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Search is pulling up too much irrelevant threads so time to ask...
What's my best option for an OPSU?
I just had it replaced with an ACD, but I about **** myself when the gauge dropped to zero and the dash light came on. The car runs great, but when I've been driving for a while and if I'm at a light, sometimes it will bottom out on zero, then go back to normal with throttle.
Is there anything I need to do, when installing the OPSU? Maybe I installed it incorrectly? I read in another thread about some screen or something, that might need to be cleaned... I might be remembering the details wrong.
Is there more than one OEM or updated P/N? I bought the 19244505 from Summit. Maybe it's the wrong unit?
Oil pressure sender is a variable resistor to ground and is hardwired to the gauge (doesn't go through any ECM). Gauge reads high oil pressure when the sender has a lot of resistance to ground, and reads low oil pressure when the sender has low resistance to ground.
If the wire connection were loose then I think the gauge would peg to high pressure side. I'm not sure if there is a fault in the wiring that could cause it to peg to the low pressure side other than a sender short to ground. I'd take the low oil pressure reading very seriously until you can troubleshoot the cause.
I tend to buy the real Delphi sensors when it comes to things like oil pressure and coolant senders. I've had cheaper stuff literally fall apart into pieces on engine.
Oil pressure sender is a variable resistor to ground and is hardwired to the gauge (doesn't go through any ECM). Gauge reads high oil pressure when the sender has a lot of resistance to ground, and reads low oil pressure when the sender has low resistance to ground.
If the wire connection were loose then I think the gauge would peg to high pressure side. I'm not sure if there is a fault in the wiring that could cause it to peg to the low pressure side other than a sender short to ground. I'd take the low oil pressure reading very seriously until you can troubleshoot the cause.
I tend to buy the real Delphi sensors when it comes to things like oil pressure and coolant senders. I've had cheaper stuff literally fall apart into pieces on engine.
I never had an issue prior to the swap of the OPSU; I just swapped it out for a new unit because I was freshening up all the external stuff on the engine.
What's the P/N for the Delphi? I've only found one for the ACD unit.
Rock Auto has the AC Delco D1818A which they are claiming has been validated to the same standards as the OE part. At least it's sort of in the GM family. Maybe you can turn yours back in on warranty?
They give some cross-references to GM part numbers but you'd have to run the trap line to figure out what is the difference and whether those even exist any more. Just a couple weeks ago I was able to buy the Dephi from Rock Auto for my 3rd gen so they're still out there, just need to find them. And maybe I'm just being played by branding and both Delphi and AC Delco are the same part.... ?
Had a similar issue and it turned out to be a poor plug connection to the sender. I still like the factory OPSU due to it working with the factory gauge cluster but rather than question the gauge both of my engines are set up to connect a mechanical gauge. Not an expensive mod and most of all it gives you peace of mind. ICT Billet makes one to replace the oil cooler block off plate on the oil pan or you can just mod the existing one. You can see it here in this picture connected to the braided line. When in doubt go with a mechanical gauge.
Had a similar issue and it turned out to be a poor plug connection to the sender. I still like the factory OPSU due to it working with the factory gauge cluster but rather than question the gauge both of my engines are set up to connect a mechanical gauge. Not an expensive mod and most of all it gives you peace of mind. ICT Billet makes one to replace the oil cooler block off plate on the oil pan or you can just mod the existing one.
You can see it here in this picture connected to the braided line.
When in doubt go with a mechanical gauge.
Nice, I was considering this. Where did you mount the gauge?
There are high accuracy pressure sensors but it's probably pointless unless you have an ECU where you can dial in a custom transform function. Being able to datalog pressure is the next level above watching a gauge with your eye. I don't know if the 0411 ECM can do that?
I have Holley EFI and use a 3-wire sensor to send a data stream into the ECU for data logging, and the dash gauge has to run off a different resistor style sensor. I actually just bought a different sensor that is scaled better for my gauge. You can put any sensor on your engine, just gotta do the research to know what will work best with your gauge calibration.
There are high accuracy pressure sensors but it's probably pointless unless you have an ECU where you can dial in a custom transform function. Being able to datalog pressure is the next level above watching a gauge with your eye. I don't know if the 0411 ECM can do that?
I have Holley EFI and use a 3-wire sensor to send a data stream into the ECU for data logging, and the dash gauge has to run off a different resistor style sensor. I actually just bought a different sensor that is scaled better for my gauge. You can put any sensor on your engine, just gotta do the research to know what will work best with your gauge calibration.
How do you do that at $65 a pop, lol? It's just a stock 02 T/A with headers. I just want to find the best one with little to no quality issues.
You don't have to guess, you do some testing to characterize you gauge and then look at manufacturer technical specs to find a pressure sender that's a good match. It's 95% effort, 5% money. Totally doable --- but it's not for everybody, I realize that. Just brainstorming how you can make the gauge useful. But there's no point until you troubleshoot the problem and you'll need the mechanical gauge for that job anyway.
You don't have to guess, you do some testing to characterize you gauge and then look at manufacturer technical specs to find a pressure sender that's a good match. It's 95% effort, 5% money. Totally doable --- but it's not for everybody, I realize that. Just brainstorming how you can make the gauge useful. But there's no point until you troubleshoot the problem and you'll need the mechanical gauge for that job anyway.
Yeah, I don't know how to analyze anything like that. I just typically buy the OEM unit and run with it, unless there's a better known A/M part available.
I'm planning on running both, but if the mechanical reflects an actual issue, I guess I delve deeper.
03-26-2022, 10:55 PM
Best option for Oil Pressure Sending Unit 
