2005 Infiniti G35 Fuel Pump Location: Where It Is and How to Replace It Yourself

The bottom line: The fuel pump on a 2005 Infiniti G35 is located inside the fuel tank, and you can access it without dropping the tank. The main fuel pump assembly sits under the rear passenger-side seat cushion, accessed through a metal service panel on the floor. There is also a secondary fuel level sending unit under the driver-side rear seat. This location is the same for both the G35 sedan and coupe models from 2005 to 2008, and replacing the pump yourself is a manageable weekend job that can save you hundreds of dollars in labor costs.

Where Exactly Is the Fuel Pump Located?

The 2005 Infiniti G35 has a saddle-shaped fuel tank that straddles the driveshaft, which means it needs two separate fuel level sensors to give you an accurate reading. Here is exactly what you will find under your rear seats:

  • Main fuel pump assembly – located under the passenger-side rear seat cushion. This is the unit that delivers pressurized fuel to the engine. It includes the pump motor, fuel pressure regulator, fuel strainer (the "sock"), and the primary fuel level sending unit with its float arm.
  • Secondary fuel level sending unit – located under the driver-side rear seat cushion. This is only a sensor with a float arm. It does not contain a pump. Its job is to measure the fuel level on the other side of the saddle tank so your gauge reads correctly.

You do not need to drop the fuel tank to access either component. Both are reached by removing the rear seat bottom cushion and pulling off a black metal access cover. This is the single most important thing to know about the job: the tank stays in the car.

Symptoms of a Failing Fuel Pump in a 2005 G35

Before you start pulling seats, make sure the fuel pump is actually the problem. A bad fuel pump on a 2005 G35 typically shows these warning signs:

  • Engine cranks but will not start – This is the most common symptom. You turn the key, the starter spins the engine, but it never fires up.
  • Loss of power during acceleration – The car feels sluggish, especially when you step on the gas to merge onto a highway or climb a hill.
  • Engine sputtering or stalling – The car may hesitate or jerk while driving, and it might stall out at low speeds or when idling.
  • Whining noise from the rear passenger area – A healthy fuel pump makes a faint hum when you turn the key to the "ON" position. A loud, high-pitched whine coming from under the rear seat is a strong indicator that the pump is failing.
  • Poor fuel economy – If the pump is not maintaining proper pressure, the engine has to work harder, and your gas mileage will drop noticeably.

Keep in mind that a clogged fuel filter or a bad electrical connection can mimic a failing fuel pump. Have a shop run a fuel pressure test before you buy parts. If the pressure at the fuel rail is below the factory specification of roughly 50-55 psi, the pump is likely the culprit.

How to Access the Fuel Pump: Step-by-Step

The job is rated as a 2 out of 5 in terms of difficulty. Plan for about 1.5 to 3 hours if you are doing it yourself.

Safety First

Fuel is extremely flammable. Work in a well-ventilated area, keep a fire extinguisher nearby, and disconnect the negative battery terminal before you do anything else.

Step 1: Relieve Fuel System Pressure

Locate the fuel pump fuse in the fuse box (usually under the dash or in the engine bay). Pull the fuse, then start the engine. The engine will run for a few seconds and then stall. Crank the engine for another 3-5 seconds to clear any remaining pressure in the fuel lines.

Step 2: Remove the Rear Seat Cushion

The rear seat bottom cushion is held in by two clips at the front edge. Firmly pull up on the front of the cushion to pop it free. It may require a good amount of force, but be careful not to tear the upholstery or break the plastic clips. Once it is loose, lift the cushion out of the car.

Step 3: Remove the Access Cover

With the seat cushion out, you will see two black metal plates on the floor. The larger one on the passenger side covers the fuel pump. The smaller one on the driver side covers the secondary sending unit. Use a Phillips screwdriver to remove the four screws holding the passenger-side plate. Set the plate aside.

Step 4: Disconnect Everything

Before you unbolt the pump assembly, clean all dirt and debris from around the access opening so nothing falls into the fuel tank. You will see the top of the fuel pump module with an electrical connector and a fuel line.

  • Disconnect the electrical connector by pressing the release tab and pulling it apart.
  • Disconnect the fuel supply line by pressing the release tabs on the quick-disconnect fitting. Have a rag ready to catch any small amount of residual fuel that drips out.

Step 5: Unbolt and Remove the Old Pump

The fuel pump assembly is held to the tank by either six or eight 8mm bolts. Remove them all with a socket and ratchet. Carefully lift the assembly straight out of the tank. You may need to tilt it slightly to get the float arm through the opening. Be gentle—the plastic housing and the float arm are fragile.

Step 6: Install the New Pump

  • If you bought a complete assembly: Installation is the reverse of removal. Place the new pump assembly into the tank, making sure the float arm is oriented correctly so it does not hit the sides of the tank. Tighten the 8mm bolts in a star pattern to ensure an even seal. Always replace the large rubber O-ring that seals the assembly to the tank. A worn O-ring can cause fuel leaks and fumes inside your car.
  • If you bought just the pump motor: You will need to disassemble the plastic housing to swap the pump. This is cheaper but more involved. Carefully remove the pump retainer, pull out the old pump, and install the new one using all three O-rings on the pump outlet. You typically do not reuse the old rubber grommet. Reassemble the housing and install it in the tank.

Step 7: Reconnect and Test

Reconnect the fuel line (push it on until you hear a click). Plug in the electrical connector. Reinstall the access cover and the rear seat cushion. Reconnect the negative battery terminal and reinstall the fuel pump fuse. Turn the ignition to the "ON" position for 2 seconds, then turn it off. Repeat this cycle 3 times to prime the fuel system. Start the engine and check for fuel leaks at the connection points.

Cost of a 2005 G35 Fuel Pump Replacement

Prices vary dramatically depending on where you buy the part and whether you do the work yourself.

  • New OEM from a dealer: $500 to over $1,400. Expensive, but guaranteed fit and quality.
  • New aftermarket (OEM-quality brands like Hitachi or Delphi): $250 to $400. These offer a good balance of quality and price.
  • New aftermarket (budget brands): $60 to $150. Lower upfront cost, but forum reports suggest a higher risk of noise and premature failure.
  • Used OEM from a recycler: $50 to $125. A cost-effective option if you can verify the mileage and condition of the donor pump. A pump with over 100,000 miles is nearing the end of its service life.
  • Shop labor: $110 to $250, typically for 1 to 1.5 hours of labor.

If you have a shop do the whole job, RepairPal estimates an average total cost between $1,332 and $1,384 for a 2005 G35.

Common Mistakes to Avoid

  • Bending the float arm – The float arm is delicate. If you bend it during removal or installation, your fuel gauge will read incorrectly. Handle the assembly carefully.
  • Forgetting the secondary sender – If your fuel gauge is still wrong after replacing the pump, the driver-side secondary sending unit is likely also faulty. It needs to be cleaned or replaced.
  • Using a cheap aftermarket pump – Low-cost pumps are notorious for premature failure and incorrect sending unit resistance values, which cause persistent fuel gauge errors. You end up doing the job twice.
  • Skipping the O-ring replacement – Always install a new O-ring on the tank flange. Old O-rings harden and shrink over time, leading to fuel vapor smells inside the cabin.

Compatibility Question: Will a Nissan 350Z Fuel Pump Fit?

The 2005 G35 and the Nissan 350Z share the same VQ35DE engine platform, and their fuel systems are very similar. For corresponding model years (e.g., a 2005 350Z pump for a 2005 G35 Coupe), the pump assembly is often identical. However, you must verify the part number and visually confirm that the electrical connector and hose ports match before you buy. Subtle differences exist between coupe and sedan models and between VQ35DE and VQ35HR engine variants.

Which Fuel Pump Should You Buy?

You have several solid options for a 2005 G35 fuel pump replacement. If you want a direct OEM replacement with proven quality, brands like Hitachi (an OEM supplier) and Delphi are excellent choices in the $250-$400 range. If you are on a tight budget, a used OEM pump from a low-mileage donor car (under 100,000 miles) is a smart option at $50-$125.

For owners who want a brand-new, high-performance pump that comes with a lifetime warranty and superior ethanol resistance, a premium aftermarket option is worth considering.

Why Choose KEMSO Fuel Pump for Your 2005 Infiniti G35

When you are ready to replace the fuel pump on your 2005 G35, KEMSO offers a compelling alternative to both expensive OEM parts and unreliable budget pumps.

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, delivering up to 200 liters per hour at 43 psi—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. KEMSO stands behind its product for as long as you own the pump.

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.

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. No running back to the auto parts store for missing pieces.

Visit https://www.kemsoracing.com/ to check their product lineup for the 2005 Infiniti G35 and see why G35 owners choose KEMSO for a reliable, long-lasting fuel pump replacement.

Final Checklist for the Job

  • Tools you will need: Socket set with 8mm socket, Phillips screwdriver, needle-nose pliers, clean rags, a fuel-safe container, and a fuel line disconnect tool (optional but helpful).
  • Parts you will need: New fuel pump assembly (or just the pump motor), new O-ring for the tank flange, and new fuel strainer if not included.
  • Time estimate: 1.5 to 3 hours for a first-timer.
  • Safety reminders: Work outdoors or with the garage door open. Disconnect the battery. Keep a fire extinguisher within reach. Do not smoke or use any open flame near the work area.

For more information and to find the right fuel pump for your 2005 Infiniti G35, visit https://www.kemsoracing.com/.


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