I have an 05 F150 5.4 I bought on craigslist 2 years ago, and still looking for answers. I bought it with a broken timing chain guide for a steal. Replaced all timing components, with new OEM Phasers. Well after running it, it diesels like hell at 800rpm on decel back to idle when hot, because the phasers aren't locking most likely due to less than 25psi at operating temp idle.

My question is, besides a CEL, is it ok to run the truck with the soleniods unplugged, so the phasers stay locked?

 

I'm assuming you replaced the solenoids when you did the work? If you did, did you also take the oil pan off and clean the pan and sump screen of any plastic pieces of timing chain guide? When guides break, the pieces go down in the oil pan and can get sucked up by the sump and block oil flow and can cause this problem.

And yes, you can drive it with the solenoids unplugged. The cams I believe will just stay locked at full advance position (idle).

 

Yes, I replaced the solenoids, dropped the pan and pickup tube, cleaned both, did 3 oil changes, 2 sets of cam phasers. We ran a pro snap on diagnostic tool that showed the timing wasn't returning to the locked postion at idle after operating temp. I read about 10 hrs of forum threads and watched a you tube video where the oil was leaking off a cam bearing when warm, and heard the thrust bearings go on the crank. I'm just not willing to do an engine rebuild for as much trouble that these motors have to just fail again, and not dropping $3500 for a new one on a $4200 truck.

If I can run it with unplugged solenoids, and lose a little power with the CEL on, I'm fine with that as I only drive around 5k a year with my trucks as a 2nd vehicle for building supplies and towing stuff to the dump. If I can run it as without doing any engine damage for another 20k miles, I'll be happy. My 98 f150 has 310k and falling apart, so I'm wanting to switch over to this truck asap.

 

Yes, it should be fine without the solenoids being plugged in. One thing I forgot to ask; Did you replace the oil pump along with the timing set? It's not too often that they go bad. However, they have been known to fail on these engines and it's good to replace it when you're in there replacing the timing components.

 

I didn't do the pump, because at the time we saw the broken guide and just replaced all that. I don't belive the pump is bad because the gauge is where it should be and I hate throwing parts at a problem.

 

That gauge is a FRAUD. It will be where (as you say) it should be if you have ANYTHING over 5-7 lbs of oil pressure, and it NEVER moves all over the place like actual oil pressure does. It is nothing but an analog representation of an idiot light.

 

That's true. I will hook up a gauge when its not freezing out to confirm.

 

I agree with @07F150Lariat5.4. The cams/engine will suffer no ill effect mechanically from your running with the VCT Solenoids unplugged. Only, as you say, permanent loss of retard functionality and a constant CEL.


However - disconnecting VCT Solenoids should NOT have the effect you are seeking - unless something else is wrong. IF you have dieseling noise from Phasers - WITHOUT a DTC, - disconnecting VCTs cannot possibly stop the diesel noise. OEM Phasers 'lock' at base position by a spring loaded locking pin inside the Phaser when the Phaser returns to Zero degrees. They should return to zero by virtue of the PCM applying NO DUTY CYCLE pulses to the VCTs (ie: just like unplugging them) - thus routing 100% of available oil pressure to the Phaser Advance chambers. If oil pressure lacks sufficient strength, the Phaser 'clock spring' should provide the additional force needed. If BOTH are insufficient to return the phaser to Zero degrees - THAT would suggest to me TOO MUCH rotational 'drag' or resistance exists in cam bearings, roller followers or somewhere. You should also be getting a DTC 0012 and/or 0022 - over retarded under that scenario.


Once the spring loaded locking pin inside OEM Phaser captures and locks the phaser at zero degrees, it requires oil pressure ABOVE a certain threshold before they will UNLOCK to allow Retard again. Retard is NEVER requested by the PCM below 800 RPMs or 25% engine load. So below that point (at idle) - no voltage (duty cycle) is being applied to the VCT Solenoids. Unplugging them has NO effect. If one is stuck partially open - unplugging it will not make it 'un-stick'. (Wrap on it instead).


The electrical configuration of the two wire VCT circuits are: Positive voltage is wired to one side (hot all the time) - and the PCM actuates VCTs by providing ground on the other wire. IF unplugging them makes a difference - AT IDLE -, it must be due to SOMETHING causing current to flow in the wire going from the VCT to the PCM - thus holding the solenoid partially open and feeding oil pressure to retard chambers.


If you have 'dieseling' noise from slightly low oil pressure (which I suspect is the case since oil pump was not upgraded) - the noise is most likely the result of Chain Tensioners unable to hold enough tension against the chains - allowing slack to develop in the chains - THEN the 'HIGHLY IRREGULAR' torque required to rotate cams lobes against the uneven resistance of two intake valve springs and one Exhaust valve spring per cylinder - causing the chains to slap up and down on the guides and work the slack in the phaser locking pin back and forth against both ends - 5 times per second (about 300 rpms).


Unplugging VCTs will not change any of that.

Just some thoughts

 

I have no noise from the phasers, just the phasers not locking into idle position at operating temperature. Thank you for the info.

 

I misinterpreted your meaning here.


How are you determining phasers are not returning to base position (and locking), based on VCTERR and/or VCT2ERR - PID 16CE and 091D??

 

I based it off the truck sounding like it would explode on decel to a stop and I could rev to 2k and release to get it back to lock sometimes, then watching timing on a snap on scanner. If i unplug the soleniods it runs perfect.

 

That DOES sound like it takes extra 'oomph' to push the phasers back to advance position. The PCM will not request retard (or activate VCTs) by revving one in neutral at a stop - but running RPMS up will definitely raise oil pressure. So the effect would be to drive additional pressure into the advance chambers. With VCTs unplugged - once the locking pin captures phasers at full advance, there is no signal to ever release them.


I will be curious what you find with an analogue Oil Pressure gauge.


EDIT: I do not understand why that doesn't cause a DTC. Specifications indicate > 5 degrees cam error ("+" or "-") for > 5 seconds = DTC, over retard or over advance as appropriate.

 

Dunno what DTC is but I got a code saying a solenoid didn't work, which we swapped in the old ones, same code, then switched sides, same code. Can't run it long with them plugged in to play with cause once that chain starts slappin, I shut it down.

 

"D"iagnostic "T"rouble "C"ode. The code you got saying a solenoid didn't work. Presumably - P0012 or P0022.

 

My buddy had it on the scanner a while ago. I'm used to calling them a CEL code. Anyways my guess is my idle oil pressure us less than 25psi which I read about a lot.