03 5.4L 2V - new oil pump won't prime

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craig72

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I am getting ready to change my oil pump on my 4.6 Romeo as part of a timing job. I saw the same video you mentioned above and even have it bookmarked. I'm interested to know what you find out.
 

Vincent Vega

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@Eric M This is just a thought but the oil sending wires may have gotten a beating as you were removing the LH valve cover, and then removing and installing the power steering pump. Oil pressure sending wires go right through there. Oil in the filter and no top end clattering while it was running suggest you might have oil pressure. I recall being worried about how many times I pulled and poked those wires while I was doing my timing, so just something to consider. Will be figured out or confirmed when you test using an external gauge that @Hamfisted suggested.
 
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Eric M

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@Eric M This is just a thought but the oil sending wires may have gotten a beating as you were removing the LH valve cover, and then removing and installing the power steering pump. Oil pressure sending wires go right through there. Oil in the filter and no top end clattering while it was running suggest you might have oil pressure. I recall being worried about how many times I pulled and poked those wires while I was doing my timing, so just something to consider. Will be figured out or confirmed when you test using an external gauge that @Hamfisted suggested.
You are right about the wires. I did come into contact with them many times during the rebuild. I will need to inspect them more closely and check for voltage.
 
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Eric M

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I am in the process of checking the oil pressure sensor wires and the sensor itself. I have a couple of questions:

1. The sensor has one blade that inserts into the plug. How can I test to see if current is reaching the sensor if there is only one slot in the plug? I tried putting one lead from a multimeter into the plug slot and the other lead to ground, but that did not work. I also tried using a test light, but same result. Perhaps I need to crank the motor while testing (?).

2. I bench tested the sensor for continuity. The sensor is in the open position. Is this correct? Some sensors start in the closed position and then open up when the motor is running. So, the question is whether the sensor for this particular vehicle needs to be in the open or closed position when at rest. This will tell me if this sensor is bad or not.

I'll keep Googling this ....

Thanks for any assistance you can offer.
 

Hamfisted

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With the key in the RUN position and you ground the harness plug, do you get a normal oil pressure indication on the gauge ? The sender should close circuit between 5 -10 psi of oil pressure. Cheap enough just to replace the sender.

Single Pin Oil Pressure Switch Test Video






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Eric M

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Thanks for the diagram. I will resume testing when my new sender arrives tomorrow.
 

SafariGoneWrong

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I couldn’t get pressure by cranking the engine after installing a high volume Melling pump during a full timing job along with roller followers and lash adjusters. I took the chance of starting the engine and got pressure within about 5 seconds. Risky business but no ill effects 20K miles later.
 
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Eric M

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I couldn’t get pressure by cranking the engine after installing a high volume Melling pump during a full timing job along with roller followers and lash adjusters. I took the chance of starting the engine and got pressure within about 5 seconds. Risky business but no ill effects 20K miles later.
Good to know. I may be going this route myself if the manual priming doesn't work out.
 
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Eric M

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Things just keep getting weirder.
I used this oil pressure test kit (thanks toHamfisted for the recommendation) and it worked great, I think. I used this kit to prime the pump. It comes with everything you need for a DIY pump primer except the pump itself. Just remove the gauge, insert the appropriate fitting in its place, and connect whatever pump you have on hand. I used a pump similar to this one. One hose in the oil jug, the other hose connected to the fitting on the gauge hose, whose opposite end is inserted int the oil pressure sensor orifice.

After the priming, and with the manual gauge once again hooked up, I cranked the motor and the gauge got up to the 20 psi range. So, I figured everything was A-OK. I ran the motor and the pressure rose to 90 psi and stayed there.

So, I figured I was basically done with this project from hell. Wrong again. I put in the *new* oil pressure sensor and connected the wire. Started the motor, which sounds great. After ten minutes of idling, the "hi temp low oil" light comes on. There is plenty of oil in the motor. Also the "Low oil Pressure" light has never turned off and the oil pressure gauge has not moved.

So, it appears that my oil pressure is quite high, but there is clearly some issue. Is it possible that I lost the prime during the time in which I unhooked the gauge and installed the new pressure sensor? Seems unlikely.

Is the high volume oil pump causing the sensors to malfunction, and in reality everything is fine?

This car can truly drive a man to drink....
 

Hamfisted

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Can you take a jumper wire and ground the sender's plug then turn the key on and see if the oil pressure gauge goes to the middle and the oil pressure light goes out? This will at least test the circuit and the instrument cluster gauge. If you look into the oil fill cap opening into the motor do you see oil on the parts? Or do they still look dry? What brand and part number pressure sender did you use ? That "High Temp Low Oil" references oil pressure, not oil quantity. So it's all oil pressure related on your issue.




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