F 150 2WD Pickup V8-351 5.8L Lightning (1993)
Oil Pressure Gauge: Description and Operation
OPERATION
Constant Voltage Regulator Gauge System (CVR)
This oil pressure indicating system incorporates an instrument voltage regulator, electrical oil pressure gauge and a sending unit which are
connected in series. The sending unit consists of a diaphragm, contact and a variable resistor. As oil pressure increases or decreases, the diaphragm
actuates the contact on the variable resistor, which in turn controls current flow to the gauge. When oil pressure is low, resistance of the variable
resistor is high, which restricts current flow to the gauge, indicating low oil pressure. As oil pressure increases, resistance of the variable resistor is
lowered, permitting increased current flow to the gauge, which increases the gauge reading.
Fig. 8 Magnetic Guage
MAGNETIC GAUGE SYSTEM
The magnetic gauge movement consists of three primary coils, one of which is wound at a 90° angle to the other two. The coils form a magnetic
field which varies in direction according to the variable resistance of the sender unit which is connected between two of them. A primary magnet
which is attached to a shaft and pointer rotates to align to this primary field resulting in pointer position. The bobbin/coil assembly is pressed into a
metal housing which is attached to the instrument cluster. These gauges require no adjustments, calibrations or maintenance. This gauge system
does not use an IVR.