'90 LX 5.0L Oil Pressure Problems

The oil pressure gauge seems to be pretty erratic, sometimes showing zero pressure other times showing middle of the normal range at the same engine RPM. This past Monday morning I started the car after it had been sitting for three days and the engine knocked (like it normally does immediately after I change the oil until it build up to normal presure-usually like two seconds or so). This time it kept knocking for about five seconds or so and I shut it down and checked the oil-it almost didn't register on the dipstick, but the oil level trouble light never came on.

I added a little over a quart of oil and the knock quit, but the oil pressure gauge is still erratic.

When the oil pressure sensor malfunctions what are the usual symptoms? Where is this sensor located? How can I measure the oil pressure to check the oil pressure gauge?

Thanks.

Lack of oil is always bad, do you have a leak or is your car burning oil through the motor?

I would try one of two things leaning more towards my second option.

One, replace the oil pressure sending unit. Located on the drivers side of the motor towards the front. I will try and supply a picture after.

Two, get an aftermarket gauge and hook it up and test for oil pressure. Stock gauges are known for not being accurate.

Agree.
For the gauge fluctuations, you've got the classic symptom of a bad sender. Change it.

I replaced the oil pressure sensor and now I have a very steady mid-range reading on the gauge. It took maybe ten minutes once I got the front end up on the ramps; the sensor was fairly easy to reach with a wrench from below.

Thanks for the help!:smile:

I replaced the oil pressure sensor and now I have a very steady mid-range reading on the gauge. It took maybe ten minutes once I got the front end up on the ramps; the sensor was fairly easy to reach with a wrench from below.

Thanks for the help!:smile:
Sorry I never got that pic posted. Glad you were able to get it taken care of though.