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Intermittent Hard Start and Fuel Smell on 2016 LaCrosse 3.6L

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Chris P. · rep 0 · May 22, 3:49 AM · 1 replies · solved · Question

Vehicle: 2016 Buick LaCrosse Premium

Hey everyone, I've got a puzzling issue with my 2016 Buick LaCrosse, 3.6L V6. Lately, it's been having intermittent hard starts, especially after sitting for a few hours. It cranks for a bit longer than usual before finally firing up. Sometimes, I also notice a faint smell of fuel around the car, particularly after one of these hard starts.

There's no check engine light on yet, which is making it harder to diagnose. I'm wondering if this could be a fuel pressure issue or something related to the fuel system. Has anyone with a similar LaCrosse experienced this, and what was the fix? I'm trying to avoid a costly diagnostic if it's a known problem.

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 3:49 AM

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ClearTheCode admin answer:

Intermittent hard starts and a fuel smell on your 2016 Buick LaCrosse 3.6L V6, even without a check engine light, strongly suggest an issue within the fuel delivery system. This is a problem that should be investigated promptly due to the potential fire hazard associated with fuel leaks.

Common Causes & Diagnostics:

  1. Leaking Fuel Injector: A fuel injector that isn't sealing properly can leak fuel into the cylinder after the engine is shut off. This causes a 'flooded' condition for that cylinder, leading to hard starts. The fuel smell would be from unburnt fuel in the exhaust or engine bay.
  2. Fuel Pressure Regulator Failure: If the fuel pressure regulator is faulty, it might not maintain residual fuel pressure in the system after the engine is off. This means the fuel pump has to work harder to re-pressurize the system during startup, leading to extended cranking.
  3. Fuel Pump Check Valve Failure: Similar to the regulator, a failing check valve within the fuel pump assembly can allow fuel pressure to bleed off when the engine is off, causing hard starts.
  4. Evaporative Emission (EVAP) System Leak: While less likely to cause a hard start without a CEL, a significant leak in the EVAP system (e.g., a cracked hose, faulty purge valve, or loose gas cap) could allow fuel vapors to escape, causing a smell. However, this usually triggers codes like P0440, P0442, P0455.
  5. High-Pressure Fuel Pump (HPFP) Issues (if applicable): On direct injection engines, the HPFP can sometimes fail to build pressure quickly enough, leading to hard starts. However, this often triggers specific fuel pressure codes.

When to See a Shop:

  • Immediately: If the fuel smell becomes strong, or if you see any visible fuel leaks. This is a safety concern.
  • Soon: If the hard starts become more frequent or if a check engine light eventually illuminates. A professional technician can perform a fuel pressure test (both static and dynamic), inspect for fuel leaks, and check injector performance to accurately diagnose the problem. Addressing this early can prevent more serious issues and ensure your vehicle's safety.
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