Oil pressure light on.. gauge ok
08-30-2017, 11:20 PM
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Oil pressure light on.. gauge ok
Just picked up my first Porsche.. 1987 944s, Diamond blue metallic, black interior, manhole cover wheels, 220,000kms.
Cosmetically pretty good. Drives nice but not without some issues... the first one: After driving it for 10-15 miles after picking it up the oil pressure light came on (at bottom of gauge as well as the main warning light "!"). The pressure gauge itself was fine.. around 2 bar at idle, 4-4.5 under at higher revs.
The warning lights would come on initially at idle after engine warms up for 3-5 mins.. Once the engine is hot the lights come on anytime I'm not on the throttle. Occasionally I can even see it flicker faintly cruising at 3000rpm. Also, when it is on it is never as bright as when the parking brake is on.. always dimmer and flickering. I changed the oil with 20w50 Castro dino.. no change.
After a bit of research I figured it was probably the sensor.. (output to warning light acting up). Finally got around to changing it today with FAE from Pelican and it's exactly the same.. no change.
I can't believe both gauges have the same fault so I'm assuming (hoping?) it's a wiring issue now but not sure where to start the search.
Any help much appreciated!
Cosmetically pretty good. Drives nice but not without some issues... the first one: After driving it for 10-15 miles after picking it up the oil pressure light came on (at bottom of gauge as well as the main warning light "!"). The pressure gauge itself was fine.. around 2 bar at idle, 4-4.5 under at higher revs.
The warning lights would come on initially at idle after engine warms up for 3-5 mins.. Once the engine is hot the lights come on anytime I'm not on the throttle. Occasionally I can even see it flicker faintly cruising at 3000rpm. Also, when it is on it is never as bright as when the parking brake is on.. always dimmer and flickering. I changed the oil with 20w50 Castro dino.. no change.
After a bit of research I figured it was probably the sensor.. (output to warning light acting up). Finally got around to changing it today with FAE from Pelican and it's exactly the same.. no change.
I can't believe both gauges have the same fault so I'm assuming (hoping?) it's a wiring issue now but not sure where to start the search.
Any help much appreciated!
08-31-2017, 02:12 AM
#2
What brand of oil filter did you use? clarks garage is a great reference to test the gauge and the warning light. if that tests ok then I would be looking at the oil pressure relief valve.
08-31-2017, 10:26 AM
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Ok thanks jeffro.. I used a Bosch filter. I'll check the sender as per Clarks..
The only problem is he has no procedure to check the output for the light. His write up shows that one output from the sender is for the gauge (ie:needle) and the other is for the warning light (or "alarm", as he refers to it). I'm assuming the gauge output is correct and that the engine has good oil pressure. Hopefully I can confirm this by testing the sender but doesn't help explain the light coming on.
Hopefully I'll find some time today play with it.
The only problem is he has no procedure to check the output for the light. His write up shows that one output from the sender is for the gauge (ie:needle) and the other is for the warning light (or "alarm", as he refers to it). I'm assuming the gauge output is correct and that the engine has good oil pressure. Hopefully I can confirm this by testing the sender but doesn't help explain the light coming on.
Hopefully I'll find some time today play with it.
08-31-2017, 03:57 PM
#4
Burning Brakes
There are two wires at the oil pressure sender; one for the gauge and the other for low oil pressure warning light.
Start by disconnecting one of the two and see what changes. If the gauge still works then you will have disconnected the warning light wire. If the wire is disconnected and the lamp still flashes then you have a wire problem between the sender and the instrument panel. If the warning light stays out then it's a sender problem.
Test it and let us know what you find.
Start by disconnecting one of the two and see what changes. If the gauge still works then you will have disconnected the warning light wire. If the wire is disconnected and the lamp still flashes then you have a wire problem between the sender and the instrument panel. If the warning light stays out then it's a sender problem.
Test it and let us know what you find.
08-31-2017, 07:41 PM
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Good advice Paul... Thanks.
Good news, (for the engine at least) the light stays on even when wires are disconnected, so my problem is wiring. At least now I can drive it with confidence that oil pressure is ok. I'll do some research on the wiring system and I'm sure I'll have more questions soon.
Good news, (for the engine at least) the light stays on even when wires are disconnected, so my problem is wiring. At least now I can drive it with confidence that oil pressure is ok. I'll do some research on the wiring system and I'm sure I'll have more questions soon.
