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Home/Mercury/Topaz/Mercury Topaz II (1987-1994)/Repair manual/Engine Controls - Tests W/codes - 2.3l/NO START
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NO START Mercury Topaz II

Engine Controls - Tests W/codes - 2.3l 2 illustrations ~1298 words

NO START

CAUTIONStop this test at first sign of a fuel leak. Do not allow smoking or an open flame in the vicinity of the vehicle during these tests.

Note. Enter this CIRCUIT TEST only when QUICK TESTS have been successfully completed and the engine is still a no start, or when directed here from another test or chart.

Note. This test is intended to diagnose only the following EEC-IV ignition systems and circuits

  1. Thick Film Ignition (TFI) Systems
  2. TFI Systems With Closed Bowl Distributors (CBD) and Cowl Mounted TFI Modules
  3. Distributorless Ignition Systems (DIS)
  4. Spark (ECA Controlled)
  5. Wiring Harness Circuits (PIP, SPOUT, IGN GND, VPWR)
  6. ECA

Circuit Test A: DIS Module Circuits. Scheme 4

Scheme 4: Circuit Test A: DIS Module Circuits
Scheme 4: Circuit Test A: DIS Module Circuits
Test Pin No.Wire Color
Pin 56Dark Blue
Pin 36Yellow/Light Green
Pin 16Black/Orange

TFI/DIS TEST PIN IDENTIFICATION

To prevent replacement of good components, be aware that the following non-EEC related areas and components may be at fault

  1. Fuel Quality & Quantity
  2. Ignition (General System Condition)
  3. Ignition (TFI or EDIS/DIS Module)
  4. Engine Mechanical Components
  5. Starter & Battery Circuits
  6. Dual Hall Sensor
  7. Distributor
  8. Camshaft Sensor (CID)
  9. Crankshaft Hall Sensor (PIP)
  10. Ignition or EDIS/DIS Coil

1) Starting System Try to start engine. If vehicle is equipped with DIS, go to TEST N, step 1. If engine does not crank, check vehicle starting and charging systems. If engine cranks, go to next step.

2) Checking VREF Signal at TPS Ensure fuel pump inertia switch is set (button pushed in). Turn key off and wait 10 seconds. Set DVOM on 20-volt scale and disconnect Throttle Position Sensor (TPS). Turn key on, leaving engine off (KOEO). Measure voltage at TPS harness connector between VREF and SIG RTN. If reading is less than 4 volts or more than 6 volts, go to TEST C, step 1. If reading is between 4 and 6 volts, reconnect TPS and go to next step.

TPS Harness Connectors. Scheme 5

Scheme 5: TPS Harness Connectors
Scheme 5: TPS Harness Connectors

3) Check For Spark At Plugs Disconnect any spark plug wire and connect spark tester between plug wire and engine ground. Crank engine and check for spark. If spark was present and consistent, connect spark plug wire and go to step 12. If there is no spark, connect spark plug wire and go to next step or to step 5 for vehicles equipped with DIS.

4) Check For Spark at Coil Remove high tension coil wire from distributor and install spark tester. Check for spark while cranking engine. If spark exists, connect coil wire and service or repair TFI ignition system. If no spark exists, connect coil wire and go to next step.

5) Check Ignition Circuit Ground Continuity Turn key off and wait 10 seconds. Disconnect and inspect ECA 60-pin connector. Install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale and disconnect TFI module or DIS module (pins No. 7-12). Measure resistance between test pin No. 16 at the breakout box and TFI, Hall Sensor, or DIS harness connector IGN GND circuit. If reading is more than 5 ohms, repair open in circuit and repeat QUICK TEST. If reading is less than 5 ohms, go to next step.

6) Isolating SPOUT Circuit Fault Install breakout box. Connect TFI module or DIS module (pins No. 7-12). Connect ECA to breakout box. Set breakout box timing switch to DISTRIBUTOR or DIST position. Try to start vehicle. If vehicle starts, move timing switch to COMPUTED position and go to step 10. If vehicle does not start, go to next step.

7) Check SPOUT Signal With KOEO, install breakout box and connect ECA. Move breakout box timing switch to COMPUTED position. Set DVOM on 20-volt scale and measure voltage between test pin No. 36 at the breakout box and battery negative post while cranking engine. If voltage is between 3 and 6 volts, EEC system is NOT at fault. Diagnose TFI or DIS ignition system. If voltage is less than 3 volts or more than 6 volts, go to next step.

8) Check SPOUT & PIP Circuits For Shorts Turn key off and wait 10 seconds. With breakout box installed, disconnect ECA. Disconnect TFI module. Set DVOM on 200-k/ohm scale.

On SPOUT circuit, measure resistance between test pin No. 36 (SPOUT) and test pins No. 16, 20, 40, 46, and 60 for short to ground. Measure resistance between test pin No. 36 and test pins No. 26, 37 and 57 for short to power (VPWR). Measure resistance between test pins No. 36 and 56 for short to PIP.

On PIP circuit, measure resistance between test pin No. 56 (PIP) and test pins No. 16, 20, 40, 46, and 60 for short to ground. Measure the resistance between test pin No. 56 and test pins No. 26, 37 and 57 for short to power.

If any reading is less than 10 k/ohms, repair short in harness and repeat QUICK TEST. If engine still does not start, go to next step. If all readings are 10 k/ohms or more, go to next step.

9) Isolating Shorts In ECA Turn key off and wait 10 seconds. With breakout box installed, connect ECA, but leave TFI or DIS disconnected. Set DVOM on 200-k/ohm scale.

On SPOUT circuit, measure resistance between test pin No. 36 (SPOUT) and test pins No. 37 and 57 for short to power. Measure resistance between test pin No. 36 and test pins No. 40 and 60 for short to ground.

On PIP circuit, measure resistance between test pin No. 56 (PIP) and test pins No. 37 and 57 for short to power. Measure resistance between test pin No. 56 and test pins No. 40 and 60 for short to ground.

If any reading is less than 500 ohms, replace ECA and repeat QUICK TEST. If all readings are greater than 500 ohms, connect TFI and go to next step.

10) Check PIP Signal With key off, install breakout box. Set DVOM on 20-volt scale. Measure voltage between test pins No. 56 and 16, while cranking engine. If reading is between 3 and 7 volts, remove breakout box. Replace ECA and repeat QUICK TEST. If reading is less than 3 volts or more than 7 volts, go to next step.

11) Check Continuity of PIP Circuit Install breakout box, turn key off and wait 10 seconds. Set DVOM on 200-ohm scale. Disconnect ECA and TFI. Measure resistance between test pin No. 56 and TFI connector PIP circuit. If reading is 5 ohms or more, repair open PIP circuit and repeat QUICK TEST. If readings is less than 5 ohms, go to next step.

12) Verify SPOUT Signal - Turn key off and wait 10 seconds. Disconnect ECA 60-pin connector and inspect for damaged pins, corrosion, or loose wires. Repair as necessary. Install breakout box and connect ECA. Ensure breakout box timing switch is in COMPUTED position. Set DVOM on 20-volt scale and measure voltage between test pin No. 36 and test pins No. 40 and 60 while cranking engine. If reading is between 3 and 6 volts, go to step 20. If reading is less than 3 volts or more than 6 volts, return to step 8.

Note. There is a break in the step numbering sequence at this point, skipping from step 12 to step 20. Break is due to previous chart references to these testing procedures. No test procedures have been omitted.

CAUTIONUse safety precautions when working on fuel system. No smoking or open flame. If fuel starts leaking, immediately turn key off.

20) Fuel Pump Check Connect pressure gauge to vehicle. Note initial pressure reading. Pressurize fuel system by turning key on for one second and observe pressure gauge. Turn key off, and wait 10 seconds. Repeat sequence 5 times. If pressure increased, go to TEST S, step 1 for PFI fuel injected engines. If pressure did not increase, go to next step.

21) Inertia Switch Resistance Check Turn key off. Locate fuel pump inertia switch and ensure push button on switch is pushed down in the ON or CLOSED position. Set DVOM on 200-ohm scale. Measure resistance of switch. If resistance is greater than 5 ohms, replace switch. If resistance is less than 5 ohms, go to TEST J, step 1.