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High Oil Pressure

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Old 08-06-2019 | 05:34 PM
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Angry High Oil Pressure

Hi folks,

Here's the current situation. Oil light on instrument cluster is ON, and Oil Pressure Gauge is at MAX (~5).

Most relevant information (maybe):
Engine has been replaced. (Long sad story.) Runs fine.
Pressure has been tested at the switch location with an independent tested.
Oil filter has been changed twice.
Oil has been changed.
Oil level is at high end of the second notch.

Other things we tried before the real pressure tester:
Pressure gauge switch was broken as it turns out, and has been replaced. Still at MAX.
Oil light is on regardless of gauge even being plugged in.
There doesn't seem to be a short anywhere.

Dash lights and instrument work has happened - I replaced the dash.
Old 08-06-2019 | 07:15 PM
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Could it be the low-oil light? That's a different sensor from the pressure
Old 08-06-2019 | 07:18 PM
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If you have a 2 pin pressure sensor, swap the two wires and see how it performs.
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Old 08-06-2019 | 08:00 PM
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Originally Posted by SeanR
If you have a 2 pin pressure sensor, swap the two wires and see how it performs.
Could do that - but the issue remains that with an external pressure sensor, they're reading a 6+, so the current sensor isn't specifically an issue (I guess). It's just what got me alerted to this pressure issue.

Also - the amateur electrician in me worries about flipping polarity and frying things. That's not gonna happen here?
Old 08-06-2019 | 08:01 PM
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Could it be the low-oil light? That's a different sensor from the pressure
Ah, that's an interesting point. Still worried about the high pressure situation on the other side of _whatever_it_is_ but that's an interesting point.
Old 08-06-2019 | 08:51 PM
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Originally Posted by Dan Martinic
Could it be the low-oil light? That's a different sensor from the pressure
Ah. It seems that only newer 944s had that, and the light that's on is also "Oil Pressure Warning Light" (as seen here: http://www.uriarte.dk/porsche944/garage/owners83.html ).

So back to the original question then - what could raise the pressure like this? Engine sounds fine...
Old 08-06-2019 | 09:10 PM
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Oooooh, I found this on the intarwebz: http://944foot2thefloor.blogspot.com...-oprv-oil.html

That looks like juicy reading.
Old 08-06-2019 | 10:30 PM
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Let me know when you get it sorted out, my car does the same thing
Old 08-06-2019 | 11:12 PM
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Originally Posted by Beige944
Let me know when you get it sorted out, my car does the same thing
how long have you been running like this? Asking for a friend.
Old 08-06-2019 | 11:15 PM
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Originally Posted by bugzilla
Could do that - but the issue remains that with an external pressure sensor, they're reading a 6+, so the current sensor isn't specifically an issue (I guess). It's just what got me alerted to this pressure issue.

Also - the amateur electrician in me worries about flipping polarity and frying things. That's not gonna happen here?
You don't need to worry about that in this case. one wire is for the warning light and the other is for the gauge. When the wires are swapped you will get the gauge pegging to max with the key on, engine off. And when you start it you will have a pegged gauge and a light on.
Old 08-06-2019 | 11:49 PM
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It's common for oil pressure to read 5 bar (possibly slightly higher) after start up on a cold engine.
What's your oil pressure after it has warmed up? Should drop down to around 2+ bar at idle and normal operating temp.
What weight oil are you using?
Old 08-07-2019 | 12:06 AM
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Originally Posted by bugzilla
how long have you been running like this? Asking for a friend.
Been like this about a month or two. It started around the time that I changed the oil pressure sender and had the gauge cluster out, so I suspect it's an electrical issue.
Old 08-07-2019 | 12:18 AM
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Originally Posted by Beige944
Been like this about a month or two. It started around the time that I changed the oil pressure sender and had the gauge cluster out, so I suspect it's an electrical issue.
Oh ok. Not the same thing then.
Old 08-07-2019 | 12:19 AM
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Originally Posted by mj951
It's common for oil pressure to read 5 bar (possibly slightly higher) after start up on a cold engine.
What's your oil pressure after it has warmed up? Should drop down to around 2+ bar at idle and normal operating temp.
What weight oil are you using?
I drove 20 min and it stayed pegged at MAX. Using 0W-40 synthetic in there now.
Old 08-07-2019 | 12:51 PM
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I think you are on the right track. OPRV controls oil pressure, so when having pressure issues it is the first thing that dhould be checked.


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