Refer to Engine Controls Schematics .
Circuit Description
The secondary ignition check tests for faulty spark plugs, plug wires, or IC module and coils. This table requires the J 26792 spark tester (ST125).
Test Description
Numbers below refer to the step numbers on the Diagnostic Table:
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The J 26792 spark tester presents a more difficult load on the secondary ignition than a normal spark plug. If a miss, stumble, or hesitation is being caused by a spark plug not firing, the spark tester should also not fire.
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Use a 5% saltwater solution in a spray bottle to induce voltage arching to ground through faulty insulation of spark plug wires.
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If the no spark condition follows the suspected coil, that coil is faulty. Otherwise, the ignition module is the cause of no spark. This test could also be performed by substituting a known good coil for the one causing the no spark condition.
Step | Action | Value(s) | Yes | No | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | Did you perform the Powertrain On Board Diagnostic (OBD) System Check? | -- | ||||||||||
2 |
Does the scan tool indicate 3X reference signal present? | -- | ||||||||||
Did you observe any non-sparking cylinders? | -- | |||||||||||
Inspect and test the affected cylinder spark plug wire(s), Ignition coil(s), and Spark plugs for a short to ground or arching to ground. If Carbon tracking or corrosion is present, replace both components affected. Refer to Spark Plug Wire Harness Replacement in Engine Electrical, Ignition Coil Replacement in Engine Controls, Spark Plug Replacement in Engine Electrical. Did you find and correct the condition? | -- | |||||||||||
5 | Test affected spark plug wire(s) for proper resistance. Replace spark plug wire(s) not near specification. Refer to Spark Plug Wire Harness Replacement in Engine Electrical. Did you find and correct the condition? | 600ohms per ft (1,968ohms per M) | ||||||||||
Switch the affected cylinder coil with a known good one. If the fault follows the affected coil replace it. Refer to Ignition Coil Replacement in Engine Controls. Did you find and correct the condition? | -- | |||||||||||
7 | Inspect the spark plug wires for proper routing and for the correct firing order. If any spark plug wires are found to be misrouted, reroute as necessary. Refer to Spark Plug Wire Harness Replacement in Engine Electrical. Did you find and correct the condition? | -- | ||||||||||
8 | With a DMM, Check spark plugs for internal short to ground. Replace any grounded Spark plugs found. Refer to Spark Plug Replacement in Engine Electrical. Did you find and correct the condition? | -- | ||||||||||
9 |
If any spark plugs are found to be bad, replace the affected spark plugs. Refer to Spark Plug Replacement in Engine Electrical. Did you complete the replacement? | -- | -- | |||||||||
10 |
Does the test lamp light? | -- | ||||||||||
11 | Connect a test lamp between the IC Module ignition feed circuit and IC Module ground circuit. Does the test lamp light? | -- | ||||||||||
12 |
Does the DMM indicate AC Duty Cycle present? | -- | ||||||||||
13 | Test the 7X Crank Sensor circuits for the following conditions:
Repair any damaged wiring. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | ||||||||||
14 | Repair the open or short to ground in the IC Module Ignition feed circuit. Refer to Wiring Repairs in Wiring Systems. Replace the fuse if necessary. Did you complete the repair? | -- | -- | |||||||||
15 | Repair the open in the IC Module ground circuit. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |||||||||
16 | Replace IC Module. Refer to Ignition Coil Replacement in Engine Controls. Did you complete the replacement? | -- | -- | |||||||||
17 | Replace the 7X Crank Sensor. Refer to Crankshaft Position Sensor Replacement in Engine Controls. Did you complete the replacement? | -- | -- |
