Engine Mechanical problem
1987 Nissan Patrol/Safari 6 cyl Four Wheel Drive Manual 390000 miles
I just noticed that the oil gauge is not reading (ie below zero). It has only been like this for past few days (it normally sits at ~mid-scale). The car seems to be running OK otherwise (ie not heating up, etc).
Question : Is it likely to be the gauge, or the sensor, or maybe it actually has no oil pressure (could it keep working? I have driven ~100kms like this).
I put a voltmeter across the oil sensor, but it always reads +12V. Resistance of Sensor appears to be 100 ohms when motor not running, and open-circuit when motor is running.
I substituted a 2k ohm variable resistor for the sensor, and can vary the voltage across it between 0 and 12V, but there is no change in the gauge on the dashboard (for any voltage setting).
I am totally confused.
Q1: What resistance, or voltage should I see across the oil pressure sensor? (When motor is running, and not running)
Q2: Why is the gauge not registering anything with the variable resistor?
Do I have two faults?
There does not seem to be a blown fuse anywhere.
This is the first Diesel engine I have worked on. It appears to have many differences from petrol engines - in totally unpredictable areas.