5.4L PHASERS/VARIABLE VALVE TIMING technical question - Degš. Advance?

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Old 05-10-2015, 12:09 PM
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Question 5.4L PHASERS/VARIABLE VALVE TIMING technical question - Degš. Advance?

The PHASERS start out at one extreme position of NO RETARD, and are actuated only one in direction - toward a maximum RETARD.


The ECU achieves a desired (or requested) VALVE TIMING "RETARD" by applying a voltage (by duty cycle between 0 to 100%) to the VCT Solenoids.


With NO requested retard [no voltage (Zero duty cycle) is being applied to VCTs], the phaser "return spring", along with the VCT Solenoids routing oil into the proper PHASER chambers, the phaser vanes are pushed to the "DEFAULT" cam timing - or "ADVANCE" position. Another way to express it is, to the maximum "NO RETARD position". This is the relaxed, or engine off, or startup, and idle position. See image number four in these great photos: 5.4L cam phasers.. What goes bad? - Ford F150 Forum - Community of Ford Truck Fans


MY QUESTION IS: In this "DEFAULT" state or position, how many degrees "ADVANCE" is the camshaft actually at? I don't believe this unidirectional adjustment accommodates NO advance at all. I know some camshafts can actually be ground with a few degrees of advance - but I'm not asking about this. The question has to do strictly with actual camshaft positioning with respect to the crankshaft, either in "camshaft degrees" or "crankshaft degrees" (which is twice that of camshaft degrees) so long as I know which.


The Phaser design seems to provide maximum adjustment capability of about 35-38 camshaft degš, or 70-76 crankshaft degš. [[ 1/2 of each of 5 phaser chambers ((360š/5)/2) ]] See photos in above link?


REASON FOR QUESTION: I have identified and isolated four unpublished PIDs available from the ECU on my 2004 Ford 5.4L 3v that give real time operational data concerning the variable valve timing system. I have the parameters working on Custom PIDs and custom gauges to read these PIDs on the TORQUE PRO application. But, for one, being RETARD REQUESTED by the ECU (In Cks Degš), I need the proper "offset" (in degrees) for my formula to make the gauge accurately read camshaft position across the full range of ECU requested retard.


These unpublished parameter ID's are probably there for the FORD Dealership's diagnostic equipment, and as prevalent as problems are with phasers, I want to perfect my formulas. If someone can help answer this question, I will provide information for inputting these four Custom PIDs into the TORQUE PRO APP. If anyone is interested they are:
1) VCTENA - Conditions correct for Variable Valve Timing operation.
2) RCAM - Requested Cam Retard (in crankshaft degrees)
3) CAMDCR Commanded Duty Cycle for VCT Solenoid (in %)
4) CAMERRR VCT CAM Error (in Crankshaft Degrees) [[ plus or minus degrees that cams are OUT of sync with requested retard - this parameter "leads to" cam position DTC codes (P0011, P0012, P0021, and P0022).


Thanks for information any technical or engineer type can provide regarding "5.4L CAM ADVANCE in the default phaser position"
 
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