The oil pressure sensor functions by the opening and closing of the contact points in the sensor. This action is controlled by the rising and falling oil pressure, which is dependant upon the oil temperature and engine speed.
The sensor closes when the oil pressure drops to between 4-7 psi (28-48 kPa).
This test should be performed if the oil pressure gauge does not show correct oil pressure and the cause is thought to be the sender.
Turn the ignition to the
position (do not start the engine). Observe the oil pressure gauge or dash indicator light.
- If the gauge reads between 0-30 psi (0-207 kPa), proceed to Step 2.
- If the gauge reads 0 or below or the indicator light does not come on, the problem lies in the wiring, to the gauge or indicator.
Disconnect the oil pressure switch/sender and short the lead to an engine ground.
- If the gauge indicates approximately mid-scale or slightly above mid-scale, replace the oil pressure switch/sender. Retest the system after repairs are complete.
- If the gauge does not perform as described above, the problem lies in the wiring, the gauge itself or the instrument cluster.
REMOVAL & INSTALLATION
See Figures 1 and 2
The pressure switch type unit used with the indicator lamp system is not interchangeable with the variable resistance type unit used with the gauge system. Installation of the wrong part will result in an inoperative oil pressure indicating system and a damaged switch unit or gauge.
- Disconnect the negative battery cable.
- Locate the sensor at the side of the engine block.
- Disconnect the wire at the sending/switch unit.
- Place a drain pan below the sensor to catch any oil which may spill out.
- Remove the sending unit from the engine block.
- Wrap the threads of the new sending unit with Teflon® tape and carefully screw it into place. Make sure not to cross-thread the sending unit.
- Tighten the sending unit to 15 ft. lbs. (20 Nm).
- Attach the wire to the sending unit.
- Connect the negative battery cable.