Retard Components (Capri Turbo)

Positive pressure to the vacuum advance cylinder on the distributor retards ignition timing. The Powertrain Control Module (PCM) also retards ignition timing when it receives a signal from Knock Sensor (KS) and related circuitry.

1) Disconnect and plug hoses at distributor. Connect timing light. Start engine. Determine and record ignition timing. Tap intake plenum with plastic mallet while monitoring ignition timing. If timing retards, Knock Control (KC) circuitry is okay. If timing does not retard, go to next step.

2) Unplug KC sensor service connector, located near PCM. Tap intake plenum with plastic mallet while observing ignition timing. If timing does not retard, go to step 4). If timing retards, go to next step.

3) Reconnect KC service connector. Tap intake plenum with plastic mallet while monitoring ignition timing. If ignition timing retards, replace knock controller. If ignition timing does not retard, go to next step.

4) Unplug KC service connector. Temporarily install known good knock sensor. Tap intake plenum with plastic mallet while monitoring ignition timing. If ignition timing retards, replace knock sensor. If ignition timing does not retard, go to next step.

5) Turn ignition off. Connect BOB. Ensure vehicle power (VPWR) and ground wires to knock sensor are okay. Check all knock sensor wiring for shorts or opens. If wiring is okay, replace knock sensor.