I have a 2004 5.4 3v with low oil pressure. I have replaced pump, phasers, chain, guides , sensor and even the crank shaft bearings. I put a dial guage on it and still no oil pressure.. Help please!

 

What is the warm idle oil pressure? What does it go to when you rev it up? Did you use OEM timing parts and a Melling high volume oil pump?

 

I used a mellings oil pump but aftermarket timing parts. At 2k rpm i have good oil pressure but when i decelerate it drops down to 0 oil pressure

 

I doubt it's really zero - if it were, the engine would be making a lot of noise and would have a very rough idle, if it even kept running. What weight oil is in there?

Aftermarket timing parts are no good.

 

Sam, I moved your thread to a forum where it might get more visibility. I agree with glc regarding the oil pressure at idle. A very low viscosity oil might be causing your problems. As glc asked, what weight oil are you using?

- Jack

 

I use a sae 5 20 weight

 

Is it idling quiet and smooth? If so, your gauge is incorrect. Without oil pressure, it would be rough and noisy.

 

The engine is quiet.. Very quiet... That's what driving me nuts. I drive it on the interstate and not one noise. Heck my gas mileage is 19.2 at 78mph. But as soon as i drop down to rpms to below 1.2 the oil pressure gauge goes low oil pressure

 

Then your gauge is incorrect. Is that too difficult to accept? If you had low oil pressure at idle, the phasers wouldn't be operating correctly, the idle would be very rough, and it would be making all kinds of noise.

 

then off i go to replace the gauge.. I will check back in after i replace it.. Thank you for for advice. I totally appreciate it.