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I was hoping the threaded hole near the front of the block with the sensor and red&white wires in the picture would be suitable for a 2nd oil pressure sensor, but it doesn't seem to read anything. Is this just an oil return area?
(FYI - My rear block oil pressure sensor connects to a gauge; I want a second connected to my ECU. Yes, I know about the oil cooler bypass, but it is too close to my headers for a sensor there.)
It’s directly into the main oil passage off of the oil pump. You definitely have pressure there. I’ve circled the port here on a sleeved 5.3 block I recently sold. All LS blocks are the same in this regard.
It’s directly into the main oil passage off of the oil pump. You definitely have pressure there. I’ve circled the port here on a sleeved 5.3 block I recently sold. All LS blocks are the same in this regard.
Thank you! That is what I thought, but my Holley Dominator does not read any oil pressure from that sensor. Hard to see in my picture, but it is a 3-wire sensor. I can now concentrate on diagnosing it as an electrical or sensor problem.
It’s directly into the main oil passage off of the oil pump. You definitely have pressure there. I’ve circled the port here on a sleeved 5.3 block I recently sold. All LS blocks are the same in this regard.
+
Like Che70velle says...
I use that hole to pressure prelube all my LS's...
4.8 Oil Pressure (Oil) An oil pressure input is a standard feature on Holley EFI. A connector is installed that is plug-and-play with Holley 100 PSI pressure transducer PN 554-102. A different 0-5V transducer can be used, but the calibration must be set up as a custom sensor in the software. If these are not connected to a pressure transducer, the Fuel and Oil Pressure will read “LOW Err” in the data monitor. This will not cause any issues. A18 – Sensor Ground (Pin A) A26 – Sensor +5V Reference Out (Pin B) A20 – Fuel Pressure Signal (Pin C
4.8 Oil Pressure (Oil) An oil pressure input is a standard feature on Holley EFI. A connector is installed that is plug-and-play with Holley 100 PSI pressure transducer PN 554-102. A different 0-5V transducer can be used, but the calibration must be set up as a custom sensor in the software. If these are not connected to a pressure transducer, the Fuel and Oil Pressure will read “LOW Err” in the data monitor. This will not cause any issues. A18 – Sensor Ground (Pin A) A26 – Sensor +5V Reference Out (Pin B) A20 – Fuel Pressure Signal (Pin C
Yup, pretty sure I have that Holley oil pressure sensor; but have never had a reading from it. I have the Holley fuel pressure sensor and that reads correctly.
For anyone stumbling on this thread in the future, the Holley EFI Pin A26 (Sensor +5) and A18 (Sensor Ground) also connect to the MAP and TPS; in total its Oil Pressure, Fuel Pressure, TPS and MAP.
If any of those sensors or the wires to them short out (ask me how I know), none of those sensors will read correctly; e.g. the MAP will read 15kpa. Interestingly the CTS and IAT will read 300F, causing the fans to turn on. Obviously the engine does not start.
I will add that the pressurized oil readings from there will read a few lbs higher than from the port where the OEM sender is located. Because this is pre-oil filter......
I use that port to pressure prime oil throughout a new motor, leaving valve covers off to see oil getting to every rocker. It can take 20 mins or so, rotating the crankshaft 90* every 5 min, 4 plus qts of oil and 60 psi of pressure in the oil tank. iCT and Autometer make nice 16mm to 1/8”pipe adaptors to screw into that port.
Yup, pretty sure I have that Holley oil pressure sensor; but have never had a reading from it. I have the Holley fuel pressure sensor and that reads correctly.
For anyone stumbling on this thread in the future, the Holley EFI Pin A26 (Sensor +5) and A18 (Sensor Ground) also connect to the MAP and TPS; in total its Oil Pressure, Fuel Pressure, TPS and MAP.
If any of those sensors or the wires to them short out (ask me how I know), none of those sensors will read correctly; e.g. the MAP will read 15kpa. Interestingly the CTS and IAT will read 300F, causing the fans to turn on. Obviously the engine does not start.
Shorting out the 5v reference is bad news. I am glad you got that sorted out.
Forgive my noob question, but couldn't you split the signal coming from the oil pressure sensor instead of using two sensors? I only ask because I'm going to be running into this same issue soon.
02-29-2024, 08:23 PM
What is this threaded hole in an LS3 block 
