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My name is Dale.
There is a oil pressure sensor that is used on many vehicles that reads the oil pressure before it will allow the computer to send spark to the engine. Many times the sensor is not bad but there becomes high resistance at the plug terminals where the harness plugs into the sensor and creates an intermittent open circuit. It is possible that the sensor itself is bad but when the sensor opens or an open is created by corroded electrical connectors the engine will shut down.
I would check that circuit extremely carefully. I will see if I can find a wiring schematic for you to help you trace the harness out and find the sensor and the electrical plug that hooks to it.
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PLEASE NOTE: It is also possible that the problem is fuel related. If you can get the engine in a no run/no start condition, give it a shot of Berryman's B-12 SPRAY Carburetor Cleaner right down the intake/throttle body and see if it responds. You can pick up a can of this product at any auto parts store. Consider the B-12 as portable fuel in a can.
This is just another test procedure to help isolate the problem.
In addition here is a link to the sensors and controls involved with your engine:
Click LINKS Below to Enlarge:
As a final note, you should hook up a OBD II scanner to the vehicle and see if there are any soft or hard codes that are displayed. Many times this will lead to the problem. The order of the codes is reallyimportant. Usually the first trouble code displayed was the PRIMARY failure.
Well, Thank you for the detailed response. I have no idea how many miles are on this engine but what you are describing is LOW oil pressusre due to a internal mechanical problem that is causing the oil pressure to drop. The oil Sender Unit is different from the oil pressure safety sensor. These days there are usually two sensors that relate to the oil pressure. One for the guage (which you have replaced) and one to imobilize the engine if the oil pressure gets to low.
You need to put a master oil pressure gauge (you can hook it up where your oil pressor guage sender is) and record the oil pressor cold at idle, cold at 2,000 RPM's then engine Hot at idle and Hot at 2,000 RPM's. What you are doing when you speed the engine up (HOT) to keep it running is keeping the oil pressure high enough to meet the the threshold of the oil pressor safety sensor (imobilizer) so it will not shut the engine down.
So, the story looks like there was probably some addition damage either in the main, cam or rod bearings when the engine was overheated. I know you do not want to hear this but my job is to tell you the truth so you know where to look and what to do. So the next step is the Hot & Cold Master oil pressure test.
Well you have found the problem. 10 psi at any RPM is to low. Depending on how hot the engine got more than likely the oil got so hot it could not lubricate the bearings. When this happens it not only destroys the bearing but also the shafts. Unfortunetly you will either have to put a new short block or a complete engine in the vehicle. You daughter is not the first person to completely cook an engine.