The 1984 and later 6.2L California applications use an internal idle spring, which controls the gap between the sleeve and the washer. (Figure 4-74). The close tolerance will result in a more accurate input to the engine throttle position sensor, which regulates the exhaust gas recirculation and exhaust pressure regulator functions.
Now for a look at the operation of the assembly that controls the engine speed at low idle and high speed. The Min-Max governor. Illustrated here (Figure 4-70) are the main components of the governor. They are the governor weights, the governor arm, the low idle spring, the idle spring guide, the main governor spring,… Read More »
All pumps are equipped with a Housing Pressure Cold Advance solenoid. (Figure 4-67). This component has been designed to allow more advance during engine warm-up. It consists of a solenoid assembly and a ball check return connector, both in a redesigned governor cover. The electrical signal which controls the operation of the solenoid is generated… Read More »
A new head locating screw (#24566) with nylon filter has been introduced to prevent contaminants from reaching the advance piston area. See Figure 4-66. The filter is installed into the body of the screw, the end of which is crimped over. The screw is only available as an assembly, as shown on the right, and… Read More »
See Figure 4-65. The advance piston orifice screw has been eliminated, and the orifice is now machined into the piston. The orifice size in 1984 and later is .030 in. 1982-83 orifice size was a .040 in. orifice screw. Stanadyne part #24433 (2443405).
As with the previous advance system, the rotor’s force is transferred to the cam ring during injection. This force continually urges the piston toward the retard position. However, an opposing force is supplied by transfer pump pressure acting on one end of the servo advance piston. (Figure 4-62). The position of the servo valve in… Read More »
A second light load advance system, shown in Figure 4-61, is available for automotive applications that use min-max governing. In addition to the normal speed advance, light load advance is furnished as a function of throttle angle. The mechanical light load advance system is used on automotive pumps. It relies on two systems to provide… Read More »
As noted previously, inlet metered pumps characteristically retard the start of pumping at light loads. To correct this condition, several forms of light load advance have been developed, two of which are described below. • The first of these, used in speed advance (used only in the 78-81 5.7L diesel), uses a smaller diameter advance… Read More »
The inlet metered DB2 pump (Figure 4-60) has a pumping period with a variable beginning and a constant ending. That is, at minimum throttle positions the metering valve is only open a small amount, so the plungers only move a small amount. And the rollers have to ride a great distance up the cam ramp… Read More »
When the pump is operating, the force required to displace the plungers inward plus the momentum of the rotor assembly transmitted by the rollers, produces the cam loading force. This tends to turn the cam in the direction of rotor rotation. (Figure 4-59). This movement retards the pump’s timing. This cam loading plus spring force… Read More »