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Ignition System - 5.8l Dura-Spark Ii Ford LTD Crown Victoria I

Ignition System 5 illustrations ~3007 words

DESCRIPTION

The Dura-Spark II (UIC) ignition system consists of a breakerless distributor, an Electronic Control Module (ECM), a Universal Ignition Control (UIC) circuit, ignition coil, battery, ignition switch, and necessary wiring harnesses. (Scheme 1) The UIC circuit is identified by a 3-wire harness, connecting the ECM to distributor. The UIC circuit adjusts base timing to compensate for altitude and engine load.

DISTRIBUTOR

The permanent magnet in the pick-up coil causes a magnetic field to form around the pick-up coil. As the teeth of reluctor pass the pick-up coil, the magnetic field builds and collapses, causing a signal to be sent to the ECM. The control module switches the ignition coil primary circuit on and off, causing a high voltage surge in the coil secondary windings.

The Dura-Spark II (UIC) ignition system has an adapter between the distributor housing and cap. (Scheme 1) The distributor cap has male spark plug wire terminals that are larger than those on conventional distributors. The Dura-Spark II (UIC) distributor has centrifugal and vacuum advance mechanisms.

On single diaphragm vacuum units, increased vacuum causes pick-up coil to pivot on lower plate assembly, advancing spark timing. On dual diaphragm units, outer (primary) diaphragm operates from carburetor vacuum to provide timing advance during normal, off-idle, driving conditions. The inner (secondary) diaphragm operates from intake manifold vacuum and retards ignition timing during idle or deceleration.

Scheme 1

Scheme 1: DISTRIBUTOR
Scheme 1: DISTRIBUTOR

ELECTRONIC CONTROL MODULE

The Dura-Spark II (UIC) control module utilizes a 2-wire and a 4-wire connector. The UIC distributor uses a 3-wire connector. (Scheme 1) The White wire functions as an ignition feed wire when ignition switch is in the "START" position. The Red wire has a built-in 1.1 ohm resistance and functions as the ignition feed wire when ignition switch is in the "RUN" position.

Current to ignition coil primary circuit is switched on and off through the Green wire. The Orange and Purple wires transmit signals from the reluctor and pick-up coil to the ECM. The Black wire grounds the ECM through the distributor housing.

IGNITION COIL

The ignition coil is energized whenever ignition switch is in the "ON" or "START" positions. The coil has a positive "BATT" terminal, a negative tachometer "TACH" terminal, and a secondary high voltage terminal. A special connector attaches the control module Green wire to the "TACH" terminal, and the ignition feed wire from ignition switch to the "BATT" terminal.

SYSTEM PROTECTION

Although the Dura-Spark II (UIC) ignition system is protected against transient electrical currents, damage to the ignition system may occur if proper testing procedures are not followed.

SYSTEM PRECAUTIONS

The ECM and ignition coil are energized whenever the ignition switch is in the "ON" or "START" positions. Therefore, the system will generate a spark whenever the ignition switch is turned to the "OFF" position. This feature may be used as a diagnostic tool to check for continuity of circuit, coil, and ignition switch.

Spark may occur if distributor cap is removed with switch in the "ON" position. Unless you plan to start engine or perform a test requiring switch to be on, maintain switch in "OFF" position to prevent accidental engine rotation during service or test procedures.

Silicone dielectric grease must be applied to all insulating areas of distributor, coil, and spark plug boots. To help prevent radio frequency interference, coat distributor rotor tip with dielectric grease to a thickness of 1/32".

When removing distributor cap and adapter, DO NOT remove cap and adapter as an assembly. Always remove distributor cap, rotor, and then adapter. A 3/4" clearance must be maintained at distributor cap mounting edge, spark plug wire terminals, and coil tower to prevent high voltage arc to ground.

ADJUSTMENTS

Initial ignition timing and spark plug gap are the only adjustments which can be made to this ignition system.

TESTING

Note. All wire colors shown refer to colors of ECM wires. When making tests, wires must be traced back to control module for proper color identification.

SPARK PLUG WIRE RESISTANCE

  1. Remove distributor cap. Disconnect spark plug wire at spark plug. Connect ohmmeter between spark plug end of wire and corresponding terminal inside cap. DO NOT puncture spark plug wire.
  2. If reading is less than 7000 ohms per foot, spark plug wire is okay. If reading is more than 7000 ohms per foot, replace spark plug wire(s). After test, install distributor cap and connect spark plug wire(s)

START CIRCUIT

  1. Connect Spark Tester (D81P-6666-A) between ignition coil wire and a good engine ground. (Scheme 2) Crank engine using vehicle's ignition switch. If no sparks occur at tester, go to next step. If spark occurs at tester, go to «RUN CIRCUIT»(/ford/ltd-crown-victoria/i-1983-1991/remont/ignition-system/#ignition-system-58l-dura-spark-ii__run-circuit) test.
  2. Remove coil wire from distributor cap and ignition coil. Connect ohmmeter leads to ends of wire and measure resistance. If resistance is more than 7000 ohms per foot, replace coil wire. Inspect ignition coil for damage or carbon tracking. Crank engine to verify distributor rotation. If these items are okay, proceed to the «VOLTAGE SUPPLY CIRCUIT»(/ford/ltd-crown-victoria/i-1983-1991/remont/ignition-system/#ignition-system-58l-dura-spark-ii__voltage-supply-circuit) test.

Scheme 2

Scheme 2
Scheme 2

RUN CIRCUIT

  1. Remove ignition coil wire from distributor cap and connect spark tester to wire. Turn ignition switch from "OFF" to "RUN" position several times. Sparks should occur each time switch is turned from "RUN" to "OFF" position. If no sparks occur, proceed to the «CONTROL MODULE VOLTAGE»(/ford/ltd-crown-victoria/i-1983-1991/remont/ignition-system/#ignition-system-58l-dura-spark-ii__control-module-voltage) test.
  2. If sparks occurred, check distributor cap, adapter, and rotor for cracks, carbon tracking, or lack of silicone dielectric compound. Ensure reluctor-to-distributor shaft retaining pin is in place. Ensure that Orange and Purple wires are not crossed between distributor and control module. If ignition module (Ford Motor Co. Part No. -12A244-1-) is being used, go to «SPARK TIMING»(/ford/ltd-crown-victoria/i-1983-1991/remont/ignition-system/#ignition-system-58l-dura-spark-ii) test and check ignition timing retard function.

CONTROL MODULE VOLTAGE

  1. With ignition switch in "OFF" position, insert a small straight-pin in Red module wire. (Scheme 3) DO NOT allow straight-pin to contact an electrical ground. Attach negative voltmeter lead to distributor base and positive lead to battery positive terminal and measure voltage. Turn ignition switch to "ON" position and measure voltage at straight-pin.
  2. If voltage is at least 90% of battery voltage, go to RESISTANCE WIRE test. If reading is less than 90% of battery voltage, check wiring harness between control module and ignition switch. Also check for worn or damaged ignition switch. After test, turn ignition off and remove straight-pin.

RESISTANCE WIRE

  1. Disconnect 2-wire (Red and White wire) connector at control module. Disconnect and inspect ignition coil connector. Connect ohmmeter between "BATT" terminal of coil connector and Red wire on harness side of 2-wire connector.
  2. If resistance is 0.8-1.6 ohms, problem is either intermittent or not in ignition system. If resistance is less than 0.8 ohms or more than 1.6 ohms, replace resistance wire. After test, reconnect all connectors.

Scheme 3

Scheme 3
Scheme 3

VOLTAGE SUPPLY CIRCUIT

  1. Remove spark tester and reconnect coil wire to cap. If starter relay has an "I" terminal, disconnect cable going to starter motor. If starter relay does not have an "I" terminal, disconnect wire to "S" terminal of starter relay. Insert small straight-pins in Red and White control module wires. DO NOT allow straight-pins to contact an electrical ground.
  2. Measure battery voltage. Connect negative voltmeter lead to distributor base, and note voltmeter reading in each of the following circuits. See «VOLTAGE SUPPLY CIRCUIT TEST»(/ford/ltd-crown-victoria/i-1983-1991/remont/ignition-system/#ignition-system-58l-dura-spark-ii) table. Wiggle wiring harness when measuring voltage. VOLTAGE SUPPLY CIRCUIT TEST Wire/Terminal Circuit Ignition Switch Test Position Red Run Run White Start Start "BATT" Resistance Wire Start
  3. If voltage readings are at least 90 percent of battery voltage, go to «IGNITION COIL VOLTAGE SUPPLY»(/ford/ltd-crown-victoria/i-1983-1991/remont/ignition-system/#ignition-system-58l-dura-spark-ii__ignition-coil-voltage-supply) test. If readings are less than 90 percent of battery voltage, check for faulty wiring harness or connectors. Check radio interference capacitor on ignition coil. Also check for worn or damaged ignition switch.
  4. After testing circuits, turn ignition off. Remove straight-pins. Connect starter cable and/or any wires disconnected from starter relay.

IGNITION COIL VOLTAGE SUPPLY

  1. Connect negative lead of voltmeter to distributor base and positive lead to "BATT" terminal of ignition coil. Turn ignition switch to "RUN" position and read voltmeter. Turn ignition switch to "OFF" position.
  2. If reading is 6-8 volts, go to PICK-UP COIL ASSEMBLY & DISTRIBUTOR WIRING HARNESS test. If reading is less than 6 volts or more than 8 volts, go to «IGNITION COIL PRIMARY RESISTANCE»(/ford/ltd-crown-victoria/i-1983-1991/remont/ignition-system/#ignition-system-58l-dura-spark-ii__ignition-coil-primary-resistance) test.

PICK-UP COIL ASSEMBLY & DISTRIBUTOR WIRING HARNESS

  1. Disconnect control module 4-wire connector and inspect for dirt, corrosion, or damage. Connect ohmmeter between connector terminals that mate with Orange and Purple control module wires. Wiggle wiring harness when measuring resistance.
  2. If reading is between 400-1300 ohms, proceed to the «CONTROL MODULE-TO-DISTRIBUTOR WIRING HARNESS»(/ford/ltd-crown-victoria/i-1983-1991/remont/ignition-system/#ignition-system-58l-dura-spark-ii__control-module-to-distributor-wiring-harness) check. If reading is less than 400 ohms or more than 1300 ohms, go to «PICK-UP COIL RESISTANCE»(/ford/ltd-crown-victoria/i-1983-1991/remont/ignition-system/#ignition-system-58l-dura-spark-ii__pick-up-coil-resistance) check.
  1. Remove distributor cap, rotor, and adapter. Disconnect distributor wiring harness plug. Using 2 screwdrivers, carefully pry armature from sleeve and plate assembly. Remove roll pin. DO NOT pinch stator wires when removing armature.
  2. Remove large wire retaining clip from base plate annular groove. Remove ground screw base and pull up to remove rubber grommet from base. Remove "E" clip holding diaphragm rod advance link to stator.
  3. Lift diaphragm rod off post on stator assembly, and move it out against housing. Remove stator assembly. To assemble, reverse disassembly procedure. Install a new roll pin when installing armature.

Scheme 4

Scheme 4
Scheme 4

Scheme 5

Scheme 5: WIRING DIAGRAM
Scheme 5: WIRING DIAGRAM

CONTROL MODULE-TO-DISTRIBUTOR WIRING HARNESS

  1. Disconnect 4-wire control module connector. Connect one lead of ohmmeter to distributor base. Alternately, connect other ohmmeter lead to wiring harness connector terminals that mate with Orange and Purple wires of control module connector.
  2. If reading is greater than 70,000 ohms, proceed to the «IGNITION COIL SECONDARY RESISTANCE»(/ford/ltd-crown-victoria/i-1983-1991/remont/ignition-system/#ignition-system-58l-dura-spark-ii__ignition-coil-secondary-resistance) test. If reading is less than 70,000 ohms, check distributor connector and wiring harness between control module connector and distributor. After test, reconnect 4-wire connector.

IGNITION COIL SECONDARY RESISTANCE

  1. Disconnect and inspect ignition coil connector and coil wire. Connect ohmmeter between ignition coil "BATT" terminal and high voltage terminal. (Scheme 5)
  2. If reading is 7700-10,500 ohms, coil is okay. Go to MODULE-TO-COIL WIRE TEST. If reading is less than 7700 or greater than 10,500 ohms, replace ignition coil. After test, connect coil wire.

MODULE-TO-COIL WIRE

  1. Disconnect and inspect ignition module 4-wire connector. Disconnect ignition coil connector. Connect ohmmeter between distributor base and "TACH" terminal of ignition coil connector.
  2. If reading exceeds 100 ohms, replace control module. If reading is 100 ohms or less, inspect wiring harness between control module and ignition coil. After test, connect ignition module and coil connectors.

PICK-UP COIL RESISTANCE

  1. Disconnect distributor connector from wiring harness and inspect for dirt, corrosion, or damage. Measure resistance across Orange and Purple wires at distributor connector.
  2. If reading is between 400-1000 ohms, pick-up coil is okay. Inspect wiring harness between distributor and ignition module. If reading is less than 400 ohms or more than 1000 ohms, replace pick-up coil assembly. After test, connect ignition module and distributor connectors.

IGNITION COIL PRIMARY RESISTANCE

Disconnect ignition coil connector. Connect ohmmeter leads between "BATT" and "TACH" terminals of ignition coil. If reading is 0.8-1.6 ohms, ignition coil is okay. Go to PRIMARY CIRCUIT CONTINUITY test. If reading is less than 0.8 or greater than 1.6 ohms, replace coil. After test, connect ignition coil connector.

PRIMARY CIRCUIT CONTINUITY

  1. Insert a small straight-pin in control module Green wire. DO NOT allow straight-pin to contact an electrical ground. Connect voltmeter between distributor base and pin in Green wire.
  2. With ignition switch in "RUN" position, measure voltage. If reading exceeds 1.5 volts, go to «GROUND CIRCUIT CONTINUITY»(/ford/ltd-crown-victoria/i-1983-1991/remont/ignition-system/#ignition-system-58l-dura-spark-ii__ground-circuit-continuity) test. If reading is 1.5 volts or less, check wire between control module and ignition coil. After test, remove straight-pin.

GROUND CIRCUIT CONTINUITY

  1. Insert a small straight-pin in control module Black wire. DO NOT allow straight-pin to contact an electrical ground. Connect negative voltmeter lead to distributor base and positive lead to straight-pin in Black wire. Turn ignition switch to "RUN" position and measure voltage.
  2. If reading exceeds 0.5 volts, proceed to the «DISTRIBUTOR GROUND CIRCUIT CONTINUITY»(/ford/ltd-crown-victoria/i-1983-1991/remont/ignition-system/#ignition-system-58l-dura-spark-ii__distributor-ground-circuit-continuity) test. If reading is 0.5 volts or less, replace ignition control module. After test, remove straight-pin.

DISTRIBUTOR GROUND CIRCUIT CONTINUITY

  1. Disconnect distributor connector from wiring harness and inspect for dirt, corrosion, or damage. Connect ohmmeter between distributor base and Black wire terminal in distributor connector. Wiggle distributor grommet while measuring resistance.
  2. If reading is less than one ohm, circuit is okay. Check wiring harness and connectors between distributor and ignition module. If reading exceeds one ohm, check ground screw in distributor housing. After test, reconnect distributor.

Preliminary Information

Obtain an inductive timing light, a tachometer, and a 0-30 in. Hg vacuum gauge before performing test. Visually inspect engine compartment to ensure all vacuum hoses and spark plug wires are properly routed and securely attached. Use vehicle's emission label as a guide.

Examine all wiring harnesses and connectors for insulation damage, burnt or overheated wires, and loose or broken terminals. Ensure that battery is fully charged and that all accessories are off.

Initial (Base) Timing Test

  1. Disconnect and plug distributor vacuum hose(s). Connect timing light and tachometer to engine. If ignition module (Part No. -12A244-) is being used, disconnect 2-wire (Yellow and Black wire) connector. Install jumper wire between module connector pins and go to next step. If above named ignition module is not used, go directly to next step.
  2. Start and run engine until normal operating temperature is reached. Ensure engine speed is at or below 600 RPM. Adjust if necessary. Check initial (base) ignition timing. If timing is 12-16 degrees, go to next test. If not, adjust as necessary. After adjustment, go to next test.

Ignition Module (Part No. -12A244-) & Ignition Barometric Pressure Switch (Part No. -12A243-) Test.

  1. If ignition module (Part No. -12A244-) is being used, remove jumper wire from 2-wire connector, reconnect harness, and go to next step. If above named ignition module is not used, go directly to the CENTRIFUGAL ADVANCE MECHANISM test below.
  2. Check initial (base) ignition timing once again. If timing is 12-16 degrees, disconnect 2-wire (Yellow and Black wire) connector at ignition module and go to next step. If initial (base) timing changed, go to «5.8L MCU SYSTEM»(/ford/ltd-crown-victoria/i-1983-1991/remont/testing-diagnostics/#58l-mcu-system) article in COMPUTERIZED ENGINE CONTROLS section. NOTE: Engine may quit when connector is disconnected due to excessive spark retard. If this happens, spark retard function is okay. Reconnect 2-wire connector and go directly to CENTRIFUGAL ADVANCE MECHANISM test below.
  3. Check initial (base) ignition timing one more time. If initial (base) ignition timing is now retarded, ignition system retard function is okay. Reconnect vacuum hose. If initial (base) timing did NOT retard, go to next step.
  4. Install a known good ignition module. Connect 2-wire (Red and White Wire) and 4-wire connectors. Install jumper wire between pins in 2-wire (Yellow and Black wire) connector. Check initial (base) timing. If timing is 12-16 degrees, go back to step 2). If initial (base) timing changed, repeat this step. NOTE: If substitute ignition module appears to correct problem, install original module and repeat step 4) to verify repair. Centrifugal Advance Mechanism Test
  1. Disconnect vacuum advance hose and increase engine speed to 2500 RPM. Check ignition timing with vacuum advance hose disconnected and then allow engine to return to idle. If ignition timing advanced, go to next step. If timing did not advance, replace distributor. After service, repeat this step.
  2. Check initial (base) timing at 600 RPM. If ignition timing is 12-16 degrees, distributor centrifugal advance mechanism is okay. Go to next test. If initial (base) timing is incorrect, replace distributor.

Vacuum Advance Mechanism Test

  1. Connect distributor advance hose to distributor. Increase engine speed to 2500 RPM and hold for 60 seconds. Check ignition timing with vacuum advance hose connected and then allow engine to return to idle. If ignition timing advanced, vacuum advance mechanism is okay. Go to VACUUM RETARD MECHANISM test below. If timing did not advance, go to next step.
  2. Using vacuum hose "T", connect vacuum gauge in vacuum advance hose. Increase engine speed to 2500 RPM and hold for 60 seconds. Check vacuum gauge for presence of vacuum and then allow engine to return to idle. If vacuum reading is at least 15 in. Hg, inspect vacuum diaphragm for leaks and/or pick-up assembly for binding. Repair or replace as necessary. After repairs, repeat step 1). If vacuum reading is low, go to next step.
  3. Check engine vacuum control valves and related vacuum hoses for proper operation, routing, or damage. Use vehicle's emission label as a guide. If valves and hose are okay, go to next step. If not, repair or replace as necessary.
  4. Disconnect and plug distributor vacuum advance hose. Attach a vacuum hose directly between distributor vacuum advance diaphragm and intake manifold (alternate vacuum source). Increase engine speed to 2500 RPM. Check ignition timing and then allow engine to return to idle. If timing advanced, check vacuum source. Remove vacuum gauge and repeat step 1).
  5. If timing did not advance, inspect vacuum diaphragm for leaks and/or pick-up assembly for binding. Repair or replace as necessary. Disconnect alternate vacuum source. Connect normal vacuum source and repeat step 1).

Vacuum Retard Mechanism Test

  1. If vehicle is not equipped with dual (retard) diaphragm, ignition timing system is okay. If dual (retard) diaphragm is used, go to next step.
  2. Disconnect and plug vacuum hose to vacuum advance diaphragm. Connect vacuum hose to distributor retard diaphragm. Check ignition timing at idle speed. If ignition timing is retarded (below 12 degrees), ignition timing system is okay. Connect vacuum hose to advance diaphragm. If timing did NOT retard, go to next step.
  3. Using vacuum hose "T", connect vacuum gauge in vacuum retard hose going to diaphragm. Check for presence of vacuum at idle. If reading is at least 15 in. Hg, replace distributor diaphragm assembly and repeat step 2). If vacuum reading is low, check vacuum source and repeat step 2).

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