2004 Infiniti G35 Sedan Fuel Pump: Symptoms, Replacement Guide, and Best Options

If you own a 2004 Infiniti G35 Sedan with the 3.5L VQ35DE engine and you are experiencing hard starting, engine sputtering, stalling, or a loud whining noise coming from the rear seat area, the fuel pump is very likely the culprit. The stock fuel pump in the 2003 G35 delivers a maximum of 90-120 liters per hour (LPH) and is located inside the fuel tank under the rear seat on the passenger side . Replacing a failing fuel pump promptly is critical to prevent being stranded or causing further engine damage, and the total cost can range from as low as $90 for a basic pump to over $1,400 for professional installation . This guide covers everything you need to know about the 2004 Infiniti G35 Sedan fuel pump, including symptoms of failure, how to diagnose the problem, step-by-step replacement instructions, top brand recommendations, upgrade options, and maintenance tips to extend the life of your new pump.

Understanding the Fuel Pump System in the 2004 G35 Sedan

The 2004 Infiniti G35 Sedan is equipped with a dual fuel pump system, which sets it apart from many other vehicles in its class that rely on a single pump . This design choice reflects the car's performance-oriented nature, ensuring consistent fuel delivery, especially during high-performance driving . The main fuel pump is located under the rear seat on the passenger side, and the sub-pump is located on the other side of the fuel tank, transferring fuel from one side of the tank to the main pump side . In most cases, you only need to replace the main pump, as it is unlikely that both pumps fail at the same time . The fuel pressure for the G35 should typically be around 50-60 PSI when tested with a fuel pressure gauge .

Symptoms of a Failing Fuel Pump in Your 2004 G35 Sedan

Recognizing the signs of a bad fuel pump early can save you from a roadside breakdown. Here are the most common symptoms G35 owners report:

1. Engine sputters or stalls at high speeds. When the fuel pump cannot deliver enough fuel to keep up with the engine's demand, you may feel the car hesitate or jerk, especially under load or on the highway .

2. Loss of power during acceleration or climbing hills. A weak pump means insufficient fuel pressure reaching the injectors, resulting in sluggish performance and an inability to maintain speed .

3. Difficulty starting the engine. If the fuel pump is not building adequate pressure, the engine may crank for an extended period before firing up, or it may not start at all .

4. Loud whining noise from the fuel tank area. A healthy fuel pump produces a quiet hum for a few seconds when you turn the key to the "ON" position. A high-pitched whine or a constant loud noise indicates the pump is wearing out and should be replaced .

5. Check Engine Light comes on. Faulty fuel pumps can trigger diagnostic trouble codes (DTCs) related to fuel system pressure, such as P0462 or P0463, which indicate a fuel level sensor or fuel pump circuit issue .

Diagnosing the Fuel Pump Problem

Before diving into the replacement process, confirm that the fuel pump is indeed the issue. Use a fuel pressure gauge to test the pump's output—it should match the manufacturer's specifications, typically around 50-60 PSI for the G35 . If pressure is low or inconsistent, replacement is likely necessary . Always rule out other potential issues, such as a clogged fuel filter or faulty fuel pressure regulator, before proceeding . The fuel filter in the Infiniti G35 is a cartridge-style filter attached to the fuel pump assembly, and it is located inside the fuel tank . If the fuel pressure is higher than the specified value, you should replace the fuel pressure regulator, which is a component of the fuel pump/fuel level sensor module .

Replacement Parts and Compatibility

When it comes to replacing the fuel pump on your 2004 Infiniti G35 Sedan, you have several options. The OEM part number for the fuel pump assembly is 17040-CD000 for the 2003-2007 models . For the 2008 model, the part number is either 17040-EJ81A or 17040-JK60A . Here are some compatible replacement options:

1. MOSTPLUS Fuel Pump Assembly (17040CD000) – Compatible with 2003-2009 Infiniti G35, M35, M45, and Nissan 350Z with the V6-3.5L engine. This is a complete assembly that replaces OEM E8534M, SP4018M, and FG1084 .

2. Delphi In-Tank Electric Fuel Pump – Designed for the 2003-2006 Infiniti G35 Sedan with the 3.5L V6 engine. Delphi is a trusted name in OEM-quality fuel system components .

3. DriveBolt In-Tank Electric Fuel Pump – Another aftermarket option for the 2003-2006 Infiniti G35 Sedan with the 3.5L V6 engine .

4. SCITOO Electric Fuel Pump Assembly with Sending Unit – Compatible with 2004-2006 Infiniti G35 3.5L, 2006-2008 Infiniti M35 3.5L, and 2003-2009 Nissan 350Z 3.5L .

5. OEM Infiniti 17042-AC700 In Tank Fuel Pump Assembly – This is the genuine Infiniti part for the 2003-2006 G35 Sedan .

Step-by-Step Fuel Pump Replacement Guide

Replacing the fuel pump on your 2004 Infiniti G35 Sedan is a challenging but doable DIY project if you have basic mechanical skills . Always work in a well-ventilated area, wear safety glasses, and keep a fire extinguisher nearby . Here are the general steps:

Step 1: Relieve fuel system pressure. Locate the fuel pump fuse in the fuse box and remove it. Start the engine and let it run until it stalls, then crank the engine two or three more times to release any remaining pressure. Turn the ignition off .

Step 2: Disconnect the battery. Remove the negative battery terminal to prevent any electrical shorts or sparks .

Step 3: Drain the fuel tank. It is recommended to drain the fuel tank to about 7/8 full to make the process safer and easier . A nearly full tank can make the process more difficult and messy .

Step 4: Access the fuel pump. Remove the rear seat cushion by raising the bottom of the seat cushion to release the wire from the plastic hook, then pull the seat cushion forward to remove it . On the passenger side, you will see a metal access panel. Remove the screws or rotate the plastic clips 90 degrees to lift the panel off .

Step 5: Disconnect the wiring and hoses. Carefully disconnect the electrical connector from the top of the fuel pump assembly. Also, detach the two fuel hoses from the old pump. Be sure to attach these hoses to the new pump before installing it .

Step 6: Remove the old pump. Unscrew the retaining ring that holds the fuel pump in place. Lift the pump assembly straight out of the fuel tank. Be cautious of any remaining fuel in the assembly . Slowly pull out the fuel pump, being mindful of the black electrical hoses on the outer periphery of the pump .

Step 7: Install the new pump. Place the new pump assembly into the same position, ensuring the fuel level sensor is not damaged. Secure it with the retaining ring. Use a new O-ring and grommet, ensuring that the outlet pipes are aligned correctly . Reconnect the electrical connectors and fuel hoses .

Step 8: Reassemble and test. Replace the access panel and rear seat. Reconnect the negative battery terminal. Turn the ignition to the "ON" position without starting the engine to prime the fuel system. Check for any fuel leaks before starting the engine .

Should You Replace Just the Pump or the Entire Assembly?

When your fuel pump fails, you have two main options: replace just the pump itself, or replace the entire fuel pump module assembly. Here are some considerations:

1. Replacing just the pump – This is the more budget-friendly option. Aftermarket performance pumps like the DeatschWerks DW200 or DW300 can be installed into your existing fuel pump assembly. The installation guide for the 03-8 Nissan 350Z/Infiniti G35 shows that you need to remove the fuel temperature sensor, disconnect the electrical connectors, pull the bucket away from the center section, and pry the pump retainer off . The OE pump isolator/grommet will NOT be used when installing an aftermarket pump .

2. Replacing the entire assembly – This is the easier option and often recommended for daily drivers. A complete fuel pump assembly includes the pump, fuel level sensor, pressure regulator, and strainer all in one unit. This ensures everything works together properly and is less labor-intensive. However, it is more expensive .

Upgrading Your Fuel Pump for Better Performance

If you are looking to upgrade your fuel pump for better performance, or if you simply want a reliable replacement, there are several high-performance options available. The stock fuel pump in the 2003 G35 delivers a maximum of 90-120 LPH, but performance pumps offer significantly more flow .

1. KEMSO 340 Fuel Pump – This is a high-powered 340 LPH fuel pump designed for use in many auto applications, whether it be daily drivers, fast road, or if you're simply just looking to upgrade or replace your faulty fuel pump . It is E85 compatible and comes with a lifetime warranty .

2. DeatschWerks DW200 or DW300 – These are popular upgrade options for the G35. The installation guide for the 03-8 Nissan 350Z/Infiniti G35 shows the specific steps to install these pumps .

Performance pumps like these deliver up to 200 liters per hour at 43 psi, which is significantly more than the original 60-80 liters per hour flow rate of a standard pump . This extra capacity ensures your engine never runs lean, even under heavy load .

Maintenance Tips to Extend the Life of Your Fuel Pump

To extend the life of your 2004 Infiniti G35 Sedan fuel pump, you can implement several performance tips that focus on maintenance and driving habits :

1. Regularly replace the fuel filter. The general recommendation is to replace the fuel filter every 30,000 miles or as outlined in your owner's manual . A clogged filter can restrict fuel flow, leading to pump strain and potential failure .

2. Use high-quality fuel. Higher octane fuels generally contain detergents that help clean the engine and the fuel pump . Studies, including one by the American Petroleum Institute (API) in 2021, show that quality fuel can improve engine performance and increase fuel pump lifespan .

3. Avoid low fuel levels. Maintaining a higher fuel level can prevent the fuel pump from overheating, as the fuel acts as a coolant for the pump . Generally, it is advisable to refill when the gauge reads one-quarter of a tank .

4. Maintain a clean fuel system. Regular cleaning can involve using fuel system cleaners or having professional cleaning services performed at intervals recommended by the manufacturer .

5. Limit idling time. Excessive idling can strain the fuel pump, so consider shutting off the engine during extended stops .

6. Monitor for fuel leaks. Regular inspections for signs of leaks around fuel lines, connections, and the pump itself can help catch issues early .

7. Observe driving habits. Gentle acceleration and smoother driving can lessen strain on the fuel system, including the pump .

Cost Considerations

The cost of replacing the fuel pump on your 2004 Infiniti G35 Sedan can vary widely depending on several factors. The cost for a replacement can range from as low as $90 for a basic pump to over $1,400 for professional installation . Replacing a fuel pump in a G35 typically takes 2-4 hours, depending on experience and whether both pumps are being replaced . The cost of parts ranges from $200 to $400 per pump, with labor adding $150 to $300 if done professionally . DIYers can save significantly but should factor in tool rentals or purchases, such as a fuel pump module removal tool .

Top Recommendations for Your 2004 G35 Sedan Fuel Pump

When it comes to choosing the right fuel pump for your 2004 Infiniti G35 Sedan, you have several quality options. Here are our top recommendations:

1. OEM Infiniti Fuel Pump (17040-CD000) – This is the genuine factory part, guaranteeing a perfect fit and reliable performance. It is available from Infiniti parts dealers and is the safest choice if you want to maintain factory specifications .

2. Delphi Fuel Pump – Delphi is a trusted name in automotive fuel systems, and their in-tank electric fuel pump for the 2003-2006 Infiniti G35 Sedan is a popular aftermarket choice .

3. KEMSO Fuel Pump – If you want a high-performance upgrade with excellent value, KEMSO is the way to go.

Why You Should Choose KEMSO for Your 2004 Infiniti G35 Sedan Fuel Pump

When it comes to replacing your 2004 Infiniti G35 Sedan fuel pump, you have several options: OEM parts from the dealer, cheap no-name aftermarket pumps, or premium brands like KEMSO. Here's why KEMSO stands out as the best choice for American drivers.

High Performance, OEM Replacement. KEMSO fuel pumps are engineered as direct replacements for the original equipment, meaning they drop right into the factory location without modifications . But unlike the stock pump, KEMSO units are designed for superior flow and durability. They deliver up to 340 liters per hour at 43 psi, which is significantly more than the original 90-120 liters per hour flow rate of a standard pump . This extra capacity ensures your engine never runs lean, even under heavy load .

Lifetime Warranty. Every KEMSO fuel pump comes with a serialized body that guarantees a lifetime warranty . If it ever fails due to a manufacturing defect, KEMSO replaces it for free . This is a massive advantage over OEM and standard aftermarket parts, which typically have only a 1- or 2-year warranty .

Ethanol and E85 Compatible. With more gas stations switching to E15 or E85 blends, having a pump that resists ethanol degradation is essential . KEMSO's Viton-lined components prevent the swelling and cracking that destroy standard rubber seals . This makes them an excellent long-term investment for American drivers who want reliability and performance .

Unrivalled Quality Control. KEMSO operates a quality control program (ISO/TSO) and individually tests each pump before it leaves the factory . Many cheap aftermarket suppliers have little to no quality control, but KEMSO ensures every unit meets its performance specifications .

Complete Kit. When you buy a KEMSO fuel pump, you get everything you need for the installation: the pump, gradient density fuel strainers, flex hoses, Viton O-rings, wiring connectors, and clamps .

To learn more about KEMSO fuel pumps and find the right one for your 2004 Infiniti G35 Sedan, visit https://www.kemsoracing.com/. KEMSO offers high-performance fuel pumps for a wide range of vehicles, all backed by a lifetime warranty and rigorous quality testing. Whether you need a direct OEM replacement or a high-flow upgrade, KEMSO has you covered.

Conclusion

The 2004 Infiniti G35 Sedan fuel pump is a critical component that ensures your engine receives the proper fuel pressure for reliable performance. If you are experiencing symptoms like hard starting, sputtering, stalling, or a whining noise from the fuel tank area, it is time to replace your fuel pump . The replacement process is manageable for DIYers with basic mechanical skills, and there are several quality replacement options available . Whether you choose an OEM part or a high-performance aftermarket pump like KEMSO, addressing a failing fuel pump promptly will keep your G35 running smoothly for years to come. Remember to follow the maintenance tips outlined in this guide to extend the life of your new fuel pump, and consider upgrading to a high-performance option like KEMSO for improved reliability and peace of mind. For more information on high-quality fuel pumps with lifetime warranties, be sure to check out https://www.kemsoracing.com/.