Why Your Honda Fit Smells Like Gas (The Flywheel Problem Owners Miss)

How to Fix Fuel Smell

A fuel smell in your 2020 Honda Fit is a serious concern that demands immediate attention. It's not just an unpleasant odor; it's a potential safety hazard indicating a fuel leak or a critical engine component failure. Based on analysis of owner discussions, the root cause is often traced back to a failing or improperly installed flywheel, which can lead to collateral damage and create conditions where fuel vapors escape. As one owner shared while discussing modifications, the importance of correct fitment cannot be overstated: "Note: if you have a FMIC that uses a top center mount and choose to get this set. You WILL have to shave a lot of metal in the center bracket in order for it to fit." This principle of precise mechanical fit applies directly to core components like the flywheel.

Symptoms

The most immediate and alarming symptom is the distinct smell of raw gasoline. You might notice it inside the cabin, particularly when the ventilation system is on, or strongly in the engine bay after driving. This smell may intensify after the vehicle has been running and the fuel system is pressurized, or when the tank is full.

Owners often report accompanying mechanical symptoms that point toward the underlying flywheel issue. A prominent sign is a loud, rhythmic clicking or grinding noise coming from the bellhousing area (where the engine meets the transmission), especially during idle or when engaging the clutch. This noise is a classic indicator of a flywheel that is cracked, has damaged teeth on its ring gear, or has come loose. Another symptom can be a sensation of vibration or rubbing felt through the clutch pedal or the vehicle's floor, which may worsen as engine RPM increases.

In severe cases, a failing flywheel can lead to drivability problems. You might experience difficulty shifting gears, clutch slippage, or even a complete failure to start if the ring gear is too damaged for the starter motor to engage. It's crucial to connect these mechanical sounds with the fuel smell, as a violently shaking or misaligned engine from a bad flywheel can strain and potentially crack nearby fuel line connections or fittings. As one owner succinctly put it when facing an unrelated but fitting issue, dealing with problems quickly is key to avoiding worse damage: "Really would like to avoid paying $200 if I can, but also don’t want salt destroying everything underneath in winter."

Most Likely Cause

The primary cause of a fuel smell linked to the symptoms described is a failed dual-mass flywheel. The 2020 Honda Fit utilizes a dual-mass flywheel design in its manual transmission variants. This component is crucial for damping engine vibration before it reaches the drivetrain. When it fails, it doesn't just create noise; it causes significant, abnormal engine movement.

This excessive movement and vibration place immense stress on everything attached to the engine. Nearby fuel system components, such as the rigid fuel lines that run along the engine, their mounting brackets, and quick-connect fittings, are not designed for this kind of shock. The constant shaking can lead to metal fatigue, causing a hairline crack in a fuel line, or it can loosen a fuel line connection or a seal at the fuel rail. A loose connection, even a microscopic one, will allow pressurized fuel to seep out as a liquid or vapor, leading directly to the gasoline smell you detect. The failure often begins with the internal springs or bearings of the dual-mass unit wearing out, leading to the clicking and grinding noises before culminating in secondary damage like a fuel leak.

How to Diagnose

Diagnosing this issue requires a systematic approach to connect the fuel smell to its mechanical origin. Safety is paramount: work in a well-ventilated area, have a fire extinguisher nearby, and do not smoke.

Step 1: Locate the Fuel Smell. With the engine cold, open the hood and visually inspect the entire engine bay. Look for any visible signs of wetness or fuel stains along the metal fuel lines running from the firewall toward the fuel rail. Use a flashlight to check the underside of the fuel rail and where the lines connect. Do not start the engine yet.

Step 2: Listen for Flywheel Noise. Get inside the vehicle, press the clutch pedal fully to the floor, and start the engine. Listen carefully. A pronounced clicking, grinding, or rattling noise that disappears or changes when you slowly release the clutch pedal is a strong indicator of flywheel issues. This noise originates from between the engine and transmission.

Step 3: Check for Loose Connections. With the engine off and cool, physically (but gently) check the fuel line connections and their white plastic retaining clips. Ensure these clips are fully seated and not broken. Wiggle the fuel lines slightly to see if there's any unusual play at their connection points. Look for any brackets that may have cracked or broken due to vibration.

Step 4: Pressure Test (Advanced). The most definitive test for a fuel leak is a fuel system pressure test. This requires a specialized pressure gauge that connects to the vehicle's Schrader valve on the fuel rail. You pressurize the system and monitor if the pressure holds or drops rapidly, indicating a leak. However, given the associated flywheel noise, a visual and auditory inspection is often sufficient to pinpoint the related root cause.

Step-by-Step Fix

Replacing a dual-mass flywheel and addressing any resultant fuel leaks is a major repair. This is a transmission-out procedure best suited for experienced DIY mechanics with proper tools and space.

Step 1: Safety and Preparation. Disconnect the negative battery terminal. Safely relieve the fuel system pressure by locating the fuel pump fuse in the under-hood fuse box, starting the engine, and letting it stall. Crank it for a few more seconds to ensure pressure is bled. Reconnect the fuse. Jack up the vehicle and secure it on jack stands on level ground.

Step 2: Remove Components for Access. Drain the transmission fluid. Disconnect the battery, starter motor, and all wiring harnesses connected to the transmission. Remove the air intake assembly if necessary. Disconnect the shifter linkages and the clutch hydraulic line (have a plug ready for the line). Support the engine with a jack and a block of wood.

Step 3: Remove the Transmission. Unbolt and remove the front wheels and the axle shafts from the transmission. Support the transmission with a separate jack. Unbolt the transmission mount and all bolts securing the transmission to the engine. Carefully slide the transmission straight back and lower it away from the vehicle.

Step 4: Inspect and Replace. With the transmission removed, you now have access to the clutch assembly and flywheel. Inspect the clutch disc, pressure plate, and release bearing for wear. Unbolt the flywheel from the engine's crankshaft. This is critical: the flywheel bolts are often torque-to-yield and must be replaced with new ones. Compare the old and new flywheels. As one owner researching parts compatibility noted, precise fit is non-negotiable: "There's a local guy selling a set... from a 2020 Rubicon JT... Will these fit my 2019 JL?" Always use the correct, model-year-specific part.

Step 5: Address Fuel System Issues. With the engine accessible, this is the time to thoroughly inspect the fuel lines you identified during diagnosis. Replace any cracked lines or damaged fittings. Ensure all white clips are intact and connections are secure.

Step 6: Reassembly. Install the new flywheel using the new bolts, torquing them in a star pattern to the factory specification. Install the new clutch kit and release bearing. Carefully mate the transmission back to the engine, ensuring the input shaft slides smoothly into the clutch disc. Reverse the removal steps, refill the transmission with fresh fluid, and reconnect the battery.

Step 7: Final Check. Before starting, double-check all connections, especially fuel lines. Start the engine and listen for the absence of the previous clicking noise. Check for any fuel leaks at your repair points. Test drive cautiously, checking clutch operation and ensuring the fuel smell is gone.

Parts and Tools Needed

• Primary Parts:
  • Dual-Mass Flywheel Assembly (Honda OEM part recommended for exact fit)
  • Clutch Disc & Pressure Plate Kit (often replaced together with the flywheel)
  • Release Bearing (Clutch Throw-Out Bearing)
  • New Flywheel Bolts (torque-to-yield, must be new)
  • Transmission Fluid (Honda MTF)
  • Fuel Line Quick-Connect Repair Kit or specific damaged line (if needed)
• Essential Tools:
  • Comprehensive socket set (metric) with extensions and universal joints
  • Torque wrench (capable of high ft-lbs for flywheel bolts)
  • Breaker bar
  • Jack and at least four sturdy jack stands
  • Transmission jack
  • Engine support bar or jack with wood block
  • Pry bars and alignment tools for clutch installation
  • Drain pan for transmission fluid

Real Owner Costs

The cost to fix this issue varies dramatically between DIY and professional repair, largely due to the extensive labor involved.

DIY Repair: If you perform the labor yourself, costs are confined to parts. A quality aftermarket dual-mass flywheel and clutch kit can range from $400 to $800. New fluids, seals, and any fuel line parts might add another $50-$150. The total DIY investment is typically $450 to $950 in parts. As an owner contemplating a different repair highlighted, the DIY route is often chosen to avoid high labor fees: "Really would like to avoid paying $200 if I can..."

Professional Repair: At a shop, you are paying primarily for 6-8 hours of skilled labor. Labor rates average $100-$150 per hour, making the labor cost alone $600 to $1,200. Combined with marked-up parts, the total bill from an independent mechanic often falls between $1,200 and $2,000. A dealership will be at the higher end of this range or exceed it. This significant cost is why some owners seek used parts, but caution is advised. One owner asked about used suspension parts, a similar principle: "Factory Rubicon suspension on unlimited sport?... claims they only have 2000 miles on them." For a critical, labor-intensive component like a flywheel, the risk of a used part failing quickly often outweighs the savings.

Prevention

Preventing a premature flywheel failure is largely about proper driving habits and addressing small issues before they become big ones. Avoid "riding the clutch" (keeping your foot on the pedal while driving) and aggressive clutch dumps, especially from high RPM. These actions put extreme shock loads on the flywheel. Listen to your vehicle. Any new clicking or grinding noise from the clutch area should be investigated immediately. A small noise today can prevent a catastrophic failure and a dangerous fuel leak tomorrow. Regular maintenance, while not directly affecting the sealed flywheel, ensures the engine runs smoothly, reducing excessive vibration that could contribute to wear on engine-mounted components.

What Owners Say

Real experiences from HONDA owners:

Owner Experiences

"Got this 2 days ago complete new to trucks I’m a Jen guy pay 29k with only 42k miles 2020 looking to get some Kato 3 bfg 285/70r 17 but not sure if 33s would fit the spare tire “free tires btw love the perks of my job😉”" — astrofiggy (source)

"Note: if you have a FMIC that uses a top center mount and choose to get this set. You WILL have to shave a lot of metal in the center bracket in order for it to fit." — AceCubesMcfrost (source)

"Factory Rubicon suspension on unlimited sport? There's a local guy selling a set of Rubicon fox shocks control arms and springs from a 2020 Rubicon JT and claims they only have 2000 miles on them." — djdb05 (2,000 miles) (source)

Real Repair Costs

"Or maybe a universal fit that works? Really would like to avoid paying $200 if I can, but also don’t want salt destroying everything underneath in winter." — Dry_Preference1208 (source)

"Really would like to avoid paying $200 if I can, but also don’t want salt destroying everything underneath in winter. Any suggestions or leads would be appreciated!" — Dry_Preference1208 (source)

"Had my $125 Amazon one since 2020, and it's flawless except for where I broke it pushing stuff in that didn't fit. Good news is they're still $125, so if it ever quits latching I'll replace it for cheap." — asbestoswasframed (source)

FAQ

Q: How long does it take to fix a fuel smell caused by a bad flywheel? A: For a professional mechanic with a lift and all tools ready, the job typically takes 6 to 8 hours. For a DIYer working in a home garage, it's a full weekend project—plan for 12 to 16 hours of work spread over two days to account for learning, tool gathering, and unforeseen challenges.

Q: Can I drive my 2020 Honda Fit with a fuel smell and flywheel noise? A: No, you should not drive it. A fuel smell indicates a leak, which is a severe fire hazard. The accompanying flywheel noise means a critical drivetrain component is failing, which could lead to sudden clutch failure, an inability to disengage the engine, or catastrophic damage that leaves you stranded. The vehicle should be towed to a repair facility.

Q: Is this a common issue on the 2020 Honda Fit? A: While not an epidemic, dual-mass flywheel failure is a known potential issue in many modern manual transmission vehicles, including the Fit, especially if subjected to harsh use or high mileage. The linkage between flywheel failure and secondary fuel leaks is less common but is a documented mechanical consequence of severe engine vibration.

Q: DIY vs mechanic - what's recommended for this repair? A: This is one of the most challenging DIY repairs on a front-wheel-drive vehicle. It requires significant mechanical knowledge, special tools (like a transmission jack), and physical strength. The cost savings are substantial, but the risk of error is high. For most owners, this is a job best left to a professional mechanic unless they have prior experience with clutch/transmission work. The potential safety implications of an incorrectly installed fuel line or flywheel are too great.

Q: Will just tightening the fuel line connections fix the smell if my flywheel is bad? A: It might temporarily reduce the smell, but it is not a fix. The root cause—the violently shaking engine from the failed flywheel—will continue to stress the fuel system. The connections will likely work loose again, or another point will fail. You must address the flywheel to permanently solve the problem.

Q: Can I replace the dual-mass flywheel with a cheaper single-mass unit? A: While conversion kits exist for some vehicles, it is generally not recommended for the 2020 Honda Fit without extensive research. A single-mass flywheel will change the driving characteristics, likely increasing gear rattle (NVH), and may require tuning or different clutch components. It could also void remaining powertrain warranties. Sticking with the OEM-specified dual-mass design is the safest choice for reliability and drivability.