1989 Ford Thunderbird SC

If there are any codes, trouble shoot those first.  If no Codes, continue.

Use a Spark Tester to check for spark at all spark plug wires while cranking

If there was spark present on ALL spark plug wires and they were consistent (one spark per crankshaft revolution), go to N3 otherwise go to N5

Connect a LED Test Lamp between (+) Pin 1 on the Crankshaft sensor and the battery (-) negative lead.

Crank the engine

If the LED Test :Lamp blinks continuously during the Crank go to N4.  Otherwise replace the crankshaft sensor.

Remove the EEC-IV from the vehicle harness connector.

Remove both connectors from the DIS.

Measure resistance between pin 56 of the EEC-IV harness connector and Pin 1 of the connector to the Crankshaft Sensor.

Also measure the resistance between Pin 16 of the EEC-IV harness connector and Pin 3 of the Crankshaft Sensor (IGND PS).

If both measurements are less than 5 then go to basic troubleshooting... Lack of fuel bad spark plugs.  If not, check for problems in the connectors or a problem with damage to a wire.

Was spark missing from BOTH cylinder 1 and 5 plug wires?
or
Was spark missing from BOTH cylinder 2 and 6 plug wires?
or
Was spark missing from BOTH cylinder 3 and 4 plug wires?

If so, then go to N7  Otherwise go to N6

Check spark plug wires for damage. Remove and check spark plugs for damage or wear and proper gap.

If spark plug wires and plugs are O.K. go to N7 otherwise repair the plugs/wires and retest.

Reconnect all cables.

Connect LED test lamp between (-) Pin 7 (IGNG D) and (+) Pin 1 (VBAT D). 

Turn the Key on

If the LED Test lamp is on, go to N8  otherwise check the connectors and service or replace the harness.

Key off

Measure resistance between (-) Negative Battery connection and Pin 7 on the DIS.

If the resistance is less than 5 ohms, go to N10 otherwise go to N9

Check if the DIS module mounting screws are corroded or loose.  Pay particular attention to the bottom ones.

If the screws are clean and tight, replace the DIS module and rerun the test.  Otherwise clean and tighten the screws. Don't forget the heat sink compound.

Key on

Connect LED Test Lamp between three pairs of test points.  Note if lamp is on or off each time.

Check between (+) Pin 8 on the DIS connector and the Negative Battery Cable.

Check between (+) Pin 11 on the DIS connector and the Negative Battery Cable.

Check between (+) Pin 9 on the DIS connector and the Negative battery cable.

If the LED test lamp was on for all three checks, go to N15, otherwise go to N11

Key off.

Disconnect the Pins 7 thru 12 connector from the DIS.

Connect a jumper wire between Pin 7 on the DIS (IGND D) and Negative Battery cable.

Repeat the tests in Step N10.

If the LED Test lamp was now on for all three checks, Replace the DIS Module.  Otherwise remove the jumper wire and go to N12

Key off

Reconnect cables to DIS

Connect LED Test lamp between (+) Pin 4 on the coil pack (VBAT C) and Negative cable on the battery.

Key On.

If the LED Test lamp is on, go to N13, otherwise check the connectors and service or replace the harness.

Key On

Connect the LED Test lamp between three pairs of locations given below.  Note if the LED test lamp is on or off for each one.

__ Check between (+) Pin 1 of the Coil Pack connector (C2C) and Negative Battery Cable (-)

__ Check between (+) Pin 2 of the Coil Pack connector (C3C) and Negative Battery Cable (-)

__ Check between (+) Pin 3 of the Coil Pack connector (C1C) and Negative Battery Cable (-)

If the LED Test lamp was on for all three checks, then check all connectors and service or replace the harness.  Otherwise go to N14

Disconnect connector from the Coil Pack

Key off

Connect a jumper between Positive Battery Cable (VBAT +) and Pin 4 on the Coil Pack connector (VBAT C).

Repeat test procedure in Test Step N13

If the LED Test Lamp was now on for all three checks, Remove the jumper wire and check connectors and service or replace the harness, otherwise Remove the jumper wire and replace the Coil Pack.  Rerun the tests.

Connect LED Test Lamp between (+) Pin 4 of the DIS connector (PIP D) and (-) Negative Battery Cable

If the LED Test lamp blinks when the engine is cranked go to N16 otherwise go to N22.

Connect LED Test lamp between (+) (SPOUT) and (-) Negative battery cable

If the LED Test Lamp blinks when the engine is cranked, go to N17, otherwise go to N19

Connect a LED Test Lamp between each of three pairs of test points.  Note if lamp blinks continuously for each during crank.

__ Check between (+) Pin 8 of DIS (C1D) and (-) Negative Battery Cable.

__ Check between (+) Pin 11 of DIS (C2D) and (-) Negative Battery Cable.

__ Check between (+) Pin 9 of DIS (C3D) and (-) Negative Battery Cable.

If the LED Test lamp blinks during all three checks, Replace the Coil Pack and rerun tests.  Otherwise Go to N18.

Disconnect Connector from Coil Pack.

Key off

Connected the LED Test lamp between each of three pairs of test points given.  Note if the lamp is on for each one with Key On.

__ Check between (+) Pin 8 of DIS (C1D) and (-) Negative Battery Cable.

__ Check between (+) Pin 11 of DIS (C2D) and (-) Negative Battery Cable.

__ Check between (+) Pin 9 of DIS (C3D) and (-) Negative Battery Cable.

If any LED Test lamp was on, Check the connectors and service or replace the harness.  If not, Replace the DIS module and rerun the tests.

Key off

Disconnect EEC-IV processor

Connect the LED Test lamp between (+) Pin 5 on the DIS Connector  (SPOUT) and (-) Negative Battery cable.

If the LED Test Lamp blinks continuously while the engine is cranked, the EEC Processor is shorting the SPOUT, replace it.  Otherwise go to N20

Disconnect connector from DIS Module Pins 1-6.

Key off

Connect LED Test Lamp between (+) Pin 5 on the DIS connector (SPOUT) and the (-) Negative battery cable.

Key on

If the LED Test lamp is on, the SPOUT is shorted to the battery. Check connectors and service or replace the harness.  Otherwise go to N21

Connect LED Test Lamp between (-) Pin 5 on the DIS connector (SPOUT) to the Positive battery cable connector.

Key on

If the LED Test lamp is on, the SPOUT is shorted to ground, check the connectors and service or replace the harness.  If the LED Test lamp is not on, replace the DIS module and rerun the test.

Key off

Disconnect DIS Connector to Pins 1-6.

Connect LED Test Lamp between (+) Pin 4 on the DIS Connector (PIP D) and (-) Negative battery cable connection.

If the LED Test Lamp blinks continuously when the engine is cranked, replace the DIS module.  Otherwise go to N23.

Key off

Reconnect DIS Module Connector Pins 1-6

Connect LED Test Lamp between (+) Pin 4 on the Crank Sensor Connector (VBAT PS) and (-) Pin 7 of the DIS Connector (IGND D)

Key on

If the LED Test lamp is on, go to N24, otherwise check the connectors and service or replace the harness. 

Key off

Measure resistance between Pin 3 of the Crank Sensor Plug (IGND PS) and Pin 7 of the DIS Connector (IGND D).

If the resistance is less than 5 ohms, go to N25, otherwise check connectors and service or replace the harness.

Connect LED Test Lamp between (+) Pin 2 of the Crank Connector (PIP S) and (-) Pin 7 of the DIS Connector (IGND D)

If the LED Test Lamp blinks continuously when the engine is cranked check the connectors and service or replace the harness.  If not, then go to N26.

Key off

Disconnect Crankshaft sensor

Disconnect DIS Module Connector Pins 1-6

Connect LED Test Lamp between (-) Pin 2 of the CrankShaft Sensor (PIP S) and Positive Battery Cable connection.

Key on

If the LED Test lamp is on, PIP S is shorted to ground between the sensor and the DIS module.  Check connectors and service or replace the harness.  Otherwise go to N27

Key off

Connect LED Test Lamp between (+) Pin 2 of the CrankShaft Sensor (PIP S) and the Negative battery cable connector.

Key on

If the LED Test Lamp is on, PIP S is shorted to the VBAT between sensor and DOS Module.  Check connectors, service or replace harness.  Otherwise go to N28.

Key off

Disconnect EEC-IV processor from vehicle harness.

Connect LED Test Lamp between (-) (PIP EEC) and Positive battery cable connector.

Key on

If the LED Test Lamp is on, check the connectors, service or replace the harness.  Otherwise go to N29.

Connect LED Test Lamp between (-) Pin 1 on the Crankshaft Sensor (PIP EEC) and Negative battery cable connection.

Key On.

If the LED Test lamp is on, check the connectors, service or replace the harness.  Otherwise go to N30.

Check to make sure the crankshaft vane moves through sensor air gap when the engine is cranked.  If it does, replace the Crankshaft Sensor.  If not, then you have bigger problems.  Search SCCOA for "Balancer" and "broken".