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Spark Control System Honda Civic III

Testing & Diagnostics 2 illustrations ~630 words

DESCRIPTION & OPERATION

All engines have ignition control systems to lower emission levels, maximize fuel economy and improve engine performance. The system is designed to advance and retard ignition timing as necessary.

All models use a distributor advance with 2 separate vacuum diaphragms. Diaphragm A operates on intake manifold vacuum. Diaphragm B operates on intake manifold vacuum via an inline thermovalve, vacuum control solenoid valve or cold advance solenoid valve. During cold engine operation, thermovalve B allows vacuum to enter diaphragm B to improve engine performance.

FEDERAL 1500 HF (COLD ENGINE) TEST

  1. Ensure engine coolant temperature is below 113°F (45°C). Disconnect vacuum hose No. 2 from vacuum advance diaphragm B. Connect vacuum gauge to hose.
  2. Start engine and check for vacuum at idle. If there is vacuum, proceed to «HOT ENGINE TEST»(/honda/civic/iii-1983-1987/remont/testing-diagnostics/#spark-control-system__hot-engine-test) . If there is no vacuum, check for voltage between cold advance solenoid valve terminals (Red/White wires) of control box No. 1 connectors.
  3. There should be battery voltage. If there is battery voltage, replace cold advance solenoid valve and retest. If there is no voltage, check speed sensor and thermosensor B.
  4. Check for voltage at control unit connector (Blue wire) with ignition on. There should be voltage. If no voltage, check Blue wire between ignition coil and control unit.
  5. Check for voltage at control unit connector (Black/Yellow wire) with ignition on. There should be voltage. If no voltage, check fuse and wiring. Check Black wire for continuity between control unit and ground. There should be continuity.

Ignition Timing Controls (CRX Si Models). Scheme 13

Scheme 13: Ignition Timing Controls (CRX Si Models)
Scheme 13: Ignition Timing Controls (CRX Si Models)

EXCEPT FED. 1500 HF (COLD ENGINE) TEST

  1. Ensure engine coolant temperature is below 59°F (15°C). Disconnect vacuum hose No. 2 from vacuum advance diaphragm B. Connect vacuum gauge to hose.
  2. Start engine and check for vacuum at idle. If there is vacuum, proceed to «HOT ENGINE TEST»(/honda/civic/iii-1983-1987/remont/testing-diagnostics/#spark-control-system__hot-engine-test) . There sould be vacuum. If there is no vacuum, replace thermovalve B and retest.

Ignition Timing Controls All models except CRX Si. Scheme 14

Scheme 14: Ignition Timing Controls All models except CRX Si.
Scheme 14: Ignition Timing Controls All models except CRX Si.

HOT ENGINE TEST

  1. Disconnect vacuum hose No. 2 from vacuum advance diaphragm B. Connect vacuum gauge to hose. Connect tachometer. Start engine and run at idle. Check for vacuum at vacuum hose No. 2. If there is no vacuum, proceed to step 5).
  2. If there is vacuum, check the following: On all models except Fed. 1500 HF, replace thermovalve B and retest. On Fed. 1500 HF models, check for voltage between cold advance solenoid valve terminals (Red/White wires at control box No. 1 connectors).
  3. If there is no voltage, replace cold advance solenoid valve and retest. If there is voltage check speed sensor and thermosensor B. Check for voltage at control unit connector (Blue wire) with ignition on. There should be voltage. If no voltage, check Blue wire between ignition coil and control unit.
  4. Check for voltage at control unit connector (Black/Yellow wire) with ignition on. There should be voltage. If no voltage, check fuse and wiring. Ensure Black wire between control unit and ground has continuity.
  5. Attach a hand vacuum pump to both vacuum advance diaphragms using a "T" fitting. Plug vacuum advance hoses. Pinch off hose to vacuum diaphragm B. Start engine and apply 16 in. Hg vacuum. Ensure timing advances and vacuum remains steady. If not, replace advance diaphragm and retest.
  6. If timing did not advance, check breaker plate for freedom of movement. Repair or replace as necessary. If breaker plate moves freely, replace vacuum advance and retest.
  7. Released pinched vacuum hose and apply 16 in. Hg vacuum. Timing should advance more than in step 5) and remain steady. If timing advances more than in step 5), system is okay. If timing does not advance more than in step 5) or will not stay advanced, replace vacuum advance and retest.

See also:
• HOT ENGINE TEST

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