its an interesting one, the factory has delays before it brings on warnings and also very low in pressure too, but u dont have the factory sensor hooked up ? also for sensors and oil i always avoid using thread tape, only use thread sealant if u have to, the tape can stop contact of the body to earth if it needs the contact it will cause issues or sometimes the tape if used and sensor removed it can curl up inside the thread and when sensor installed the first sign of pressure pushes the little bit of tape into the sensor and it blocks the hole causing issues also, aside from those and actual oil if its in the plug will disrupt the contact of the pins causing issues, but if they are all good its an odd one
After disconnecting the oil level/temp sensor, the same 'low oil pressure' warning condition exists, 'low oil pressure' warning chimes and holds steady at 29psi with the oil level/temp sensor disconnected, small red 'add oil' icon also still appears. So I assume the oil level/temp sensor is operating properly and has no effect in relation with the oil pressure sensor 'low oil pressure' warning. Note: Idle is set to 750rpm with an LS7 cam.
Current trouble shooting performed using fresh Amsoil 5w30 and a new WIX filter installed, oil level slightly overfilled, testing at 190F engine/oil operating temperature. When this issue first began I was running Amsoil 10w40. I felt it would be best to run a lower viscosity oil until I could determine the problem. When the engine was new, and for the first 4000 miles I was running Mobile1 5w30.
Engine has 7000 miles of aggressive driving. I have multiple Blackstone reports, and overkill amounts of inspection data and logs.
Previously I confirmed accurate electronic oil pressure sensor gauge readings using a mechanical oil pressure gauge at multiple rpms in comparison.
Blackstone trending reports reflect no excessive/atypical ppm bearing wear over time between scheduled 2000 mile oil changes. The current average engine compression drop is 18%psi cylinder compression compared to new at 172psi, cylinders within 5%-10% difference. Rebuilt heads at 6000 miles. No unusual tapping, knocking, or other sounds. Performance is excellent. I do note increased amounts of carbon in the oil between oil changes, no blue exhaust, and no excessive oil burning/low oil levels between oil changes. No signs of excessive blow-by, catch can volume is normal.
I'm assuming worn/looser bearing clearances exist at this time. In addition, worn piston rings and cylinders. No excessive cylinder wall discoloration or scoring exists. I recently began adding 0.5:100 parts Amsoil 2 stroke engine oil to the fuel aka 3.5oz per 18gl, (full tank).
I'm now leaning towards believing a failing/weakening oil pump pressure valve combined with worn/looser bearing clearances. The stock pump on an LSX376-B15 is a standard LS1/LS6 #6665, in comparison to the LSA #2289, (see attached). I realize the LSX is a priority main oil block (no squirters), compared to the LSA. However, I believe the LSX would benefit using the LSA pump with approx 30% more pressure/flow in comparison, I think the LSA pump would have been a better option with the OEM -B15 long block.
I believe it's possible the E67 ECU measures and interprets oil pressure rates (drop rates) over time based on a table at differing rpms. The ECM logic is a BLACK box to me, and I have no way of knowing for sure, maybe never!
In my particular situation, I only receive the 'low oil pressure warning 'chime' at 28psi-29psi hot idle, oil pressure never drops below 28psi at any time.
I've observed that if I hold a steady rpm and steady oil pressure on a highway, then lightly lift my foot of the pedal, there is a momentary 2psi oil pressure increase. Example: 43psi, let off gas slightly, pressure increases momentarily to 45psi, then decreases.
Thats all I have for now. Any feedback and/or suggestions are appreciated, particularly oil viscosity suggestions. 'Assuming' both worn bearings 'and' a weakening oil pump valve exists, would it be better to use a lighter or heavier oil? Also, what is the hot idle psi for a stock LSA (with oil squirters)?
At this point I'm going to deactivate the OEM oil pressure sensor and monitor the oil pressure via the Autometer gauge, the chime is driving me crazy now! I'll set the Autometer strobe to red and oil pressure audio alarm relay to 25psi.
For the amount of time and effort involved replacing an oil pump, I would rather just hold off and plan for an entire engine rebuild later down the road. I'll just keep driving and monitoring for now.