Oil pressure sensor/switch. http://www.powerstroke.org/forum/6-0-motor-problems/1082050-oil-pressure-trouble.html

 

What year model?

 

Sorry 2003 f250. Is it true that if the oil pressure does drop like that the truck wont run.

 

It IS true that with no LPOP pressure, the truck won't run. The kink in the works is that the LPOP pressure gauge is not telling you exactly what the LPOP pressure is - even when it works.

Here is the deal:

The LPOP oil pressure sensor is a switch that activates at about 7psi. The signal goes straight to the dash cluster with NO processing by the PCM. On the 6.0, the engine diagnostics have no idea of the LPOP system pressure.

But... the LPOP system feeds the HPOP system and a HEUI injection system will not run without HPOP pressure. So... the idea is no LPOP-no HPOP. That is true. There is a gray area with low LPOP pressure, though.

This came up in a recent thread:

http://www.powerstroke.org/forum/6-...erformance-parts-discussion/1108778-way-check-lpop-pressure-bpd-oil-cooler.html

Andrew from BPD said this in response to a question of mine about LPOP pressure:

...The gauge moving up to the "normal" range, to me, means that there "should" be ample low pressure oil to feed the pump and build adequate ICP pressure to start. We have seen as low as 2-3psi on the low side and still build adequate ICP pressure to start. ...

This means that it is possible - emphasizing POSSIBLE - that a weak LPOP system could be maintaining low positive pressure - 3-6psi - that would allow the engine to start but would not be sufficient to cause the dash gauge (trigger threshold=7psi) to raise. This is not a likely condition, though.

If I were you, I would:

1) Disconnect the oil pressure switch and jumper the center pin to batt ground. It should cause the dash gauge to come up. If so, your pigtail-to-cluster is fine. If not, look there.

2) If the pigtail-to-cluster is fine, replace the sensor/switch. They are cheap and it will take you like 3 minutes. If not, you have to figure out if it is the pigtail, wire chafing (see link), or the connection at the cluster.

http://www.powerstroke.org/forum/6-0-motor-problems/1096562-6-0-harness-chafing.html

3) If it still is not cooperating, I would throw a pressure gauge on your LPOP (port at front center of oil cooler plate or in the cap or...) and see what your pressure actually is.

All of that said, I'm thinking that your connector is loose.

 

This didn't start until yesterday when I replaced the thermostat, did the coolant filter kit and the blue spring mod. So I had the turbo intake pipe off and may have hit something or disturbed something. I will go take a look now.

 

Every 03-04 I've seen with low oil pressure at idle was missing the steel ball from the hpop. When it falls out low pressure oil just spills out the side of the hpop feed passage. If the ball has fallen out and you keep running it the hpop won't last long. You can tap and plug the hole in the hpop.

 

Last night I bumped my idle from 600 to 825 with the sct and it hasn't dropped today yet.

 

Hey guess what my stupid oil gauge is doing it again! So the truck just sat for two months, i needed new batteries. So today i put new batteries in and it fired right up. I took it for a spin and now when i come to a stop or put the truck in park anything under 740 rpm the oil gauge drops to zero. I did drop the idle in June to 700 rpm but had no problem the rest of summer. I did have the air box off a few times maybe i hit something i don't know. The truck runs fine. I need to get a mechanical gauge on it.

 

i would just try a switch

http://www.powerstroke.org/forum/6-0-motor-problems/1082050-oil-pressure-trouble.html

 

Alright so right after i wrote this last reply i went out and wiggled a plug that is under the air intake tube next to the fuel bowl by the lines. I took it for a ride up to my parents house and the gauge didn't drop. So far my best guess is a bad connection or a chafing. I will update in a few days and let you guys know if it comes back or stays good.

 

Disconnect it and check for oil in the connector. If there's oil, replace the sensor.
A lot of times a leaking switch will cause the open circuit at idle

 

Will do. But it will have to wait a few days tomorrow the high temp here will be 20 degrees.

 

I am having the same problem after the radiator and water pump were changed out. Low oil gauge pressure until the RPM's go over 800 rpm.