Pressure Transducer Sender Sensor with Connector, 1/8" NPT Thread Stainless Steel Fuel Pressure Sensor for Oil Fuel Air Water (5 PSI)

I used this with an Arduino. There's a bit of bounce in the readings, but it's reading reliably and working well.

I want to measure the pressure on my hydroponics pump which puts out about 3PSI. I ordered one and it worked fine, I ordered a second to expand my project. The second one did not work. They seem to be made well but given my experiance I would not recomend ordering this product. Documents: the pinout on the website inticates pins 1,2,3 but the connector is labled A, B , C.

I want this product to work, and it tries to, but… at no pressure it has a low reading, at low pressure it has a high reading, then the voltage drops as the pressure rises. So it’s really only useful for telling whether there is pressure in the system but not how much pressure. Strange.

I ordered two of these to track the fill level in a water tank, I ordered two specifically due to the mixed reliability on these sensors. The first one arrived in good condition and is currently working, the second one arrived with a damaged clip and lasted about 12 hours before displaying incorrect pressure information (pressure should have been 1.7 psi per my gauge and the other sensor, but was instead reporting 4.3-4.8psi). They're cheap, and I was able to dial in the accuracy very easily. Once I got everything set up with the arduino I had a good 12 hours of bliss where both sensors were within less than 2% of each other. I can't make any claim to exactly how accurate they are to the pressure gauge since its only graduated in 0.1 psi increments, but eyeballing it they were very close.

I connected the sensor up to power, and instead of putting out the expected 0.5V, it's putting out 4.27V, and it's only atmospheric pressure on the sensor. I looked inside of the orifice, and there was some kind of red liquid (see pictures). I left it lying upright overnight and thought that I might try to clean it out, and in the morning, the liquid was gone, but the sensor is still reading high. ***Edit: I was able to get the sensor reading more or less accurately, though I am still not sure what I did to get it working (I am still not sure what the red liquid was though). However, the readings are inconsistent, so I am looking into potential issues with my power source from buck converters as well as putting in noise filters for the power to the sensor and on the signal wire. If I can get it working better, I will update accordingly. This is the first time that I have been able to use this sensor. Unfortunately, I can't return the unit through Amazon. I bought it a few months ago, but my project has proven to be a lot more complicated than expected and I am past the 30-day window. (I'm trying to read this sensor on an Arduino and power it off a 5V power supply, but I tested the output with a multimeter.)