Trace your hoses it should be in the center of the firewall way up under the wireing harness there is a steel line with the port right in the middle.
The 1991 VW Jetta low pressure port can be found on the air conditioning compressor. There are two ports, the low pressure port will be labeled as such.
under the battery
Larger hose from the air compressor
The oil pressure sensor is located behind the engine just to the right of the coil packs
The low pressure cap is in the front of the engine compartment. Stand facing the engine and to the left just behind the radiator U will see an air conditioning line. There will be a black cap that should have an L on it but it might be worn off. That is your low pressure cap.
In a 1991 3.3l the oil pressure switch is located beside the oil filter
In the throttle body.
Follow the rail line that runs to the injectors. You will find the pressure regulator.
The 1991 Acura Legend does not have an oil temperature sensor. It does have an oil pressure sensor. The oil pressure sensor will be located on the left-hand side of the engine.
Oil Pressure Sender and SwitchFord Ranger/Explorer/Mountaineer 1991-1999 Check Related Links below.
The expansion valve is located in and with the evaporator, inside the evaporator case. This case is a somewhat square, plastic enclosure located directly behind the glove box on this vehicle.
it is in the side of the oil pan