Q: What is the purpose of the cruising speed control system on Buick Skylark,Oldsmobile Omega and Pontiac Phoenix?
A: This cruising speed control system is optionally available on certain models and allows the driver to maintain a constant highway speed without the necessity of continual adjustment of foot pressure on the accelerator pedal. The system employs a servo unit connected to the intake manifold, a speedometer cable-driven regulator and various switches. An override capability is built in. Any malfunction in the performance of the system should first be checked out by inspecting the fuse, the security of the leads and terminals, and the vacuum pipes and connections. The following adjustments should then be checked and if necessary altered to conform to those specified. The servo operating rod which connects to the carburetor throttle linkage should be adjusted. The regulator can be adjusted by turning the orifice tube in or out (never remove it as it cannot be re-installed). If the vehicle cruises below the engagement speed, screw the orifice tube out. If the vehicle cruises above the engagement speed, screw the orifice tube in. Each¾ turn of the orifice tube will change the cruise speed by about 1 mph.Tighten the locknut after each adjustment. The brake release switch contacts must open when the brake pedal is depressed between ¼ and ½-in measured at the pedal pad. The vacuum valve plunger must clear the pedal arm when the arm is moved A inch measured at the switch. The column mounted engagement switch is non-adjustable, and is serviced only as part of the complete turn signal lever assembly. Faulty components should be replaced as complete assemblies after disconnecting electrical leads, vacuum hoses and control cables from them as necessary.