Ok I have done alot of research. Well I am working on a truck that has that diesel sound between 800 and 1200 rpms the motor had a timing chain brake couple years ago and they fixed it all ran great for two years it was passenger side that broke. Well on driver side it's getting diesel sound unplug vct problem goes away. Plug back in comes back. So most say solenoid could cause it. I replaced vct and as before once engine warmed up the motor would get that sound at feather throttle. But not as bad and for a while it was good but slowly came back. Is this a cam phaser? All noise is not there when cold or vct is not plugged in. Would it be good idea to try to change oil and filter first then go to cam phaser? Any help would be much appreciated at times it is also intermittent. No check engine light. But does stutter intermittently once vct is in use also found a wire at back of drivers side valve cover exposed possibly broke could that wire be causeing the issue? Read on Internet somewhere that could be a possibility

 

Well actually found out today noise never left but for 20 mins the more it gets hot and longer you drive it the worse it gets has hole new timing chain set two new vct solenoids and I was also told it has the camshaft phasers new as well so what could be causeing it to slowly start doing this as the engine gets warmer and hotter engine oil looks clean.

 

Sometimes a dieseling noise will be caused by a loose cam timing gear bolt. If the bolt was not torqued right and loosened or if the bolt was cross threaded and achieved torque but did not set completely the washer will rattle just like a diesel engine. I have seen this many times. Also lash adjusters that are collapsing from lack of oil pressure on either cyl head will sound like a diesel engine as well and a chain tensioner collapsing can do the same. A stethoscope can help you determine the exact location of the noise and that will help determine the component responsible for that noise. Anytime an engine has had internal work performed there is a chance the repair was was not complete, a oil galley plug was left out or one added where there should not be one. Good luck.

 

Thank you for your reply I do appreciate it I have traced the problem down to passenger side valve train or possibly phaser or valves unplug vct solenoid sound goes away tried driver side no change engine has severe miss when it starts occurring. Un plug goes away tried taking the vct solenoid from drivers side and installing in passenger side no change. When you unplug vct on passenger side stops making noise. Plug back in it comes back. I Am Taking It To A Dealership tomarrow. While swapping the vct solenoid I did notice that the vct solenoid was not tightened so I find it highly possible the bolt very well may be loose on the phaser to cam or the other suggestion you have brought up. I did not work on it originally. I am a diesel technician learning all about this new variable cam timing system. Much appreciated. The cam phasers where replaced a year ago. Hopefully the dealer can diagnose and fix it. Truck has plenty of power. Runs good up until point it gets warm. Then miss stutter and valve noise. Between 800 1200 rpm. I just do not have all the tools and diagnostic procedures to test and properly diagnose the problem. Chain does look tight I pulled seal out of driver side valve cover watched timing chain did not seem to be slapping or loose. But I didn't try to see if cam phaser was loose on the cam.

 

Oh and I did also notice alot of oil flowing around the cam area of the head near phaser not sure if that's normal.

 

Took it to ford today they hooked the computer to it the technician told me it is advancing and retarding the timing way to fast 60 degrees one way and the other. and causeing a predetonation they say there is something mechanical causeing it any ideas where this could be? Could it be one of the cam phasers a tooth off or? Can it be what you suggested earlier?