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Discussion Starter · #1 ·
My Oil Pressure Guage has a mind of its own. The Truck runs fine so far. When driving, if I take my foot off the accelerator and coast to the point that the RPM's drop below 1,000, the guage basically dies and the needle drops to the bottom showing zero pressure. Then if I touch the accelerator it comes back to life and registers normal oil pressure until once again I find myself coasting (and below 1,000 rpm's) where it just dies. Again, the truck seems to be running fine and shows no signs of any issues yet.

I just wanted to find out if anyone has seen this before.
 

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One of the good things about these engines is, they will not run without adequate oil pressure. You have to have adequate low pressure oil (LPO) not only to lubricate the engine but also to keep the high pressure oil (HPO) reservoir full, so the high pressure oil pump (HPOP) can operate the injectors. If you don't have adequate LPO, you will, in short order not have HPO either and your engine will shut down.

With that said, bear in mind, the oil "gauge" on your dash is monitoring your LPO and is nothing more than an idiot light with a needle. So if that is the "gauge" you are referring to, it is receiving an electronic signal from a sending unit (the 6.0 bibles call it a switch and it is located near the oil filter). That sending unit may be failing on you or there may be a problem with the wiring, etc. You could look for a place to install a manual gauge to check your actual pressure. If you find that your actual oil pressure is falling to near zero (the needle is supposed to move to the "normal" range once you have 5-7psi), then you may have a bad low pressure oil pump (LPOP) or a bad oil pressure regulator. If you find the oil pressure isn't falling, then you get the fun of chasing down whether it's the sending unit or some other electrical gremlin.

Hope that helps!
 

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It is an oil pressure switch. Not a sender that gives a variable signal related to oil pressure.
You could have less than 8 psi the switch goes open and interrupts ground and the gauge drops but the engine can still run. The low pressure oil pump doesn't have to deliver much pressure in order to keep pumping enough to supply the high pressure oil pump for injection system. No oil pumping does stop the injection system and kill engine.

Check oil pressure with a gauge or if you inspect the switch and its leaking oil through connector then replace it. The ones that leak oil often go open at much higher pressure.
 

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Discussion Starter · #4 ·
Thanks for the replies gents. I'll take a closer look at her tomorrow. If it ends up being a LPOP that is going bad, what is that repair job like? I already did a delete, new OC, and a new HPOP (2005 Excursion but has the older style HPOP), so I am not scared to get dirty myself.
 

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Thanks for the replies gents. I'll take a closer look at her tomorrow. If it ends up being a LPOP that is going bad, what is that repair job like? I already did a delete, new OC, and a new HPOP (2005 Excursion but has the older style HPOP), so I am not scared to get dirty myself.
You have to take the front cover off the engine to get to the LPOP.
 

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It is an oil pressure switch. Not a sender that gives a variable signal related to oil pressure.
You could have less than 8 psi the switch goes open and interrupts ground and the gauge drops but the engine can still run. The low pressure oil pump doesn't have to deliver much pressure in order to keep pumping enough to supply the high pressure oil pump for injection system. No oil pumping does stop the injection system and kill engine.

Check oil pressure with a gauge or if you inspect the switch and its leaking oil through connector then replace it. The ones that leak oil often go open at much higher pressure.
You are correct, it is a switch. I called it a sending unit because it sends an electronic signal to the gauge once the pressure reaches 5-7psi. That is also why I called it an idiot light with a needle, since it really isn't telling you much of anything other than the switch is seeing 5-7psi . Probably a poor choice of words on my part. Here is the verbiage from the 03 6.0 bible:

The EOP (Engine Oil Pressure Switch) is a switch that closes a circuit to ground after engine oil pressure reaches approximately 5-7psi.
• This switch controls the oil pressure gauge on the instrument panel. When pressure is above 7psi the gauge will read normal and if the pressure drops below 6 psi the gauge will show 0.
• The information from the switch is not fed back to the PCM in any way and is to be used as a reference only.

The OP said it drops to zero when the rpms go below 1000. That implies the switch believes he has less than 6psi of oil pressure and would indicate a problem. That's why I suggested the manual gauge to verify whether his pressure is actually going to zero or near it. According to my Ford manual, the low minimum LPO is supposed to be 10psi. Since that switch is set up to read "normal" at 5-7psi,one can reasonably expect the engine to not run (and certainly not run right) at any pressure much below 6psi.
 

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Discussion Starter · #7 ·
Once again thanks for the detailed info guys. I am obviously hoping the problem is the OP switch and not the LPOP. It is hard to imagine that the problem really is the LPOP because it really runs fine, even when the needle reads zero. When I am at traffic lights and the rpm's are at 700-800, it reads zero. Like I said before, the second I touch the accelerator, it comes to life and reads normal. I suppose it could be an indication that the LPOP is on its way out. It is just weird that it fluctuates with rpm's.
 

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Let us know what you find.
 

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Well, actual oil pressure does drop some at idle once the oil is up to temp. But the "gauge" in your dash can't tell that unless it is dropping to below 6psi.. Otherwise, it will just read as "normal". Best bet is to get a real gauge on it and see what your real pressure is.
 

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Teamroper,
I wasn't trying to be snippy. I do have a huge problem with FORD lying for years. My cold reply was pointed at FORD. They call the fixed needle indicator a "gauge" and it is in no way, shape, or form a gauge by any industry accepted definition.
The competition has been able to sell trucks with honest oil pressure gauges and honest temp gauges for that matter.
 

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Didn't think you were. I agree it's a joke to call that thing a gauge, that's why I called it an idiot light with a needle. They could have made it a gauge by installing a sensor rather than a switch but they chose not to (most likely a bean counter decision).
 

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Has anyone figured out what caused the problem? I replaced batteries, sensors, and have the same exact problem explained above. Was it the HPOP? Any info would be awesome. Thanks
 

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Has anyone figured out what caused the problem? I replaced batteries, sensors, and have the same exact problem explained above. Was it the HPOP? Any info would be awesome. Thanks
The problem was the OP sensor. It had a crack in it and was not reading correctly. Do you have similar symptoms that I had? Engine runs fine but guage is erratic and drops to zero?
 

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By OP I assume you mean oil pressure sensor. I replaced that, I replaced batteries to eliminate electrical problem, I changed oil and filter to a motorcraft filter and 15-40 rotella. The truck will start when cold after a few cranks and run fine then the oil pressure gauge goes to 0. It runs fine so it obviously has oil pressure. And the oil pressure gauge goes up the second throttle pedal gets pushed. When you let go, a second later it drops.
 

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Discussion Starter · #16 ·
By OP I assume you mean oil pressure sensor. I replaced that, I replaced batteries to eliminate electrical problem, I changed oil and filter to a motorcraft filter and 15-40 rotella. The truck will start when cold after a few cranks and run fine then the oil pressure gauge goes to 0. It runs fine so it obviously has oil pressure. And the oil pressure gauge goes up the second throttle pedal gets pushed. When you let go, a second later it drops.
That is exactly what was happening to my vehicle and it was fixed with the new oil pressure sensor. The good news is that you know there really isn't a mechanical problem since the motor clearly wouldn't start or run without OP. I would double check the replacement OP sensor that you installed. It is easy to over tighten them and strip it allowing a little room for oil to leak out. I'm assuming you either installed a new O-ring with the sensor or at least inspected the old O-ring for cracks. I actually read where someone said that you can introduce a hairline fracture on the manifold in the thread cavity.
 

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Anything helps
I have a 2010 ford econoline with the 6.0 diesel in it. Started it up yesterday and it was fine for 10 min, then the oil pressure gauge went from the mid range to 0 when I stopped at a light. After that everytime the rmp would go under 900 the oil light(green) would come on and chime, the oil pressure gauge would go to 0. No noticeable change in the way it was running. Stopped to check it out and saw oil dripping underneath.
Not sure what the issue is. Any thoughts will be appreciated
 

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Discussion Starter · #18 ·
Anything helps
I have a 2010 ford econoline with the 6.0 diesel in it. Started it up yesterday and it was fine for 10 min, then the oil pressure gauge went from the mid range to 0 when I stopped at a light. After that everytime the rmp would go under 900 the oil light(green) would come on and chime, the oil pressure gauge would go to 0. No noticeable change in the way it was running. Stopped to check it out and saw oil dripping underneath.
Not sure what the issue is. Any thoughts will be appreciated
If the leak is minimal, it's likely a bad oil pressure sensor. It's an easy and cheap fix to replace it. Be very carefull not to over tighten the new one.
 

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Thank you for the response!
I really hope it is the sensor !
I am a complete fool when it comes to engine work,so can't express how much y'all s response helps. It may be the 6.4 I have had some trouble tracking down the engine that's in it.
 
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