Puzzle With My Cat Today
Discussion
If anyone can explain this issue I would be grateful.
I have a dry sumped 2.3 Duratec. I took the Cat out earlier today, having not used it for a month or so. I had been driving for about an hour in typical A road conditions when I became stationary due to the tail back into Salisbury. The Stack oil warning light flashed on and I noticed the pressure had dropped to single figures at idle. After the near heart attack I gave it a gentle blip or two and it increased to the teens, it's idle norm is 29-30. As I crawled in the traffic I kept a careful eye and again it would drop at idle, mostly to around 12-15. I was minded to pull over but aside of the fact that there was no room to do so all other vital signs were normal and I kept telling myself that it was more likely a fault with the reading than the pressure. As I cleared the city and picked up a bit of dual carriageway the pressure came up to 50/55 at 3,000 rpm where I would have expected to see 75/80. At that point I was getting more concerned, pound notes were going through my mind and I was thinking towards finding a suitable stopping point. Whilst pondering the problem I switched off the heater fan, the day was starting to warm up, the moment I did so the pressure sprang up 20psi to it's norm of about 80 at 3,250 rpm. Thinking it was just a coincidence I clicked the fan on again and accordingly down went the pressure by 20. I repeated my on off, on/off experiment a few times since with the same result.
And so to the puzzle, why is my heater fan having the effect of reducing the oil pressure reading by 20? Fault with the Stack dash maybe, perhaps an earthing fault more generally or what? I thought maybe the it was due to a voltage reduction so I tried flicking the lights on and off a few times, this had no effect on the pressure reading but it did generate a wave from someone going the other way!
And yes before anyone says it, I know I should be not so much of a lightweight to have needed the heater on in the first place but in my defence it was a bit parky at 0730 this morning!
I have a dry sumped 2.3 Duratec. I took the Cat out earlier today, having not used it for a month or so. I had been driving for about an hour in typical A road conditions when I became stationary due to the tail back into Salisbury. The Stack oil warning light flashed on and I noticed the pressure had dropped to single figures at idle. After the near heart attack I gave it a gentle blip or two and it increased to the teens, it's idle norm is 29-30. As I crawled in the traffic I kept a careful eye and again it would drop at idle, mostly to around 12-15. I was minded to pull over but aside of the fact that there was no room to do so all other vital signs were normal and I kept telling myself that it was more likely a fault with the reading than the pressure. As I cleared the city and picked up a bit of dual carriageway the pressure came up to 50/55 at 3,000 rpm where I would have expected to see 75/80. At that point I was getting more concerned, pound notes were going through my mind and I was thinking towards finding a suitable stopping point. Whilst pondering the problem I switched off the heater fan, the day was starting to warm up, the moment I did so the pressure sprang up 20psi to it's norm of about 80 at 3,250 rpm. Thinking it was just a coincidence I clicked the fan on again and accordingly down went the pressure by 20. I repeated my on off, on/off experiment a few times since with the same result.
And so to the puzzle, why is my heater fan having the effect of reducing the oil pressure reading by 20? Fault with the Stack dash maybe, perhaps an earthing fault more generally or what? I thought maybe the it was due to a voltage reduction so I tried flicking the lights on and off a few times, this had no effect on the pressure reading but it did generate a wave from someone going the other way!
And yes before anyone says it, I know I should be not so much of a lightweight to have needed the heater on in the first place but in my defence it was a bit parky at 0730 this morning!
The solid state sensors uses a 5 volt regulated supply, so it is possible this has gone faulty and/or you have alternator/battery issue. But my first question would be if the sensor is fixed to the block, or on a remote? Vibration kills them and you may have noticed the first signs of failure.
Edited by DCL on Friday 30th September 15:06
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