The Mazda ZJ30 is a 1,998 cc, inline‑four naturally aspirated petrol engine produced since 2019. It features a dual overhead camshaft (DOHC) layout with both intake and exhaust variable valve timing (VVT), delivering 118 kW (160 PS) and 200 Nm of torque. The engine employs a high compression ratio and an Atkinson-cycle-inspired combustion strategy to enhance thermal efficiency while maintaining responsive low-end performance.
Fitted to the Mazda3 (BM/BP), CX-30, and CX-5 (second generation facelift), the ZJ30 was engineered for balanced urban and highway driving, prioritizing refinement, fuel economy, and emissions compliance. Emissions standards were met through direct gasoline injection, a three-way catalytic converter, and exhaust gas recirculation (EGR), ensuring all variants meet Euro 6d-TEMP and Euro 6d standards.
A documented operational consideration is increased sensitivity to fuel quality in early production units; this issue is highlighted in Mazda Service Information Bulletin SI-19-007. Use of fuel containing excessive ethanol or contaminants can cause misfires and injector fouling. Mazda updated fuel system calibration and introduced stricter fuel specification requirements in mid-2020 production.
Mazda
Production from 2019–2020 meets Euro 6d-TEMP standards; 2021–present models meet Euro 6d standards (VCA UK Type Approval #VCA/EMS/8891).
The Mazda ZJ30 is a 1,998 cc inline‑four naturally aspirated petrol engine engineered for compact and mid-size vehicles (2019–present). It combines gasoline direct injection with dual continuously variable valve timing to deliver refined power delivery and efficient cruising. Designed to meet Euro 6d emissions standards, it balances everyday performance with reduced environmental impact.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,998 cc | |
| Fuel type | Petrol | |
| Configuration | Inline‑4, DOHC, 16‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 83.5 mm × 91.2 mm | |
| Power output | 118 kW (160 PS) | |
| Torque | 200 Nm @ 4,000 rpm | |
| Fuel system | Gasoline Direct Injection (GDi) | |
| Emissions standard | Euro 6d-TEMP (2019–2020); Euro 6d (2021–present) | |
| Compression ratio | 13.0:1 | |
| Cooling system | Water-cooled | |
| Timing system | Chain-driven | |
| Oil type | Mazda Genuine Oil 0W-20 | |
| Dry weight | 112 kg |
The high-compression GDi system provides strong throttle response and improved thermal efficiency but demands strict adherence to 10,000 km oil change intervals using Mazda Genuine Oil 0W-20 to prevent carbon accumulation on intake valves and maintain injector integrity. Use of fuel exceeding 10% ethanol content may cause misfires and corrosion in fuel lines, as noted in Mazda SIB SI-19-007. Extended idling and frequent short trips increase deposit formation. Chain tensioner wear is not a documented concern; replacement is only required during major service intervals.
Oil Specs: Requires Mazda Genuine Oil 0W-20 specification (Mazda SIB SI-19-007). Supersedes ACEA C2 requirements.
Emissions: Euro 6d-TEMP certification applies to 2019–2020 models only (VCA Type Approval #VCA/EMS/8891). Euro 6d compliance is mandatory for 2021–present models.
Power Ratings: Measured under ISO 1585 standard. Power figures apply to standard-output variants only (Mazda Group PT-2024).
Mazda Technical Information System (TIS): Docs S-1201, SI-19-007
VCA Type Approval Database (VCA/EMS/8891)
Mazda EPC Document MZ-2023-011
Mazda Group Parts Technical Manual PT-2024
Mazda Lightweight Engineering Report #LWR-ZJ
The Mazda ZJ30 was used across Mazda's BM/BP/BX platforms with transverse mounting. This engine received platform-specific adaptations—revised intake manifold routing in the Mazda3 and modified ECU calibration in the CX-30—and from 2021 the facelifted models adopted revised cylinder head port geometry and enhanced EGR cooler design, creating interchange limits. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped vertically on the right cylinder head near the alternator mount (Mazda TIS Doc. S-1201). The 7th VIN digit indicates engine family ('K' for ZJ30 series). Pre-2021 models feature a single-stage VVT system with a distinctive black plastic intake manifold cover. Post-2021 units have a redesigned intake port geometry, a metallic intake manifold, and an upgraded EGR cooler. Critical differentiation from ZJ31: ZJ30 uses GDi only; ZJ31 uses combined port and direct injection. Service parts require exact model year verification - air intake kits for pre-2021 models are incompatible with post-facelift units due to revised throttle body sensor placement and ECU calibration (Mazda SIB SI-19-007).
The ZJ30's primary reliability risk is intake valve carbon buildup, with elevated incidence in stop-start urban use. Mazda internal data from 2022 reported a moderate incidence of misfire-related warranty claims in early 2019–2020 builds, while UK VCA MOT statistics show a significant portion of emissions failures correlate with intake valve clogging in city-driven vehicles. Frequent short-trip driving and extended idling accelerate deposit formation, making induction cleaning and fuel quality critical.
Analysis derived from Mazda technical bulletins (2019–2024) and UK VCA MOT failure statistics (2020–2024). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about MAZDA ZJ30.
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