2 days ago I drove my 03 f250 10miles non stop at 60mph and when i got to a intersection and the engine went to idle the oil pressure gauge went to 0. I checked the oil and it was low. so i left it on the side of the road and got a ride to get oil. It only took 3qts to fill it up. There was probably a hr be for i put the oil in it. Then it was fine no problem the rest of the night driving 20 miles. well today it did it again in the same intersection. I stopped, the gauge went to 0 as soon as it was at idle. I checked the oil but it was full. I was on my way to work this time so i kept going. the engine ran normal and i kept it above idle. On my way home it ran just fine. the gauge read normal the whole time. Ill put a oil gauge on it as soon as i can get 1. the part stores do not carry them around here. I was wondering if the sending unit or gauge mite be a common problem on these trucks. The gauge dose not flutter with rpm. it drops from the middle to 0 then back to the middle as soon as i touch the throttle.

 

It could be the oil pressure sending unit, but be aware that the oil pressure sending unit is really a switch. It activates at 5 psig when normal pressure at 700 rpm (apprx idle speed) is 12 psig.

If the pressure is really low, it can be hard to start due to low preassure in the "high pressure oil system". The low pressure pump feeds the high pressure pump and you need at least 500 psig from the high pressure pump to start.

A true low or no pressure issue could be caused by the oil pressure regulator, gerotor oil pump or an internal lube oil pressure leak.

The oil pressure switch has a one pin connector that frequently needs to be replaced. The switch at the dealer is about $55 and the connector is about $28. 15/16 crows foot to remove.

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ok well it starts fine and runs fine so im thinkin its the gauge.

 

I vote for sending unit. Correct my thinking if I'm wrong but; If you lose low press. oil then you starve the high press. pump and that will kill the engine due to no high press. oil to fire the injectors. Sort of protects itself wether intended to work that way or by accident.

 

time for a correction in your thinking. sorry

If you have a high pressure leak that is large enugh it will drop base oil pressure. how every it may still run fine but will go long crank or hard start when warm but not always true.Most people overlook the fact that they are directly tied together.
varify base oil pressure with the engine running with a gauge to do so remove the sending unit and tie in there.

First remove the oil filter and hold down the bypass valve with a screwdriver while someone cranks the engine over. remove the ficm relay so the truck will not start or you can also crank the engine over with the key in the off position by juming the starter wire thats next to the right battery to B+. if the filter housing fills up you problem is most likly on the high side and not the low side.

Now for what the issue is and what to do about it.
The issue that is most common is the ball poping out of the high pressure oil pump. A new pump is about $800 + labor this will run you about 2k-2400 total.

Now for the good part...
I can tell you the pump is good because your truck runs and goes down the road just fine. so let me save you the cost of the pump. when you find out if I am right remove the pump and tap the hole were the check ball was and incert a pipe plug were the ball was and reassembel and drive it down the road. Also there shold be no need to replace the ipr durring the repair unless the screen is damaged, sucked in or the screen has come off the ipr valve.
so if you do all this yourself you will safe about $2350 dollars. nice huh?

o ya and the rock on dude is cool

 

tap the clear plastic with your hand itll come backup

 

i tried that but i ran over a honda i think. I dont know. I felt a bump and looked back. But I was not paying attention to the road so i dont know if it was already flatend or not.
I bet its just the sending unit. hopefully ill find a gauge tomorrow.

 

ya let me know how that works out would ya.

 

well i didnt get to my truck today. i took some cheap sleeping pills so i could get up early to work on it. but they didnt work and i felt like ***** all day.
im sure its just the sending unit. The oil is full, it only dose it when its warm, It dosent do it all the time when its warm, and it gos up and down like a light.

 

been 4 days now was wondering if you have reached a conclusion to the issue?

 

if the ball popped out of the hpop, it will drain the hpop supply galley causing extreme crank time. I vote for the sending unit being bad..hopefully

 

Chezit,please explain again how you get HPO without any LPO.

 

it sounds odd but its very true. If the leak on the hpp side is large enugh you will drop the pressure on the low side. lowside is still pumping oil but the high side will consume it faster then the low side can produce it so pressure will drop. This is why when you have a truck with 0 psi oil pressure you always pull the oil filter and hold down the drainback valve to see if it will fill the filter housing.

If this part still fails to make sence then gimme an idea of what you dont understand and Ill try to explain it more.

 

I see the truck is making LPO but blowing out HPO at a rate faster than the LPOP can feed the system.So it is pumping a volume of oil at 0psi.

 

yup exactly.
this is a common issue with the 03/04 build pumps when they blow the ball out of them.