What is normal oil pressure for a 5.4? I just installed a Autometer electric oil pressure gauge in my truck and this is what i get.
Idle- around 35psi
1500rpms- around 65psi
4000rpms- around 85psi
Im wondering if my sending unit is messed up, because when i first got my gauge installed it was telling me i had 75psi idleing and 100psi at like 3500rpms. Then i went for a drive, and now it is telling me pressures that are more realistic.

 

It takes awhile for the oil to heat up idling which is why the original pressures were so high I would think.

 

I was thinking about that, but its wasnt cold here, once i got the gauges installed it was at least 75 degrees. Also i had started it a couple of times after putting the sending units in to check for leaks.
I will check the pressure again this morning when i start it.

 

Why did you have to install an OPG, don't you have a factory one?

Just kidding, how did you get the OP signal to the sending unit? Did you use a
(is yours the electric type - non mechanical - that is?)
T fitting at the factory location?

I want to install one on my 07 Explorer, but I can't seem to figure out a location to install the sending unit.
Plus the 07 4.0 sends the OP info to the computer, then to the dash light.

 

No i didnt install a t fitting, i just got rid of the factory sender and installed the autometer sender. But as you said your 07 will need you to use a t-fitting probably.

I went and started my truck again and it went to 75psi idling and didnt drop.. im going to get ahold of Autometer and see if they could send me a new sender.

 

Bump..does anybody have any idea why when i first start it the oil pressure is real high, but then a little while later it works normal..?

 

LxMan1 told you.
What you're seeing is normal. At startup,the oil pressure is high,and the bypass is dumping excess pressure back to the pan,but it cannot dump all of it,so you see more pressure on your gauge. As it warms,the bypass operates less,and you see a lower pressure as the oil thins out.
JL

 

Not to sound ignorant, but where is the bypass at...in the filter?

 

Take a look at this

FL-820S Oil Filter Alternatives

Click on blue letters to go to linked site

 

Oil pump.
JL