HELLO, IM NEW TO THIS SITE. I RECENTLIY GOT A 2004 F150 FX4 WITH THE 5.4 3V ENGINE. THE PROBLEM IS WHEN THE ENGINE IS COLD, I CAN HERE WHAT SOUNDS LIKE A POWERSTEERING PUMP WHINNING. I REMOVED THE BELT AND THE NOISE IS STILL THERE AND IS COMING FROM THE FRONT OF THE ENGINE. ALSO WHEN THE TRUCK WARMS UP, IT DEVELOPES A TAPPING SOUND THAT GETS WORSE AS THE TRUCK GETS HOT. ALSO WHEN YOU ARE DRIVING THE TRUCK AROUND 55 IT WILL LOOSE OIL PRESSURE. IF YOU SHUT IT OFF AND RESTART OIL PRESSURE IS BACK. IT ALSO SOUNDS LIKE A DIESEL ENGINE ONCE IT HAS BEEN DRIVIN FOR APPROXIMATELY 35 MIN. I HAVE REPLACED TIMMING CHAIN TENSIONERS, CHAINS,GUIDES AND INSTALLED A NEW OIL PUMP. STILL SAME PROBLEM. THERE ARE TWO CODES WHICH ARE P0340 AND P0345. IF ANYONE CAN HELP I WOULD GREATLY APPRECIATE IT. IVE HAD THIS TRUCK FOR 6 MONTHS AND ITS DRIVING ME CRAZY.

 

Also i see there are alot of issuse with the 5.4 3v are they good engines, or should i see about getting rid of it and go back to the 4.6?

 

This will solve the noise issue and poor running:
http://www.obd-codes.com/p0345

Most likely the sensor is bad. I assume that while you had the engine apart you checked the pick up screen for the oil pump and made sure it was clean. It has a tendency to get sludged over on engines not seeing good maintenance and on others that see short drive cycles. The issue could also be a bad sending unit. If you have a mechanical gauge that you can install on the engine while you drive would be helpful. The Tritons are a great engine but the 5.4 has seen lots of issues with the cam phasers. It's important to use the correct viscosity oil if you want it to work correctly. The system is oil pressure activated and using a heavier viscosity will make the timing advance before it's design criteria. Ford recommends a 5w-20 for your engine and just make sure it has the Ford spec on the back of the bottle. Use a good, name brand filter too. I've seen filters give the same issues as you're having with sporadic oil pressure loss. Motorcraft and Purolator are good ones.

 

Thanks for the tip, yes the previous owner did not keep up with maintenance, I did check the pick up tube and it wasnt plugged. There was some sludge in the motor but nothing severe from my point of view.(could be wrong) Right now Im using amsoil 0w20 full synthetic with a amsoil oil filter. Do you know if bad cam phasers can cause it to loose oil pressure. I picked a mechanics brain from my local ford dealship and they said it was possible. Not to sure if I belive it. Thanks for your help again. Also the truck has 86000 miles on it

 

The cam phasers CAN cause the oil pressure problem but it's not likely. Considering that you know the engine has some sludge in it, you're using probably the worst oil. The Amsoil ASM has a good amount of PAO in the formulation. It has lots of solvency. I can assure you that it's cleaning the engine and quick. Your problem may actually be the filter going into by-pass or being sludged so much that it can't get into by-pass. I'd suggest changing the oil to something less exotic and a common filter until you've changed it a few times to unload the sludge you already know about. Cleaning an engine too fast can be more catastrophic than leaving alone. Auto-Rx is made just for engines like yours. It's a slow cleaner and won't strip lubrication like a quicky flush. Frankly, I would run a dose of that thru it and then follow up with the rinse phase before putting the Amsoil back in.
Have you put a mechanical oil pressure gauge on it to know that you actually are losing pressure? These sensors are known to fail and at 80,000+ miles it's highly likely it's also sludged up causing the possible false reading. Unless you have put a mechanical gauge on it, yer guessing.

 

Wow, Thanks for the info, Can you get the Auto-rx at a local parts store? Im going to try that. No I havent put a mechanical gage on it yet. I will say I belive you on a bad sensor because I have noticed the oil gage on 0 while driving and no abnormal noise coming from motor before I shut it down. Just the annoying diesel sounds at low speeds. Im going to put a mechanical gage on this weekend.

 

Before spending money on a mechanical gauge and figuring out how to add it in, you might want to just try replacing the OEM sending unit to see if it's the problem. It's a cheap part (under $20 for my truck). It's basically a NPT threaded adapter with an electrical plug on the back, assuming they didn't change too much about it in the 3V engines. Drain the oil and access to the sensor is easiest while the oil filter is off.

BTW, Ford lists the part as an "Engine Oil Pressure Switch".

Good luck!

 

I'm having many similar issues. Have you resolved any of yours?

 

Getting same codes.. 2005 FX4 167k
Any new on yours?

 

I have been through all the throubleshooting on this engine and let me tell you this. If you are having noise from the phasers, broken timing chain guides, sounds like a diesel, sounds like powersteering pump whine, oil pressure gauge goes to zero intermittently. THE OIL PUMP IS THE CULPRIT!! The oil pressure gauge is a dummy light in disguise. It will read normal untill it gets down to 5 psi or so.these engines maintain upwards of 70 psi at highway speeds and at least 25 psi at low idle. Thats a lot to ask from a pump long term. My suggestion would be to watch everything on YouTube about this engine. Inspect the phasers, replace the timing chain set, replace the oil pump. While the front cover is off flush the oil pan and pickup tube with diesel and let the sludge drain from the oil plug. Reassemble and be done with it.