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2017 MDX Oil Consumption and Misfires - VCM Issue?

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Mike T. · rep 0 · May 22, 4:55 AM · 1 replies · solved · Question

Vehicle: 2017 Acura MDX Advance

Hi everyone,

I own a 2017 Acura MDX Advance with about 90,000 miles, and I've been noticing a couple of concerning issues lately. First, the oil consumption has increased significantly. I find myself adding a quart of oil every 1,500-2,000 miles, which seems excessive. Second, I've started to experience occasional misfires, especially at idle or low speeds, and sometimes a slight vibration when cruising on the highway.

I've read online about Acura's Variable Cylinder Management (VCM) system causing similar problems, leading to fouled spark plugs and even piston ring issues. Could this be what's happening to my MDX? Has anyone had success with a VCM disabler or other fixes?

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 4:55 AM

0

ClearTheCode admin answer:

Excessive oil consumption and misfires in a 2017 Acura MDX are indeed commonly linked to the Variable Cylinder Management (VCM) system. Here's a breakdown of the causes and potential solutions:

  1. VCM Operation: VCM deactivates cylinders (typically 3 of 6) during light load cruising to improve fuel economy. This can lead to uneven wear on piston rings in the deactivated cylinders due to lack of combustion and lubrication, causing oil to bypass the rings and burn off.
  2. Fouled Spark Plugs: The burning oil can foul spark plugs in the deactivated cylinders, leading to misfires (which might trigger codes like P0301, P0302, P0303, etc., for specific cylinder misfires).
  3. Carbon Buildup: Prolonged VCM operation can also contribute to carbon buildup on valves and piston crowns, further exacerbating oil consumption and misfire issues.
  4. Engine Mounts: The vibration you feel on the highway can sometimes be related to VCM, as the engine runs on fewer cylinders, causing different harmonics. Worn engine mounts can also amplify this.

Solutions and When to See a Shop:

  • VCM Disabler: Many owners opt for a VCM disabler module (e.g., VCMuzzler, S-VCM Controller) which tricks the ECU into thinking the engine is always under load, preventing cylinder deactivation. This can significantly reduce oil consumption and misfires, but it's an aftermarket solution.
  • Spark Plug Replacement: If misfires are present, replacing the spark plugs, especially in the affected cylinders, is a good first step. Use OEM-specified plugs.
  • Piston Ring Service: In severe cases of oil consumption, the only permanent fix might be a piston ring replacement, which is a major engine repair.
  • Regular Oil Changes: Ensure you're using the correct oil viscosity and performing regular oil changes to monitor consumption.

When to see a shop:

  • Promptly if the check engine light is flashing (indicating active misfires that could damage the catalytic converter).
  • If oil consumption is rapidly increasing or if you're adding more than a quart every 1,000 miles.
  • For a professional diagnosis to confirm VCM-related issues and discuss repair options, including potential warranty coverage if applicable (though less likely at 90k miles).
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