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2016 Mazda 6 Hard Start and Fuel Pump Issues

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Kim L. · rep 0 · May 22, 4:49 AM · 1 replies · solved · Question

Vehicle: 2016 Mazda 6 Touring

My 2016 Mazda 6 Touring, with the 2.5L engine, has recently started having trouble starting, especially after it's been sitting for a few hours or overnight. It cranks for a long time, sometimes 5-10 seconds, before finally catching and starting up. Once it's running, it seems to drive fine.

I've heard about some fuel pump issues or recalls on certain Mazda models from around this era, and I'm wondering if that could be related to what I'm experiencing. There's no check engine light on, which makes it harder to diagnose.

Could this be a failing fuel pump, or is there something else I should be looking at? Any advice on how to confirm if it's a fuel delivery problem would be great.

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 4:49 AM

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ClearTheCode admin answer:

Hard starting, especially after the vehicle has been sitting, is a classic symptom of a fuel delivery issue. On your 2016 Mazda 6, it's definitely worth investigating the fuel system.

Here's what could be happening:

  1. Failing Fuel Pump: The fuel pump's job is to deliver fuel from the tank to the engine at the correct pressure. If the pump is weak or failing, it might struggle to build sufficient pressure, especially after the car has been off and fuel pressure has bled down. This leads to extended cranking. A common sign is a whining noise from the fuel tank area before starting.
  2. Leaky Fuel Injectors: If one or more fuel injectors are leaking, fuel pressure can drop quickly after the engine is shut off. This means the fuel pump has to work harder to re-pressurize the system during startup.
  3. Fuel Pressure Regulator: A faulty fuel pressure regulator can also cause pressure to bleed off too quickly, leading to hard starts.
  4. Fuel Filter: While less common on modern vehicles with long-life fuel filters, a severely clogged fuel filter could restrict fuel flow, making it harder for the pump to deliver adequate pressure.
  5. Check for Recalls: You are correct that some Mazda models from this period had fuel pump-related recalls. It's crucial to check if your specific VIN (Vehicle Identification Number) is affected by any open recalls. You can do this on the Mazda USA website or by calling a dealership.

Diagnostics & When to See a Shop:

The most definitive way to diagnose this is to perform a fuel pressure test. A mechanic will connect a gauge to the fuel rail and monitor the pressure during cranking and after the engine is shut off. They can see if the pressure is low or if it drops too quickly.

Since fuel system diagnostics can be complex and involve working with flammable liquids, it's highly recommended to take your Mazda 6 to a professional mechanic or a Mazda dealership. They have the proper tools and expertise to safely and accurately diagnose the issue, whether it's the fuel pump, regulator, or injectors, and address any potential recall-related repairs.

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