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Home >> Mazda >> 2014 >> MX-5 Miata Club, Automatic Trans >> Repair and Diagnosis >> Engine Performance >> System >> Symptom Troubleshooting [Engine Control System] >> Engine Control System Operation Inspection >> Spark Test
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Spark Test

  1. Disconnect the fuel pump relay.
  2. Verify that each ignition coil and connector is connected properly.
  3. Inspect the ignition system in the following procedure.
    WARNING:
    • High voltage in the ignition system can cause strong electrical shock which can result in serious injury. Avoid direct contact to the vehicle body during the following spark test.
STEP INSPECTION ACTION
1
  • Disconnect the ignition coil from spark plugs.
  • Remove the spark plugs.

    (See SPARK PLUG REMOVAL/INSTALLATION ).

    • Verify that the spark plugs do not have carbon deposits.
  • Are the spark plugs normal?
Yes Go to the next step.
No Perform no-load racing at 4, 000 rpm  for 2 min, 2 times  to burn off the carbon deposits.
Repeat Step 1.
2
  • Inspect the spark plugs for damage, wear, and proper plug gap.
  • Are the spark plugs normal?
Yes Go to the next step.
No Replace spark plugs, then go to the next step.
(See SPARK PLUG REMOVAL/INSTALLATION ).
3
  • Reconnect the spark plugs to the ignition coil.
  • Ground the spark plugs to the engine.
  • Is a strong blue spark visible at each cylinder while cranking the engine?
Yes Ignition system is normal.
No Some cylinders do not spark: 
  • Go to the next step.

All cylinders do not spark: 
  • Go to Step 5.
4
  • Inspect the following wiring harnesses for open or short
    • Ignition coil No. 1 terminal C-PCM terminal 2BA
    • Ignition coil No. 2 terminal C-PCM terminal 2AW
    • Ignition coil No. 3 terminal C-PCM terminal 2AX
    • ignition coil No. 4 terminal C-PCM terminal 2AT
  • Are the wiring harnesses normal?
Yes Inspect and replace the ignition coil.
(See IGNITION COIL INSPECTION ).
(See IGNITION COIL REMOVAL/INSTALLATION ).
No Repair or replace the malfunctioning part, then go to Step 1.
5
  • Turn the ignition switch to ON.
  • Measure the voltage at terminal A in each ignition coils.
  • Is the voltage B+?
Yes Go to the next step.
No Inspect the power supply circuit of ignition coils.
6
  • Verify continuity between each ignition coils terminal B and battery negative terminal.
  • Is there any continuity?
Yes Go to the next step.
No Inspect the ground circuit of ignition coils.
7
  • Does the PCM connector or ignition coil connectors have poor connection?
Yes Repair or replace the connector, then go to Step 1.
No Go to the next step.
8
  • Inspect the CKP sensor and crankshaft pulley.
  • Are the CKP sensor and crankshaft pulley normal?
Yes Inspect for open or short circuit in wiring harness and connector of CKP sensor.
No Repair or replace the malfunctioning part, then go to Step 1.