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.
1966 Cadillac
Disconnect parking brake vacuum line at vacuum diaphragm, connect vacuum gauge to line. With idle air by-pass screw set 1 1/2 turns out from fully seated position, and each idle mixture screw set 2 turns out from lightly seated position, warm up engine to normal operating temperature with transmission in neutral. With engine at normal operating temperature (choke valve fully open and fast idle inoperative), place transmission selector lever in either "DR" position, make certain that torque converter stator in correct position (disconnect pink wire from contact on transmission downshift switch and connect to white wire fitting to activate stator switch). Turn air conditioning ON and make certain that hot idle compensator valve is closed, adjust engine idle speed to correct RPM (see Specifications ) by turning idle air by-pass screw on throttle body. Adjust one idle mixture adjusting screw by turning screw clockwise until engine speed reaches maximum RPM, continue to turn screw in until engine speed falls off 20 RPM (lean idle speed fall off), finally turn screw out 1/4 turn. Adjust second idle mixture adjusting screw in same manner. Readjust engine idle speed and repeat idle mixture screw adjustment, then install air cleaner and recheck idle speed. Restore transmission downshift switch connections and reconnect parking brake vacuum cylinder line.
NO RELATED
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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.