Hey guys, any input would be helpful here. I have a 2004 f150 5.4 3v. Been through all the cam phaser vct solenoid issued with no progress. New phasers, solenoids, guides, chains, tensioners, and oil pump with no change. Still getting knocking on pass side and runs really rough when warmed up. Ran it with the solenoid out looking through the hole seems to have good oil flow so tested the voltage from the plug on both sides. The driver side was getting voltage, but low to none on passenger side. So the im figuring that must be my problem since theres no power to open it and let the oil in? Traced through the harness and found no breaks or shorts. Possible bad PCM? Just wondering if anyone else has experienced this and may know the cause before dropping big $ to MAYBE get an honest answer from a mechanic. Thinking maybe locking out the phasers might be my only option.

 

@Mikesqm900
Very sorry for the persistent problem after the work you have done. My outcome was the total opposite - thank goodness. Doesn't mean I any sort of genius and you aren't - and I'm no expert or mechanic, but at least honest. I am happy to share all I do know about the 5.4 with a fellow F150 Owner. Answers to some questions might help get better answers.
Any Codes? OEM Parts used? Did you remove Pan & Clean pickup tube screen? Total miles on the engine? Can you describe the 'knocking' on passenger side better? Were lash adjusters / Roller-Followers replaced? Has a good (Wet/Dry) compression check been done to make sure rough idle is not a weak cylinder?

Generally though: The solenoids are designed to pass 100% of the available oil flow straight through them to the tensioners and Phasers when no signal is being applied (ie: NO RETARD - Full and locked Advance position). That is the status always at idle. NO RETARD is applied by the PCM below 800 RPM and/or 25% engine load. Therefore, you should generally see NO signal when you are under the hood 'tinkering' with it. AND, unplugging the VCT Solenoids should have NO effect if there is not a Short in the signal wiring or problem within the PCM. Unplugging them has the effect of TOTALLY disabling VCT Operation, theoretically the same as installing LockOuts. The exception being, if the Phaser clockspring + available oil pressure is insufficient for the Phaser to overcome camshaft bearing/valve train drag. Then the pahsers could sag toward the retard position. ((PS. I wouldn't run one with VCT uninstalled. That insures ZERO oil pressure is reaching the chain tensioner!!))


As to the VCT signals: It is difficult to test/diagnose without a scanner because: The Red/Yellow wire is sourced with positive voltage all the time, and the other wire (Violet/Blue on Bank 2) and (Dark GRN/ORG on Bank 1) is pulled LOW by a "SQUARE WAVE" duty cycle signal by the PCM. It is difficult to measure without an O'Scope. But it NEVER happens below 800 RPM and 25% engine load anyway. So that is futile unless we put you under the hood and go for a drive. LOL


I am more concerned about isolating the knocking sound at this point. If it is a bum lash adjuster, or sloppy lifter- could be degrading the aspiration of one cylinder. Also, I replaced all my lifters and roller-followers AND all 8 Injectors, so I am somewhat biased. But I actually attribute the smooth quiet idle on mine to the new injectors. But I know of NO way to check them for proper calibration or flow rate.


Hope this gives you a couple of new, useful ideas. Good luck

 

To the OP, Torqued has brought up some very good points that you need to investigate. I also believe that you have other issues other than VCT solenoids.
As stated, we need more info-codes, etc...





There are ways for those with some tinkering ability...

 

Well its running smooth as silk now, misfires turned out to be a bad connection on the plug feeding the cop on #5. Changed it out, runs smooth. Still having problems with the phaser knocking, isolated the noise, coming from the phaser. I think my next project will be to swap the solenoids around to see if it follows. They are new but have had new electrical parts fail immediately before so worth a try. Thank you for the input on the issue, very helpful.