CO Level Checking

Note:
Engine MUST be at normal operation temperature 85 to 95~ C (185 to 205~ F).
1. Insert the exhaust analyzer probe into the tailpipe.

2. Run the engine at 2,500 RPM. for approximately 30 seconds.

3. Check the tailpipe CO after 30 seconds and record the reading at 2,500 RPM.

4. If the CO reading is greater than 1.2% at 2,500 RPM, visually check the new Jet Mixture Solenoid Valve installation for misalignment. If the Jet Mixture Solenoid Valve is correctly installed, replace it with another new green Jet Mixture Solenoid Valve. If the CO is still greater than 1.2%, refer to the 1986 Truck Service Manual for troubleshooting procedures which begin in Section 14.