Hi, here are some tests you can do to diagnose the problem. Please let me know if you have questions.
First, use a voltmeter or 12 volt test light to check for power on the red wire going to pin 8 of the ignition control module when the key is on. The module is in the left front corner of the engine compartment.
If there is no power, the problem is the ignition switch or EEC relay. If there is power, next, check the ignition coil as listed below.
IGNITION COIL TESTING
Primary and Secondary Circuit Tests
-
Turn the ignition switch
OFF
, disconnect the battery, then detach the wiring harness connector from the ignition coil to be tested.
-
Check for dirt, corrosion or damage on the terminals.
PRIMARY RESISTANCE
-
Use an ohmmeter to measure the resistance between the following terminals on the ignition coil, and note the resistance:
Except 2.3L, 2.5L and 5.0L engines
B+ to Coil 1
B+ to Coil 2
B+ to Coil 3
The resistance between all of these terminals should have
been between 0.3-1.0 ohms. If the resistance was more or less than this
value, the coil should be replaced with a new one.
SECONDARY RESISTANCE
Fig. Fig. 1: Engine ignition coil harness connections-3.0L and 4.0L engines
-
Measure, using the ohmmeter, and note the resistance between each
corresponding coil terminal and the two spark plug wire towers on the
ignition coil. The coil terminals and plug wires towers are grouped as
follows:
Except 2.3L, 2.5L and 5.0L engines
Terminal 3 (coil 1)-spark plugs 1 and 5
Terminal 2 (coil 3)-spark plugs 2 and 6
Terminal 1 (coil 2)-spark plugs 3 and 4If the coils test good, move on the the crankshaft sensor.
Using a DVOM set to the DC scale to monitor less than 5 volts,
measure the voltage between the sensor Cylinder Identification (CID)
terminal and ground by backprobing the sensor connector. If the
connector cannot be backprobed, fabricate or purchase a test harness.
The sensor is okay if the voltage reading varies more than 0.1 volt with
the engine running at varying RPM. (check both the blue and gray wires at the ignition module with the engine cranking.)
Fig. Fig. 3: CKP sensor wire harness connections for the 4.0L (VIN X and E) engines
If there is power and both the coils and sensor check good, replace the ignition control module.
×