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Rather technical inquiry as to how the Gallardo ECU pulls the engine oil can up on the instrument cluster. It currently is coming on at idle, after the car is up to operating temperature.

Car is a 2007, motor was recently rebuilt.

Firstly, what are everyone's oil pressure readings with the 5.0?
I have heard the car is still within spec and this will definitely stir my curiosity as to what others are seeing as well. I have absolutely no recollection of what it use to run at but I am fairly certain it didn't run above 4 bar when cruising, which is where it still is.

Car is currently;
4 bar during cold start and warm up
2 bar when oil temp reaches 70 degrees
1-1.5 bar when car is at full temp of 90 at idle
2000 rpm makes 2 bar
3000 rpm makes 3 bar
4000 rpm makes 4 bar
5000 and up makes 5 bar
Car will never go above 5 bar even at 3 or 4K rpm when oil is below 90. It has the exact same readings with a 5w40 and 5w50 weight oils, changed filter in between as well.

Oil car seems to come on every time you hit a stop light, although it maintains pressure, however it does not come on at a consistent gauge reading. Sometimes it comes on when it dips below 2, sometimes it comes on when it sits at 1.5 for a minute or so, sometimes its on before the car has even settled into idle. I can't decide if its pressure related because of the inconsistency of when it pops on.

Secondly, does anyone know specific parameters to how the light is set off?
It seems the car only has the oil psi sensor located beside the oil filter.
I have tested the sensor at 1 - 6 bar pressure in .5 bar increments for extended periods of time with pressurized oil out of the car, and the gauge reads correctly. I do not believe the sensor is reading incorrect. It is rather sluggish to report the reading to the gauge but that's to be expected with the factory oil pressure sensors generally.
When the light comes on, if you press the CHECK button on the dash it simply states "turn off engine and check oil level," oil level is perfect.

I am confused about how it comes on mostly because when you change oil, procedure states to add 6QT, start engine at idle until oil light comes on, then add remaining 4QT to fill system. When the light comes on during the fill procedure the gauge does not drop off the 4 bar mark, which leads me to believe there should be a level indicator somewhere in the system.
Or it is somehow spec'd to be within a certain bar rating at certain RPM ranges within the ECU programming. Also, when I pressure tested the sending unit, above 2 bar the car immediately popped on the oil light (car was sitting with key on on position to read gauge) So it somehow knows there is no oil flowing in the system even though it sees pressure. Is there possibly a way to master restore the ECU programming? I am under the impression it still holds tons of data even if the battery isn't connected for long periods of time.

Also a possibility that somewhere along the lines the dealer that had the car who disassembled it dropped the pump causing internal damage. It does have an ever so slight leak from what appears to be the pressure regulator in the pump, basically just accumulated a small drip but wont actually hit the floor.

I'm hoping its not the pump but I have not yet ruled that out. If anyone understand the system very well it would be exceptional assistance in order to isolate what is causing the light to trip on.

Any other random suggestions or ideas anyone can come up with? I have had a couple people say that changing the battery is a good idea, that would amaze me if it fixed it but who knows! :eek::confused:
 

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I have no experience inside of this motor, however, I have been in others.

That being said, the oil pump will have a spring/valve assembly of some type that is used to regulate oil pressure as with viscosity changing the pump will have to work more/less and the same with engine RPM.

It would sound to me as if this was damaged or assembled incorrectly. You could remove the oil pressure sender and install an actual gauge to confirm that the reading is correct.

Also, you leak may be due to the fact that you have erratic high oil pressure. I would address sooner than later.

Mike
 
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