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Home >> Ford >> 1990 >> Bronco II RWD, Standard, M5OD-R1 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - System/Component Tests >> Ignition System >> Pinpoint Test C
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Pinpoint Test C

  1. Check For Left Side Spark With KOER  Start engine and using spark tester, check for spark at each left spark plug wire. If spark is present at any left spark plug wire, go to step 2. If spark is not present, go to PINPOINT TEST D, Step 1.
  2. Check IDM With KOER  With key off, install DIS diagnostic cable module tee (pin Nos. 7-12) to DIS module. Connect DIS diagnostic cable to BOB. Use 2.3L DP DIS overlay. Connect LED test light positive lead to IDM (J4) and negative lead to BAT (J60). Start engine and observe test light. If test light blinks continuously, go to step 3. If test light does not blink, go to step 4.
  3. Check IDM To ECA Continuity To ECA  With key off, disconnect ECA. Crank engine and observe test light. If test light blinks continuously, replace ECA. ECA does not respond to IDM input. Remove test equipment and reconnect all components. Clear Continuous Memory Codes and rerun Quick Test. If test light does not blink, go to step 4.
  4. Isolate ECA & Check IDM Circuit During Cranking  With key off, disconnect ECA. Crank engine and observe test light. If test light blinks continuously, replace ECA. The ECA is shorting IDM. If test light does not blink, go to step 5.
  5. Check IDM For Short To Power  With key off, and disconnect HEGO sensor. Disconnect DIS diagnostic cable module tee (pin Nos. 7-12) from DIS module. Set DVOM on 20-k/ohm scale. Measure resistance between IDM (J4) and VBATD (J5). If resistance is less than 10 k/ohms, check connectors and service or replace harness. IDM is shorted to VBAT. Remove test equipment and reconnect all components. Clear Continuous Memory Codes and rerun Quick Test. If resistance is 10 k/ohms or more, go to step 6.
  6. Check IDM For Short To Ground  With key off and disconnect diagnostic cable connector from DIS module (pin Nos. 7-12). Set DVOM on 20-k/ohm scale. Measure resistance between IDM (J4) and BAT (J60). If resistance is 10 k/ohm or less, check connectors and service or replace harness. IDM is shorted to ground. Remove test equipment and reconnect all components. Clear Continuous Memory Codes and rerun Quick Test. If resistance is 10 k/ohm or more, replace DIS module. IDM is shorted in DIS module. Remove test equipment and reconnect all components. Clear Continuous Memory Codes and rerun Quick Test.


  1. Check Base Ignition Timing  With ignition off, install EDIS diagnostic cable to BOB, EDIS module, and coil pack. Do not connect VR sensor tee. Use EDIS "6" overlay (if available). Connect EDIS diagnostic cable negative and positive leads to battery. Set EDIS diagnostic cable box switch to "4/6 cylinder" position. Connect timing light (must be EDIS/DIS compatible). Start engine and allow it to warm up. If timing is 10+/-2 degrees BTDC when EDIS diagnostic cable SAW button is pushed, go to step 2. If timing is not as specified, proceed to step 8.
  2. Check For Advance Spark Angle  If engine timing is greater than 15 degrees BTDC when diagnostic cable SAW button is released, EDIS Ignition System is okay. Go to TESTS W/O CODES article in the ENGINE PERFORMANCE Section for further driveability symptom diagnosis. If timing is not as specified, go to step 3.
  3. Check SAW At EDIS Module  With ignition off, set DVOM on 20-volt DC scale. Start engine and measure voltage between EDIS diagnostic cable SAW DETECTOR (21) and BAT (7) at BOB. If DC voltage reading is 5-7 volts, replace EDIS module. SAW input to EDIS module is okay but no spark advance is present. Remove test equipment and reconnect all components. Clear Continuous Memory Codes and rerun Quick Test. If DC voltage is not 5-7 volts, proceed to step 4.
  4. Check For SAW Short In EDIS Module  Isolate EDIS Module With ignition off and ECA connected, set DVOM on 20-volt DC scale. Push EDIS diagnostic cable SAW button at EDIS diagnostic cable connector to BOB. Start engine and measure voltage between SAW DETECTOR (21) and BAT (7) at BOB. If DC voltage reading is 5-7 volts, replace EDIS module. SAW circuit is shorted in EDIS module. Remove test equipment and reconnect all components. Clear Continuous Memory Codes and rerun Quick Test. If DC voltage is not 5-7 volts, proceed to step 5.
  5. Check For SAW Short To Ground In Harness  With ignition off, disconnect ECA. Disconnect EDIS module from EDIS diagnostic cable module tee. Leave EDIS diagnostic cable connected to vehicle harness connector. Disconnect HEGO connector. Set DVOM on 200-ohm scale. Measure resistance between SAWE (45) and BAT (7) at BOB. If resistance is less than 100 ohms, repair short circuit. Remove test equipment and reconnect all components. Clear Continuous Memory Codes and rerun Quick Test. If resistance is 100 ohms or more, reconnect HEGO sensor and go to step 6.
  6. Check For SAW Short To VBAT In Harness  With ignition off, and ECA disconnected, set DVOM on 20-volt DC scale. With KOEO, measure voltage between SAWE (45) and BAT (7) at BOB. If DC voltage reading is less than .5 volt, repair short circuit. SAW is shorted to VBAT. Remove test equipment and reconnect all components. Clear Continuous Memory Codes and rerun Quick Test. If voltage is .5 volt or more, go to step 7.
  7. Check For SAW Open  With ignition off and ECA disconnected, connect ECA BOB to ECA harness connector. Set DVOM on 200-ohm scale. Measure resistance between SAWE (45) at BOB and terminal No. 36 at ECA BOB. If resistance is less than 5 ohms, replace ECA. SAW is not being transmitted by ECA. Remove test equipment and reconnect all components. Clear Continuous Memory Codes and rerun Quick Test. If resistance is not as specified, repair open circuit. Remove test equipment and reconnect all components. Clear Continuous Memory Codes and rerun Quick Test.
  8. Inspect VR Sensor/Trigger Wheel  If VR sensor or trigger wheel is damaged, loose or misaligned, replace or repair components as required. Remove test equipment and reconnect all components. Clear Continuous Memory Codes and rerun Quick Test. If trigger wheel and VR sensor are not damaged or loose, replace EDIS module. Module cannot control timing. Remove test equipment and reconnect all components. Clear Continuous Memory Codes and rerun Quick Test.
CAUTION: Never connect ECA to ECA BOB when performing EDIS diagnostics unless directed to do so.
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