Safety Warning

DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.

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HOMESERVICE MANUALSACURA2009MDXREPAIR AND DIAGNOSISENGINE PERFORMANCETUNE-UPIGNITION SYSTEMIGNITION TIMING INSPECTION

2009 Acura MDX

Ignition Timing Inspection

2009 Acura MDXSECTION Ignition Timing Inspection

Connect the Honda Diagnostic System (HDS) to the data link connector (DLC) (see step 2 on HOW TO USE THE HDS (HONDA DIAGNOSTIC SYSTEM) ).
Turn the ignition switch to ON (II).
Make sure the HDS communicates with the vehicle and the powertrain control module (PCM). If it doesn't communicate, troubleshoot the DLC circuit (see DLC CIRCUIT TROUBLESHOOTING ).
Check for DTCs. If a DTC is present, diagnose and repair the cause before inspecting the ignition timing.
Start the engine. Hold the engine at 3,000 rpm with no load (in P or N position) until the radiator fan comes on, then let it idle.
Check the idle speed (see IDLE SPEED INSPECTION ).
Jump the SCS line with the HDS.
Connect the timing light to the service loop.

Fig 1: Identifying Timing Light To Service Loop
Courtesy of AMERICAN HONDA MOTOR CO., INC.
Aim the light toward the pointer (A) on the timing belt cover. Check the ignition timing under a no load condition (headlights, blower fan, rear window defogger, and air conditioner are turned off).
Ignition Timing:

10° ± 2° BTDC (RED mark (B)) at idle in P or N position

Fig 2: Identifying Ignition Timing Mark
Courtesy of AMERICAN HONDA MOTOR CO., INC.
If the ignition timing differs from the specification, check the cam timing. If the cam timing is OK, update the PCM if it does not have the latest software (see PCM UPDATE ), or substitute a known-good PCM (see SUBSTITUTING THE PCM ), then recheck. If the ignition system works properly, replace the original PCM (see PCM REPLACEMENT ).
Disconnect the HDS and the timing light.

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.
• Brakes feel soft, pull hard to one side, or make grinding noises.
• The engine overheats, stalls repeatedly, or misfires under load.
• You are missing required tools, torque specs, or safe lifting equipment.
• You are not confident in the next step or safety outcome.