Ignition Timing: Testing and Inspection

Ignition Timing Inspection

Inspection

1. HDS DLC - Connection





1. Connect the HDS to the data link connector (DLC) (A) located under the driver's side of the dashboard.

2. Turn the ignition switch to ON (II).

3. Make sure the HDS communicates with the vehicle. If it does not communicate, go to the DLC circuit troubleshooting.

2. DTC - Check

1. Check for DTCs. If a DTC is present, diagnose and repair the cause before continuing with this test.

3. Warm Up The Engine

Start the engine. Hold the engine speed at 3,000 rpm without load in P or N until the radiator fan comes on, then let it idle.

4. Idle Speed - Inspection

1. Check the idle speed under no load conditions: headlights, blower fan, radiator fan, audio system, and air conditioner off.

Idle speed should be:

760±50 rpm (in P or N)

2. Let the engine idle for 1 minute with high electric load (A/C switch on, temperature set to max cool, blower fan on High, and headlights on high beam).

Idle speed should be:

760±50 rpm (in P or N)

NOTE: If the idle speed is not within specification, do the PCM idle learn procedure. If the idle speed is still not within specification, go to symptom troubleshooting.

5. Ignition Timing - Inspection





1. Jump the SCS line with the HDS.

2. Connect the timing light to the service loop (white tape).





3. Aim the light toward the pointer (A) on the cam chain case. Check the ignition timing under a no load condition (headlights, blower fan, rear window defogger, and air conditioner are turned off).







4. 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, or substitute a known-good PCM, then recheck. If the system works properly, and the PCM was substituted, replace the original PCM.

5. Disconnect the HDS and the timing light.