How many fuel injectors does a 4 cylinder car have?

In most four-cylinder engines, there are four fuel injectors—one for each cylinder—regardless of whether the system is port fuel injection (PFI) or gasoline direct injection (GDI). However, some dual-injection setups add a second injector per cylinder, bringing the total to eight.

Baseline configuration: one injector per cylinder

That arrangement is the standard for the vast majority of four-cylinder engines. Each cylinder receives fuel through a single injector, either in the intake manifold (PFI) or directly into the combustion chamber (DI).

• Port fuel injection (PFI): four injectors sit in the intake manifold, one per cylinder.


• Gasoline direct injection (DI): four injectors are placed directly at or near each cylinder to spray fuel into the combustion chamber.


• Dual-injection systems (GDI plus port injection): eight injectors in total—two per cylinder (one direct injector and one port injector)—used to optimize performance, cold-start behavior, and emissions on some modern engines.

For most drivers, the standard four-injector setup is what you’ll encounter. If a car uses dual injection, the engine’s owner manual or service documentation will confirm the exact injector layout.

Additional considerations for maintenance and repair

Knowing the injector count matters when diagnosing misfires, fuel pressure issues, or injector-related faults, and it can influence replacement cost and procedure.

How to determine the injector count on your engine

Check the vehicle’s service manual, a factory diagram under the hood, or the engine’s labeling. A quick visual check can confirm whether there are four injectors or eight (two per cylinder) on your four-cylinder engine.

Impact on repairs and fuel economy

Engines with dual injectors per cylinder can be more complex to service and may have different maintenance intervals for the injectors and the fuel rail. However, the overall impact on fuel economy depends on the technology and calibration, not solely on the injector count.

Summary

The typical four-cylinder car uses four fuel injectors—one per cylinder. Some modern engines employ dual-injection systems with eight injectors, combining port and direct injection for improved performance and emissions. Always verify your specific vehicle’s configuration in the owner’s manual or service documentation.

Is there a fuel injector for each cylinder?

Gasoline direct injection (GDI) positions injectors directly inside the combustion chamber for more precise delivery and improved efficiency. Despite these differences, the number of fuel injectors per cylinder remains consistent; typically one injector services each cylinder regardless of method.

What happens if one fuel injector is bad?

If one fuel injector is bad, you will likely experience engine misfires, rough idling, and poor engine performance due to the disruption of the air-fuel mixture. Over time, this can lead to decreased fuel efficiency, higher emissions, and potentially serious engine damage like a damaged catalytic converter or internal engine wear. You may also notice a fuel smell or see the check engine light turn on. 
Immediate symptoms

• Engine misfires: The engine may "hiccup" or hesitate because one cylinder isn't firing correctly. 
• Rough idle: The engine's RPMs may fluctuate erratically or drop too low, causing the engine to vibrate or even stall. 
• Poor performance: The vehicle may have difficulty accelerating or feel sluggish due to a lack of power. 
• Check engine light: A malfunctioning injector can trigger this warning light. 
• Fuel smell: A leaking injector can cause a strong smell of gasoline. 

Potential long-term consequences

• Decreased fuel efficiency: The engine works harder to compensate, leading to more fuel consumption. 
• Increased emissions: Poor combustion from the malfunctioning injector can lead to higher emissions. 
• Catalytic converter damage: Unburnt fuel can be sent to the catalytic converter, potentially leading to its failure. 
• Serious engine damage: Over time, the imbalance can cause excessive heat and wear on internal components like pistons and valves, leading to costly repairs. 

What to do

• Do not ignore it: Driving with a bad fuel injector is not recommended, as it can cause further damage and leave you stranded. 
• Have it inspected: Take your vehicle to a mechanic to properly diagnose the issue. 
• Get it replaced: The injector will need to be replaced to restore proper engine function. 
• Consider replacing all at once: It is often recommended to replace all fuel injectors at the same time, as the others may be nearing the end of their lifespan as well. 

Is replacing a fuel injector a big job?

Replacing a fuel injector is not a simple job; the difficulty varies significantly depending on the vehicle, ranging from a relatively easy DIY task on some older models to a very difficult "nightmare" job on others. Accessing the injectors is the main factor—some are easily visible and on a rail on the exterior of the engine, while others are buried under the intake manifold, requiring the removal of many other components like the throttle body, alternator, and various hoses and lines. Improper installation can cause serious problems, so it often requires specialized tools and a high level of mechanical confidence, and many people opt to have a professional mechanic perform the work to ensure it is done correctly and efficiently.
 
Factors that determine the difficulty
This video demonstrates the process of replacing a fuel injector: 56sFourby4DieselYouTube · Nov 25, 2022

• Vehicle and Engine Design: The biggest variable is the engine layout and where the fuel injectors are located. 
  • Easier: On some older cars, injectors are external and easily accessible. 
  • Difficult: On many modern cars, especially V-6 or V-8 engines, the injectors are under the intake manifold, requiring extensive disassembly. 
• System Type:
  • Throttle body injection: Often a single or dual unit that's easy to access. 
  • Multi-port fuel injection: Requires removal of the fuel rail, which can be simple or complex depending on access. 
• Specialized Tools: Some repairs require specialized tools for removal, cleaning, and testing, such as a slide hammer or injector seat cleaning tool. 
• Risk of Error:
  • A failed or incorrect installation can lead to much bigger and more expensive problems down the road. 
  • Even a small amount of dirt entering the system can cause issues, so working in a clean environment is critical. 

When to consider professional help

• You lack experience working on engines.
• Your vehicle's engine layout makes access extremely difficult.
• You do not have the specialized tools required.
• You want to ensure the job is done correctly to avoid further damage. 

If you're a DIYer

• Assess your skill level: Be honest about your mechanical experience. 
• Consult a vehicle-specific guide: Find a guide or video for your exact make and model to see the specific steps involved. 
• Gather the right tools: Make sure you have all necessary general and specialized tools before starting. 
• Take your time: A full set can take 2–6 hours for a professional, so plan for a significant amount of time. 

How much does it cost to replace 4 fuel injectors?

Replacing four fuel injectors typically costs $1,200 to $2,500 for a four-cylinder engine, while V8 or high-performance engines can cost $2,500 to over $4,000. The total price depends on the vehicle's make and model, the cost of parts (which can range from $100-$1,000 per injector), and labor rates. Replacing multiple injectors at once is often more cost-effective because labor costs don't scale linearly with each additional injector. 
Cost breakdown

• Parts: Fuel injector prices vary significantly, from a couple of hundred dollars to over $1,000 per part for high-end or diesel vehicles. 
• Labor: While the first injector can take 2-5 hours of labor, subsequent injectors on the same engine bank add significantly less time (30-60 minutes). 
• Total for a four-cylinder engine: Expect a total cost between $1,200 and $2,500. 
• Total for a V8 engine: Expect a total cost of $2,500 to $4,000 or more. 
• Diagnostic fees: You may also encounter diagnostic fees, which can range from $100 to $300 if not included in the quote. 

Why replacing multiple injectors is recommended

• Cost-efficiency: It is often cheaper to replace all injectors on one engine bank at the same time. This avoids paying for labor multiple times as the other injectors fail over time.
• Preventative maintenance: It's common for multiple injectors to wear out around the same time. Replacing them all at once is a way to address future issues before they happen.