Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Engine Co/HC Inspection: Co/HC: Inspection
This check is used only to determine whether or not the idle CO/HC complies with regulations.
- Initial conditions.
- Engine at normal operating temperature
- Air cleaner installed
- All pipes and hoses of air induction system connected
- All accessories switched OFF
- All vacuum lines properly connected
- SFI system wiring connectors fully plugged
- Ignition timing checked correctly
- Transmission in neutral position
- Tachometer and CO/HC meter calibrated by hand
- Start engine.
- Race engine at 2,500 rpm for approx. 180 seconds.
- Insert CO/HC meter testing probe at least 40 cm (1.3 ft) into tailpipe during idling.
- Immediately check CO/HC concentration at idle and/or 2,500 rpm.NOTE:
When doing the 2 mode (2,500 rpm and idle) test, follow the measurement order prescribed by the applicable local regulations.
Use the Manual With the Right Hardware
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When to See a Mechanic
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.
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