Engine Controls - System/component Tests: Diagnosis Ford Aerostar I

Fuel Pressure Test

1. Ensure fuel tank has adequate fuel. Turn ignition off. Install fuel pressure gauge. Install a test lead to Fuel Pump (FP) lead of VIP test connector. (Scheme 106) Turn ignition on, engine off. Ground test lead to run fuel pump. Check fuel pressure. See «FUEL PRESSURE SPECIFICATIONS»(ref-123317). If fuel pressure is within specification, go to step 5). If fuel pressure is not within specification, go to next step.
2. If pressure is low, but greater than 3 PSI (21 kPa), go to next step. If pressure is not more than 3 PSI (21 kPa) go to step 4).
3. Check fuel system for: Plugged fuel filter (replace filter and check again for proper pressure). Kinked/restricted fuel lines (visual inspection). Low voltage to fuel pump (should be within 0.5 volt of battery voltage at connector). Disconnect return fuel line and note if fuel is being returned during this low pressure condition. If fuel is being returned, replace or adjust pressure regulator. If a problem was found, repair as necessary. After repair, go to step 1) and retest system. If a problem was not found, replace fuel pump and go to step 1) and retest system.
4. Check the following electrical circuit problems: Ensure inertia switch is not open (reset switch as required). Wiring at fuel pump/tank connector loose or open. Fuel pump ground connection at chassis loose or defective. Improper fuel pump relay operation (should operate when fuel pump test lead is grounded with the ignition key on). EEC relay not operating if fuel pump relay doesn't operate. If a problem was found, repair as necessary. After repair, go to step 1) and retest system. If a problem was not found, replace fuel pump and go to step 1) and retest system.
5. Remove ground from test lead and note pressure on gauge. Pressure should remain within 2 PSI (14 kPa) for 3 minutes after lead is ungrounded. If pressure holds as specified, go to step 7). If pressure does not hold as specified, go to next step.
6. Check fuel lines and connectors for leakage. Disconnect fuel return line and plug engine side. Momentarily activate fuel pump by grounding test lead. Raise pressure to approximate operating pressure and repeat step 5). If pressure holds, replace pressure regulator and repeat step 5). If a problem was found and repaired, go to step 1) and retest system. If a problem was not found, replace fuel pump and go to step 1) and retest system. If system still fails step 5), there may be a leaking fuel injector or rail. Repair as necessary and go to step 5).
7. Disconnect and plug vacuum line connected to the pressure regulator. Start engine and run at idle. Check fuel pressure. See «FUEL PRESSURE SPECIFICATIONS»(ref-123316). If fuel pressure is within specification, go to step 9). If fuel pressure is not within specification, go to next step.
8. Check the following for cause of low pressure: Fuel filter restriction. Improper fuel regulator adjustment. Fuel line restricted. Improper voltage to fuel pump (battery voltage at pump connections). If a problem was found, repair as necessary. After repair, go to step 1) and retest system. If a problem was not found, replace fuel pump and go to step 1) and retest system.
9. With engine running at idle and vacuum line disconnected, note fuel rail pressure. Rapidly accelerate engine and watch fuel pressure. If pressure remains within 5 PSI of starting pressure, system is okay. If pressure does not remain within 5 PSI of starting pressure, go to step 8).

Scheme 106

Duel Function Reservoir Testing (Dual Tanks)

1. Remove all lines from reservoir, note position and routing of lines and avoid fuel spillage. Apply 3-5 PSI (20.7-34.5 kPa) of air pressure to return port (small diameter tube) on engine side of reservoir (only one set of 2 ports). If air is out of only one port on the other side of reservoir, go to step 3). If air is not out of only one port on the other side of reservoir, go to next step.
2. Block pressure port (large diameter tube) on engine side of the reservoir. Apply 3-5 PSI (20.7-34.5 kPa) of air to either of the pressure ports on the fuel tank side of the reservoir. Remove air and apply to return tube on engine side of reservoir as in step 1). If the pressure is out of only one return port on the other side of the reservoir, go to next step. If the air pressure is not out of only one return port on the other side of the reservoir, replace reservoir.
3. Block engine pressure port of reservoir. Apply 3-5 PSI (20.7-34.5 kPa) of air to one pressure port and the corresponding return port on the fuel tank side of the reservoir. If air pressure is out of return port on engine side of reservoir, go to next step. If air pressure is not out of the return port on the engine side of reservoir, change to opposite return port and repeat this step. If reservoir fails, replace reservoir.
4. Remove air from pressure port tested previously and apply air to other set of ports on reservoir. If the air pressure is out of the return port on the engine side, go to next step. If the air pressure is not out of the return port on the engine side, check connection to return port. If connection is okay, replace reservoir.
5. Remove any blockage installed in the reservoir. Apply pressure to the engine side pressure port and note which port is open on the fuel tank side of the reservoir. Attach a pressure gauge (0-110 in. H2O) to the closed pressure port. Block the open port on the tank side of the reservoir. If pressure is present on the gauge, replace reservoir. If pressure is not present, go to next step.
6. Remove the pressure and gauge from selected port in step 5). Attach gauge to closed return port. Apply pressure to return port on engine side and block open return port. If there is pressure on the gauge, replace the reservoir. If there is not pressure on the gauge, go reservoir is okay.

Scheme 107

High Pressure Fuel Pump Testing

1. Check fuel tank(s) for adequate fuel supply. Check for fuel leaks at fittings and lines. Install jumper lead to fuel pump test terminal of VIP test connector. (Scheme 106) Use a test lead long enough to reach under vehicle. Install fuel pressure gauge. Turn ignition switch to the "RUN" position. Ground jumper lead and check fuel pressure. See «FUEL PRESSURE SPECIFICATIONS»(ref-123317). If fuel pressure is within specification, go to step 5). If fuel pressure is not within specification, go to step 2).
2. If fuel pressure is low but greater than 3 psi (indicates pump is working), go to step 3). If not, go to step 4).
3. Check fuel system for plugged fuel filter or restricted fuel lines. Check for low voltage at the fuel pump (voltage should be with.5 volt of battery voltage). Disconnect fuel return line. If fuel is returning, replace pressure regulator. If filters are clear, voltage correct and no fuel return, replace fuel pump.
4. Ensure that battery voltage and ground are present at fuel pump connector. If circuits and voltages are correct, replace fuel pump.
5. Disconnect grounded test lead and note fuel pressure. Fuel pressure should remain within 3 psi for 3 minutes after disconnecting test lead. If fuel pressure holds, go to step 7). If not, go to step 6).
6. Inspect for fuel leaks. If no leaks are found, disconnect and plug fuel return line. Ground test lead and raise pressure to normal level. If fuel pressure now holds, replace pressure regulator. If not, replace fuel pump.
7. Disconnect vacuum to fuel pressure regulator and start engine. Fuel pressure should be within specification. See «FUEL PRESSURE SPECIFICATIONS»(ref-123317). If fuel pressure is correct, go to step 9). If fuel pressure is not, go to step 8).
8. If fuel pressure is low, check fuel filter, fuel pressure regulator adjustment, fuel line restrictions or voltage to fuel pump. If all systems are normal, replace fuel pump.
9. With engine idling and fuel pressure regulator vacuum hose disconnected, measure fuel pressure. Accelerate rapidly and note fuel pressure. If fuel pressure drops more than 5 psi, repeat step 8). If fuel pressure does not drop, fuel system is operating correctly.

Low Pressure Fuel Pump Testing

1. Check fuel tank(s) for adequate fuel supply. Check for fuel leaks at fittings and lines. Install jumper lead to fuel pump test terminal of VIP test connector. (Scheme 108) Use a test lead long enough to reach under vehicle. Raise vehicle and ground test lead. Use a stethoscope and listen for pump operation. If low pressure pump is running, go to step 2). If not, go to step 3).
2. Disconnect test lead from ground. Remove reservoir inlet hose at reservoir. Place fuel hose in one quart calibrated container and ground test lead for 5 seconds. Fuel level should be at least 6 ounces. If fuel pump volume is correct, fuel pump is okay. If not, restrict fuel line momentarily to prime pump. If no flow develops, check for blocked fuel lines. If no blockage is found, replace pump.
3. If pump does not run, inspect all electrical connections. Check inertia switch and fuel pump relay for operation. If high pressure pump runs, but low pressure pump does not and voltage is present, replace low pressure fuel pump.

In-Tank Reservoir (ITR) Fuel Pump Testing

1. Ensure fuel tank has adequate fuel. Turn ignition off. Install fuel pressure gauge. Install a test lead to Fuel Pump (FP) lead of VIP test connector. (Scheme 108) Turn ignition on, engine off. Ground test lead to run fuel pump. Check fuel pressure. See «FUEL PRESSURE SPECIFICATIONS»(ref-123317). If fuel pressure is within specification, go to step 5). If fuel pressure is not within specification, go to next step.
2. If pressure is low, but greater than 3 PSI (21 kPa), go to next step. If pressure is not more than 3 PSI (21 kPa) go to step 4).
3. Check fuel system for: Plugged fuel filter (replace filter and check again for proper pressure). Kinked/restricted fuel lines (visual inspection). Low voltage to fuel pump (should be within 0.5 volt of battery voltage at connector). Disconnect return fuel line and note if fuel is being returned during this low pressure condition. If fuel is being returned, replace or adjust pressure regulator. If a problem was found, repair as necessary. After repair, go to step 1) and retest system. If a problem was not found, replace fuel pump and go to step 1) and retest system.
4. Check the following electrical circuit problems: Ensure inertia switch is not open (reset switch as required). Wiring at fuel pump/tank connector loose or open. Fuel pump ground connection at chassis loose or defective. Improper fuel pump relay operation (should operate when fuel pump test lead is grounded with the ignition key on). EEC relay not operating if fuel pump relay doesn't operate. If a problem was found, repair as necessary. After repair, go to step 1) and retest system. If a problem was not found, replace fuel pump and go to step 1) and retest system.
5. Remove ground from test lead and note pressure on gauge. Pressure should remain within 2 PSI (14 kPa) for 3 minutes after lead is ungrounded. If pressure holds as specified, go to step 7). If pressure does not hold as specified, go to next step.
6. Check fuel lines and connectors for leakage. Disconnect fuel return line and plug engine side. Momentarily activate fuel pump by grounding test lead. Raise pressure to approximate operating pressure and repeat step 5). If pressure holds, replace pressure regulator and repeat step 5). If pressure decays rapidly, go to next step. If system still fails step 5), there may be a leaking fuel injector or rail. Repair as necessary and go to step 5).
7. If pressure decays rapidly enough that needle movement can be observed, replace ITR unit if equipped with a single tank. If equipped with dual tanks, go to next step. If pressure holds, go to step 10).
8. Remove fuel supply line from sender port of midship tank. Change pressure gauge from 5/16" to 3/8" adaptor to fit fuel line quick connector. Connect gauge to end of supply line removed from midship sender. Move the tank selector switch to REAR tank position. Turn ignition on and hold until fuel pump shuts itself off (approximately one second). Turn ignition off. Observe pressure gauge. If pressure holds steady, go to next step. If pressure does not hold steady, replace rear ITR unit and go to next step.
9. Remove fuel pressure gauge from supply line. Install a 3/8" right-angle quick-connector to pressure gauge. Connect gauge to midship tank ITR supply port. Move the tank selector switch to the FRONT tank position. Turn ignition to on position and hold until fuel pump shuts itself off (approximately one second). Turn ignition off. Observe pressure gauge. If pressure holds steady, midship ITR unit is okay. Remove fuel pressure gauge and reconnect all fuel lines. Go to step 1) to retest system. If pressure does not hold steady, replace midship ITR unit. Go to step 1 to retest system.
10. Disconnect and plug vacuum line connected to the pressure regulator. Start engine and run at idle. Check fuel pressure. See «FUEL PRESSURE SPECIFICATIONS»(ref-123317). If fuel pressure is within specification, go to step 12). If fuel pressure is not within specification, go to next step.
11. Check the following for cause of low pressure: Fuel filter restriction. Improper fuel regulator adjustment. Fuel line restricted. Improper voltage to fuel pump (battery voltage at pump connections). If a problem was found, repair as necessary. After repair, go to step 1) and retest system. If a problem was not found, replace fuel pump and go to step 1) and retest system.
12. With engine running at idle and vacuum line disconnected, note fuel rail pressure. Rapidly accelerate engine and watch fuel pressure. If pressure remains within 5 PSI of starting pressure, system is okay. If pressure does not remain within 5 PSI of starting pressure, go to step 11).

Scheme 108

1. Ensure key is off. Connect fuel pressure gauge to Schrader valve on fuel rail. Ensure manifold vacuum supply tube is connected to fuel pressure regulator. Start and run engine for 10 seconds. Stop engine and wait 10 seconds. Start and operate engine for 10 seconds. Stop engine and remove pressure regulator vacuum hose. (Scheme 108) Check vacuum port for fuel.
2. If fuel is present, replace fuel pressure regulator and repeat test. If fuel is not present, start and run engine for 30 seconds. Stop engine and check fuel pressure gauge. If fuel pressure does not drop, go to step 4). If fuel pressure drops more than 5 psi (34.5 kPa) in 60 seconds, disconnect and plug fuel return line at engine. Cycle ignition key on and off until normal fuel pressure is obtained.
3. Turn key off and check fuel pressure gauge. If gauge drops more than 5 psi (34.5 kPa) in 30 seconds, replace high pressure fuel pump (dual pump system) or fuel sender/pump assembly (single pump type). If gauge does not drop more than 5 psi (34.5 kPa) in 30 seconds, replace fuel pressure regulator.
4. Ensure key is off. Relieve fuel pressure. Remove fuel pressure regulator. Check "O" ring, gasket and mounting surfaces for cracks, cuts or other damage. Connect vacuum pump to fuel return tube and apply 20 in. Hg. If maximum vacuum loss exceeds 10 in. Hg in 10 seconds, replace regulator. If maximum vacuum loss does not exceed 10 in. Hg in 10 seconds, recheck entire fuel delivery system for cause of fuel pressure loss.

TEST EQUIPMENT

Following test equipment should be used in TFI-IV ignition system tests.

1. Spark Tester (D81P-6666-A)
2. Volt-Ohmmeter
3. 12-Volt Test Light
4. Small Straight Pin
5. Remote Starter Switch
6. E-Core Ignition Coil (E73F-12029-AB)
7. Ignition Coil Secondary Wire

DIAGNOSTIC AIDS

Following information should be noted during testing

1. A spark plug with a broken side electrode is NOT sufficient to check for spark and may lead to incorrect results.
2. When instructed to inspect a wiring harness, both a visual inspection and a continuity test should be performed.
3. When making measurements on a wiring harness or connector, perform a WIGGLE test while measuring.
4. References to SPOUT in-line connector apply to both in-line and shorting-bar type connectors.
5. Test procedures are intended to identify faulty components or wiring while fault is present. If complaint is an intermittent condition, refer to TESTS W/O CODES article in the ENGINE PERFORMANCE Section.

Scheme 109

1. Disconnect terminal "S" at starter relay to allow testing of ignition primary circuit without cranking motor. Ensure ignition is off. Push down on connector tab and disconnect harness connector from TFI module. Ensure TFI module connector is not corroded or swollen. Repair or replace connector as necessary. NOTE: If connector is damaged or has broken tabs due to misuse, replace connector. A loose or damaged connector may cause ignition signal faults during KOER operation.
2. Use a straight pin or terminal spade from an old TFI module to probe connector. Attach negative DVOM lead to distributor base. Avoid ground contact with straight pin or positive terminal lead during testing. Turn ignition on and measure voltage at following TFI module harness connector terminals: (Scheme 109) Key On Engine Cranking (KOEC) No. 3 (Power/Run Circuit) Key On Engine Off (KOEO) No. 4 (Start Circuit) No. 3 (Power/Run Circuit)
3. Turn ignition off and remove test pin. Reconnect wire to "S" terminal on relay. If approximately 90% of Battery Voltage (VBAT) is not present at these terminals, repair open circuits in wiring harness as necessary. Check ignition switch for faults. See appropriate wiring diagram. If voltage was as specified, reconnect module and go to next step.
4. Attach a 12-volt test light between ground and coil negative (-)/tach terminal No. 2 at TFI module. Turn ignition on, and crank engine. If test light flashes brightly during cranking, go to appropriate PIP SENSOR/STATOR TEST. If test light stays on during cranking, check for open in coil negative circuit between coil and TFI module connector. Repair circuit as necessary. If no open circuits are found, ignition module is shorted internally. Replace TFI module and retest.
5. If test light is always dim or off during cranking, check voltage to coil positive (+) terminal. If voltage is not present with key on or during cranking, repair open in primary circuit between battery and coil positive (+). If light flashes intermittently, check ignition module resistance. If voltage is available at coil, go to COIL TEST and check ignition coil.

Scheme 110

1. Disconnect terminal "S" at starter relay to allow testing of ignition primary circuit without cranking motor. Ensure ignition is off. Push down on connector tab and disconnect harness connector from TFI module. Ensure TFI module connector is not corroded or swollen. Repair or replace connector as necessary. NOTE: If connector is damaged or has broken tabs due to misuse, replace connector. A loose or damaged connector may cause ignition signal faults during KOER operation.
2. Use a straight pin or terminal spade from an old TFI module to probe connector. Avoid ground contact, between straight pin and ground, during testing. Using a DVOM, turn ignition on and measure voltage at following vehicle harness connector terminals of cowl mounted TFI module: (Scheme 109) Key On Engine Cranking (KOEC) No. 3 (Power/Run Circuit) No. 4 (Start Circuit) Key On Engine Off (KOEO) No. 3 (Power/Run Circuit) If approximate Battery Voltage (VBAT) is not present at these terminals, repair open circuits in wiring harness as necessary. See appropriate wiring diagram in WIRING DIAGRAMS article in the ENGINE PERFORMANCE Section.
3. If battery voltage is as specified, check module ground circuit. With TFI module disconnected and KOEO, measure voltage at terminal No. 6. If voltage is greater than.5 volt, ground circuit has high resistance or is open. Repair as necessary.
4. Ensure ignition is off. Disconnect distributor connector. Turn ignition on. With DVOM set on DC voltage scale, connect positive (+) lead to terminal No. 8 (terminal No. 4 on 3.0L Aerostar and Ranger). Connect negative (-) lead to distributor or engine ground. (Scheme 110)
5. Cycle ignition switch between ON and START positions. Battery voltage should be present in both positions. If not, service or repair circuit as necessary. If okay, go to next step.
6. Use a DVOM to check ignition ground circuits continuity. Measure resistance between distributor base and terminals No. 2 and No. 6 at distributor connector (terminal No. 3 on 3.0L Aerostar and Ranger). If resistance at each terminal is less than 3 ohms, circuit is okay. If resistance is 3 ohms or more, repair ground circuit as necessary. (Scheme 111)

Scheme 111

TFI MODULE RESISTANCE TEST

1. Remove TFI module from distributor or disconnect cowl. Measure resistance of TFI module circuits. See «TFI MODULE RESISTANCE»(ref-22719-S13257674262001010300000). (Scheme 109)- (Scheme 111).
2. If resistance is as specified, suspect faulty PIP sensor/stator. If resistance is NOT as specified, replace TFI-IV module.

TFI MODULE RESISTANCE

PIP SENSOR/STATOR TEST (EXCEPT CLOSED BOWL DISTRIBUTOR)

1. Ensure TFI module mounting screws are tight on distributor. Turn ignition off. Remove coil wire at distributor cap and ground end of wire. Ensure wire does not break contact with ground during this test.
2. Disconnect SPOUT connector located near distributor. Connect positive (+) lead of DVOM to TFI module side of SPOUT connector and negative lead to distributor base.
3. Turn ignition switch to ON position and bump starter to rotate engine a small amount. Measure and record voltage (allow DVOM voltage reading to stabilize). Repeat procedure 10 times. Voltage should vary as hall sensor vanes and windows rotate through PIP sensor.
4. Voltage reading should vary between .5 volt and 11.5 volts (90% of battery voltage). If the higher voltage readings are only about 70% of battery voltage, go to TFI MODULE RESISTANCE TEST. If TFI module has excessive resistance, replace TFI module. If resistance is not excessive, replace PIP sensor.
5. If the lower voltage readings are greater than .5 volt and ignition module resistance is within specification, replace PIP sensor. If PIP sensor and module test okay, go to next step to check for PIP signal at ECA during cranking.
6. Turn ignition off and install Break Out Box (BOB) at ECA connector. Connect a DVOM between test terminals No. 56 (PIP) and No. 16 (IGN GND). Measure PIP signal voltage while cranking engine. Voltage should vary between 4 and 6 volts. If not, check for an open or grounded PIP circuit or an open IGN GND circuit at test terminal No. 16. Repair circuits as necessary. If circuits are okay, but PIP signal is erratic or not present, go to next step.
7. With ECA and TFI module disconnected, connect DVOM positive (+) lead to PIP circuit at harness connector and ensure circuit is not shorted to power during engine cranking. If circuit is okay, replace TFI module and retest system.

PIP SENSOR/STATOR TEST (CLOSED BOWL DISTRIBUTOR)

1. With ignition off, ensure distributor is connected to vehicle harness. Disconnect vehicle harness connector at TFI module. Connect DVOM positive (+) lead to terminal No. 6 at TFI vehicle harness connector. Connect negative (-) lead to ground.
2. Crank engine and measure DC voltage. Voltage should vary between 4 and 6 volts. If voltage varies, test SPOUT circuit. If voltage does not vary go to next step.
3. With ignition off, disconnect distributor connector. Using DVOM, measure resistance between terminals No. 1 and No. 5 at distributor connector. If resistance is 200 ohms or more, replace faulty PIP sensor.
4. Disconnect vehicle harness connector at TFI module. Measure resistance between terminal No. 6 (PIP) at TFI module vehicle harness connector and terminal No. 5 (PIP to TFI Module) at distributor vehicle harness connector. If resistance is 5 ohms or more, repair open in circuit and retest. Check circuit for short to ground. Test circuit for short to power with KOEO. Service or replace wiring as necessary.
5. Disconnect ECA connector and measure resistance between terminal No. 56 (PIP) at ECA 60-pin connector and terminal No. 5 (PIP to ECA Module) at distributor vehicle harness connector. If resistance is 5 ohms or more, repair open in circuit and retest. Check circuit for short to ground. Test circuit for short to power with KOEO. Service or replace wiring as necessary.
6. Measure resistance between distributor connector terminal No. 2 (PIP SIG GND) and ground. Measure resistance between IGN GND, distributor connector terminal No. 6 (terminal No. 3 on 3.0L Aerostar or Ranger) and ground. If resistance is less than one ohm in both cases, ground circuit is okay. If resistance is one ohm or more in both cases, check PIP sensor mounting screws in distributor base for corrosion and tightness.

COIL TEST

1. Attach negative (-) VOM lead to distributor base and measure battery voltage. Turn ignition switch to RUN position. Measure voltage at coil positive (+) terminal of ignition coil and turn ignition off. Voltage should be 10.5-12 volts. If voltage is as specified, go to next step. If voltage is not as specified, repair ignition switch or wiring circuit to coil. See appropriate wiring diagram in WIRING DIAGRAMS article in ENGINE PERFORMANCE Section.
2. Ensure ignition is off. Disconnect coil primary connector and inspect both contacts for corrosion or damage. Service or replace as necessary. Using a DVOM, measure primary circuit resistance. If resistance is not .3-1.0 ohm at 70°F, replace coil and retest system.
3. Remove secondary coil wire from coil tower and inspect contact for signs of arcing or corrosion. Using a DVOM, measure resistance between coil tower connector and coil negative (-) terminal. If resistance is not 8000-11,500 ohms, replace coil.

SPARK TIMING ADVANCE TEST

1. This procedure is applicable to all TFI-IV equipped vehicles. Spark advance is controlled by ECA. This procedure checks capability of ignition module to receive spark timing commands from ECA on the SPOUT circuit. A varying voltage signal is necessary on SPOUT circuit for ECA to transmit data. A KOER Code 18 or Code 213 may be set when SPOUT circuit is open or shorted. For additional information on TFI ignition systems, see THEORY/OPERATION article in the ENGINE PERFORMANCE Section.
2. Check SPOUT circuit voltage at TFI module. Ensure ignition switch is in OFF position. Disconnect SPOUT in-line connector near TFI module. If connector is SHORTING BAR type, remove SHORTING BAR.
3. Attach negative (-) voltmeter lead to distributor base and positive (+) lead to TFI module side of the SPOUT connector. Start engine and measure voltage at idle. Measure voltage at ECA side of SPOUT connector.
4. Voltage readings should be 4-8 volts. If voltage on TFI module side is okay, TFI module is okay. This voltage signal is necessary for TFI module to receive ECA SPOUT signal. If voltage signal from ECA to SPOUT connector is as specified, circuit from ECA to SPOUT connector is okay. If either voltage signal is not as specified, go to next test. If both voltage signals are as specified, check ignition timing advance.
5. Check SPOUT circuit continuity. Push TFI module connector tab to release connector. Separate wiring harness connector from ignition module. Inspect for dirt, corrosion and damage.
6. Using a small straight pin inserted into harness connector terminal No. 5, measure resistance between terminal and TFI module side of SPOUT connector. Resistance should be less than 5 ohms. If resistance is 5 ohms or more, repair wiring as necessary.
7. Measure resistance between ECA side of SPOUT connector and pin No. 36 at ECA connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair wiring between SPOUT connector and ECA.
8. Check Ignition Timing Advance. With SPOUT connector disconnected, run engine at idle and ensure timing is at base timing adjustment. See ADJUSTMENTS article in the ENGINE PERFORMANCE Section. Stop engine.
9. Connect SPOUT connector and start engine. Timing should advance from base timing specification. Increase engine RPM and ensure timing advances. If time does not advance, check TFI module. If module is okay, replace ECA.

Scheme 112

Scheme 113

Following test equipment is necessary to complete DIS ignition system tests.

1. DIS Diagnostic Cable (Rotunda 007-00044)
2. Spark Tester (Neon Bulb Type)
3. Digital Volt-Ohmmeter (DVOM)
4. Remote Starter Switch
5. Breakout Box (BOB) With 2.3L DP DIS Overlay
6. High Voltage Spark Tester (A spark plug with a broken side electrode is not sufficient to check for spark and may lead to incorrect results.)
7. Tachometer
8. Inductive Type Timing Light (DO NOT use "advance knob", if equipped, as it will not work correctly with DIS Ignition Systems.)
9. Test Light (LED Type) Or Logic Probe (LED Type)

PINPOINT TESTS A through F are intended to diagnose hard faults. Intermittent failures may be difficult to diagnose using these procedures.

A Breakout Box (BOB) connected to DIS diagnostic cable is referred to as DIS BOB. If a second BOB is connected to the ECA vehicle harness connector it is referred to as ECA BOB. This test setup allows testing of DIS components and vehicle harness circuits.

Circuits are identified in all capitals, example: IGND=Ignition Ground. Manufacturer's BOB overlay identification is in brackets, example: (J2)=IGND (J2). This indicates test terminal number or circuit identification number.

Note. Unless specified otherwise in a specific test step, all voltage and resistance tests of DIS ignition system are performed at the BOB connected to the DIS diagnostic cable.

Note. When performing PINPOINT TEST procedures for the 2.3L DIS (Ranger) system (Scheme 114)and (Scheme 115).

Scheme 114

Scheme 115

2.3L RANGER DIS PINPOINT TEST INDEX

PINPOINT TEST A

PINPOINT TEST B

PINPOINT TEST C

PINPOINT TEST D

PINPOINT TEST E

PINPOINT TEST F

Following equipment should be used in these test procedures.

1. EDIS Diagnostic Cable (Rotunda 007-00059)
2. Spark Tester (Neon Bulb Type)
3. Volt-Ohmmeter (Rotunda 007-00001)
4. Remote Starter Switch
5. 2 Breakout Boxes (BOB), For DIS (DIS BOB) And ECA (ECA BOB)
6. Spark Tester (D81P-6666-A Or equivalent)
7. Inductive Timing Light
8. Test Light (LED Type) Or Logic Probe (LED Type)

When making measurements on a wiring harness, both a visual inspection and a continuity test should be performed. Inspect terminal connector pins for damage and corrosion, when directed to remove a connector.

1. Spark timing adjustments are not possible. Timing is controlled by the EDIS module with input from the ECA.
2. When checking voltage drop to GROUND, circuit must have a voltage drop of less than one volt.
3. Battery voltage (VBAT) is any voltage reading within 2 volts of actual battery voltage.
4. Spark timing will vary at idle due to feedback spark strategy used to control idle speed.
5. DO NOT connect positive lead of EDIS diagnostic cable to battery or connect cable to VR sensor until directed to.
6. SAW and IDM signal detectors in EDIS diagnostic cable will not work unless diagnostic cable battery leads are connected to battery.
7. When using DVOM to measure DC voltage always connect positive lead to BOB terminal A(+) and negative lead to A(-).

Note. When using PINPOINT TEST procedures for the 4.0L EDIS (Aerostar, Explorer, Navajo & Ranger) system (Scheme 117)& see scheme 21.

Scheme 116

Scheme 117

4.0L EDIS PINPOINT TEST INDEX

DO NOT connect ECA to EDIS diagnostic cable. The 60-pin connector on this harness may be connected to a Breakout Box (BOB) only. If ECA is connected to EDIS diagnostic cable it may be damaged. Some tests may require a second BOB (ECA BOB) to be connected to ECA 60-pin connector. When a second BOB is used, ECA should be disconnected at all times. Never connect ECA to BOB when performing EDIS diagnostics.

DO NOT bring a fluorescent trouble light (drop light) close to vehicle ignition system wiring. If key is on and VR sensor is disconnected, light may cause EDIS module to fire ignition coil.