CO Level Check

Note:
The engine MUST be at normal operating temperature 80 - 90 degrees C (180 - 190 degrees 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 (MD189445). If the CO is still greater than 1.2%, refer to the 1986 Truck Service Manual for troubleshooting procedures contained in section 14.