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.
Detonation (Knock) Retard Operation
The 929S and turbocharged models use an ignition retard system consisting of knock sensor(s) and knock control unit. The knock sensor detects engine detonation (knocking) in the engine and sends a signal to knock control unit. This signal is modified by the knock control unit and sent to the ECU.
Timing can be retarded up to 6 degrees, depending upon amount of knocking. On MX-6 turbo and 626 turbo models, knock control unit also controls turbocharger wastegate solenoid valve, lowering turbo boost pressure up to 2.2 psi during knock conditions.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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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