain fluids
• Drafting Committee: ISO/TC 22/SC 34/WG 2 - Injection equipment
• Current Stage: 6060 - International Standard published
• Start Date: 06-Feb-2026
• Due Date: 28-Apr-2026
• Completion Date: 06-Feb-2026

Relations

• Revises: ISO 21042:2018 - Gasoline engines with direct fuel injection (GDI engines) — Installation of the high pressure fuel pump to the engine
• Effective Date: 07-Jan-2025

Overview

ISO 21042:2026 is an international standard developed by ISO for the automotive sector, specifically focused on gasoline engines with direct fuel injection (GDI engines). This standard details the dimensional and interface requirements for installing high-pressure fuel pumps onto GDI engines. By setting clear guidelines for integration, ISO 21042:2026 supports consistent assembly practices, improved component compatibility, and seamless collaboration between fuel pump suppliers and engine manufacturers.

Modern gasoline direct injection engines rely on high-pressure fuel pumps to deliver precise amounts of fuel at elevated pressures, optimizing engine performance, fuel efficiency, and emissions. However, variations in pump design and engine applications make standardization of installation parameters essential to ensure performance and reliability.

Key Topics

• Dimensional Requirements
  • Defines key flange, bolt, and bore dimensions for mounting high-pressure fuel pumps to gasoline engines.
  • Ensures repeatable interface standards at the cylinder head for various engine and pump designs.
• Pump Interface and Mounting
  • Specifies the principle of installation, including the integration of the pump housing, sealing arrangements, mounting flanges, and guiding components.
• Connector Specifications
  • Outlines standards for low-pressure (inlet) and high-pressure connectors, including reference to ISO 13948-2, ISO 18418-1, ISO 2974, and SAE J2044.
• Installation Best Practices
  • Provides recommendations for component lubrication, assembly orientation, and debris management to promote system durability and reduce maintenance needs.

Applications

The guidelines laid out in ISO 21042:2026 are essential across automotive design and manufacturing, including:

• Automotive OEMs and Engine Builders
  • Streamlines integration of high-pressure fuel pumps irrespective of specific pump designs or engine models, aiding in global harmonization of GDI engine development.
  • Ensures reliable sealing, secure mounting, and efficient fuel transfer, supporting overall engine performance and compliance with emission standards.
• Component Suppliers
  • Enables fuel pump suppliers to design products compatible with a wide range of engines, reducing engineering lead time and minimizing installation errors.
• Aftermarket and Service Workshops
  • Provides reference dimensions and connector standards, facilitating easier replacements, retrofits, and repairs of high-pressure fuel pumps in GDI engines.
• Regulatory Compliance
  • Supports industry-wide consistency, facilitating adherence to environmental regulations and automotive interoperability requirements.

Related Standards

ISO 21042:2026 makes reference to several important standards for connector and installation specifications, including:

• ISO 2974 – Diesel engines - 60° concave cones for high-pressure fuel injection components
• ISO 13948-2 – Diesel engines - Fuel injection pumps and fuel injector low-pressure connections - Non-threaded connections
• ISO 18418-1 – Gasoline engines - High pressure liquid fuel supply connectors - 60° concave cone connectors
• SAE J2044 – Quick Connect Coupling Specification for liquid fuel and emissions systems

Additional related standards for pipe assemblies and cleanliness assessment (ISO 18418-2, ISO 19724) support comprehensive quality assurance for fuel injection components in GDI engines.

Summary

ISO 21042:2026 delivers a robust and consistent framework for the installation of high-pressure fuel pumps in gasoline direct injection engines. By specifying key dimensional requirements and referencing associated connector standards, it assists manufacturers, suppliers, and service organizations in ensuring optimal pump performance, safety, and long-term reliability. Adopting ISO 21042:2026 is essential for achieving efficient assembly, compatibility, and compliance in the rapidly advancing field of GDI engine technology.

Standards Content (Sample)

International
Standard
ISO 21042
Second edition
Gasoline engines with direct
2026-02
fuel injection (GDI engines) —
Installation of the high-pressure
fuel pump to the engine
Moteur à essence à injection directe (moteurs GDI) — Installation
de la pompe d'injection de carburant à haute pression sur le
moteur
Reference number
© ISO 2026
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
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Phone: [phone]
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Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Dimensions and tolerances . 1
4.1 General .1
4.2 High-pressure pump interface .1
4.3 Low-pressure connector .4
4.4 High-pressure connector . .4
4.5 Lubrication .4
Bibliography . 5

iii
Foreword
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This document was prepared by Technical Committee ISO/TC 22, Road vehicles, Subcommittee SC 34,
Propulsion, powertrain and powertrain fluids.
This second edition cancels and replaces the first edition (ISO 21042:2018), which has been technically
revised.
The main changes are as follows:
— changed the use of non-inclusive terminology.
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