2004 Infiniti G35 Fuel Pump Location: How to Find, Diagnose, and Replace It Yourself
If you own a 2004 Infiniti G35 and your engine cranks but won't start, or if the car stalls unexpectedly, the fuel pump is likely the problem. The main fuel pump on a 2004 Infiniti G35 is located inside the fuel tank, underneath the rear passenger-side seat cushion. You do not need to drop the fuel tank to access it. Simply remove the rear seat bottom and the metal access cover to reach the pump assembly. This guide walks you through exactly where to find it, how to confirm it's failing, and what to do next.
Understanding the 2004 G35 Fuel Pump System
The 2004 Infiniti G35 uses a dual fuel pump system because of its saddle-shaped fuel tank. This design allows the car to deliver consistent fuel pressure even during hard cornering and spirited driving.
Main pump location: Under the rear passenger-side seat cushion. This is the primary pump that sends fuel to the engine.
Secondary sender location: Under the rear driver-side seat cushion. This unit is only a fuel level sensor; it does not contain a pump. The G35 needs two sensors to accurately read fuel level across the saddle tank.
Most of the time, you only need to replace the main pump, as it is unlikely that both units fail at the same time. If your fuel gauge is acting up but the car runs fine, the issue might be the driver-side sending unit, not the pump itself.
Common Symptoms of a Failing Fuel Pump
Before you start digging into the rear seat, confirm that the fuel pump is actually the problem. Here are the most common signs G35 owners report:
1. Engine sputters or stalls at high speeds
The fuel pump cannot keep up with demand, so the car hesitates or jerks, especially under load or on the highway.
2. Loss of power during acceleration
A weak pump means low fuel pressure to the injectors, resulting in sluggish performance when you step on the gas.
3. Difficulty starting the engine
The engine cranks for a long time before firing up, or it may not start at all. This happens when the pump cannot build adequate pressure quickly.
4. Loud whining noise from the fuel tank area
A healthy pump makes a quiet hum for a few seconds when you turn the key to "ON." A high-pitched whine or constant loud noise means the pump is wearing out.
5. Check Engine Light
Faulty pumps can trigger diagnostic trouble codes related to fuel system pressure, such as P0462 or P0463, which indicate a fuel level sensor or pump circuit problem.
How to Access the 2004 Infiniti G35 Fuel Pump
Getting to the fuel pump on a 2004 G35 is a straightforward DIY job rated about 2.5 out of 5 in difficulty. You will need basic hand tools, a rag for spills, and about 2 to 4 hours of time.
Tools you will need:
- Socket set (8mm socket is typically needed for the pump retaining bolts)
- Phillips screwdriver
- Needle-nose pliers
- A rag or shop towel
- A fuel-safe container for any spills
- Safety glasses and gloves
Step-by-step access procedure:
Step 1: Relieve fuel system pressure
Locate the fuel pump fuse in the fuse box (usually under the dash or in the engine bay). Remove the fuse, then start the engine and let it run until it stalls. Crank the engine two or three more times to clear any remaining pressure. Turn the ignition off.
Step 2: Disconnect the battery
Remove the negative battery terminal. This is a critical safety step to prevent sparks near the fuel system.
Step 3: Remove the rear seat cushion
The rear seat bottom is held in by wire hooks. Pull up firmly on the front edge of the seat cushion to release it, then pull the seat forward to remove it.
Step 4: Remove the access cover
On the passenger side floor pan, you will see a round or rectangular metal access panel. It is typically held in place by four Phillips screws or plastic clips. Remove the screws or rotate the clips 90 degrees, then lift the panel off.
Step 5: Disconnect wiring and fuel lines
You will see the top of the fuel pump assembly. Clean any dirt or debris from around the cover before opening it. Disconnect the electrical harness from the top of the pump. Then, use a rag to catch any fuel spillage and disconnect the quick-disconnect fuel line. The fuel line typically has a push-button release.
Step 6: Remove the pump assembly
Use an 8mm socket to unscrew the retaining bolts (usually 6 or 8 of them). Carefully lift the pump assembly straight out of the tank. Be careful not to bend the float arm or snag it on wires inside the tank. The tank will still contain some fuel, so have your rag or container ready.
Replacing the Fuel Pump: Install Tips
Use a new O-ring seal
It is highly recommended to replace the large rubber O-ring that seals the pump assembly to the tank. This prevents fuel leaks and fumes inside the cabin.
Transfer components carefully
If you are replacing just the pump motor inside the plastic housing (instead of the whole assembly), you will need to disassemble the unit. This is a cheaper but more involved process. For most DIYers, replacing the entire assembly is faster and ensures the fuel pressure regulator and sending unit are fresh.
Prime the system before starting
After installing the new pump, reconnect the battery and install the fuel pump fuse. Turn the ignition to the "ON" position for 2 seconds, then turn it off. Repeat this three times to prime the fuel system. Check for any leaks at the connections before starting the engine.
Cost of Replacement
The cost to replace the fuel pump on a 2004 Infiniti G35 varies significantly based on the part source.
- New OEM (Dealer): $650 to $1,400+
- New OEM (Online): $420 to $560
- New Aftermarket: $65 to $325
- Used OEM: $50 to $150
- Shop Labor: $110 to $200
For the 2004 G35, the OEM part number for the complete fuel pump assembly is typically 17040-EJ81A or 17040-JK60A. The stock pump delivers about 90 to 120 liters per hour (LPH).
Why You Should Choose KEMSO for Your 2004 Infiniti G35 Fuel Pump
When it comes time to replace your fuel pump, you have several choices: expensive dealer OEM parts, cheap no-name aftermarket pumps, or a premium brand like KEMSO. Here is why KEMSO stands out as the best option for your G35.
High Performance, OEM Replacement
KEMSO fuel pumps are engineered as direct replacements for the original equipment. They drop right into the factory location without any modifications. Unlike the stock pump, KEMSO units are designed for superior flow and durability. They 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.
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.
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 find the right KEMSO fuel pump for your 2004 Infiniti G35, visit:
https://www.kemsoracing.com/
Extending the Life of Your G35 Fuel Pump
Once you have a new pump installed, you can take steps to make it last as long as possible.
Avoid low fuel levels
Keep the tank above a quarter full. The fuel acts as a coolant for the pump. When the tank is frequently low, the pump can overheat and wear out faster.
Replace the fuel filter regularly
The G35's fuel filter is a cartridge-style filter attached to the pump assembly inside the tank. It should be replaced every 30,000 to 36,000 miles or whenever you replace the pump.
Use high-quality fuel
Higher octane fuels generally contain detergents that help clean the engine and the fuel system. Quality fuel can improve engine performance and increase fuel pump lifespan.
Limit aggressive driving habits
Aggressive acceleration demands more from the fuel pump. Smooth, gentle driving reduces strain on the fuel system.
Final Thoughts
The 2004 Infiniti G35 fuel pump is located under the rear passenger-side seat, and accessing it is a manageable DIY job for anyone comfortable with basic tools. If you are experiencing stalling, hard starting, or a whining noise from the rear, the pump is very likely failing. Replacing it promptly prevents being stranded and avoids potential engine damage from low fuel pressure.
For the best combination of performance, reliability, and value, consider a KEMSO fuel pump. With up to 200 LPH flow, a lifetime warranty, and ethanol compatibility, it is a smart upgrade for any G35 owner looking to keep their car running strong.
Find your KEMSO fuel pump at: https://www.kemsoracing.com/