1986 Volvo 245 Base, AutomaticFACTORY OEM SERVICE PROCEDURE

Co Adjustment Using Co Meter

  1. Connect tachometer- stroboscopic timing light/analyser CO-meter. Warm-up engine and run at 1500 rpm.
  2. Check idle speed.
    NOTE: Engine should be warmed-up until radiator thermostat opens and then for a further 10 minutes.

    Ground red-white wire from test point to close air control valve. Switch off A/C as applicable. Adjust engine speed w/idle adjustment screw to 700 rpm. Disconnect ground from test point. Engine should increase to 750 +/- 20 rpm. If values are incorrect check/adjust throttle controls. See THROTTLE VALVE, SWITCH, LINKAGE ADJUSTING

  3. Check/adjust ignition setting. Idle speed fluctuations can affect ignition setting. Make sure that fluctuations are not greater than 25 rpm. If greater, check air control valve for blockages. Ignition setting should be 12°BTDC at idle. Adjust setting by turning distributor body.
  4. Disconnect Lambda sond. Check CO-content, it should be 0.4-0.8 percent.
  5. Adjusting CO-content. CO should only be adjusted after all possible faults have been checked/rectified. Remove seal and turn off engine. Drill two 2mm (0.08") holes in plug. Withdraw plug w/circlip pliers. Start engine. CO should be adjusted until test diode begins to flash. Turning the adjustment screw counterclockwise reduces the CO and turning clockwise increase CO. 15 turns is the range for the adjustment screw. Always use a new seal CO adjustment screw plug. Push plug into position.
  6. Connect Lambda sond. Turn off engine. Disconnect test equipment. Instal plug in exhaust pipe.
    WARNING: Adapter can be extremely hot.
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Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.