*Update 04/28/21 - P0456 DTC and collapsed fuel tank example w/temporary emergency fix on post #72
*Update 05/22 - FUFF 2.5
Part 1:
So I was this contemplating just how I was going to approach this particular topic. Do my normal overly technical explanation? Start off with a meaningful antidote or compelling story to help the reader relate to the topic at hand? No, because of the amount of headaches that this part inflict's on our community this statement will mostly be accepted by those that read it.
**** Ford, their engineers, accountants and for the EPA's constantly moving the "clean air" goal post whenever the hell they feel like it.
Okay so while I work through my anger issues let's talk about the bane of a ST owners existence. The EVAP purge valve sits just next to the engine near the vacuum and high pressure fuel pump. It's job is to release excessive fuel vapors that naturally build in the fuel tank. When it works correctly that is. When it's doesn't it induces rough idle, stalling, or deformed fuel tanks.
The Focus ST models here in the USDM use assembly part number BV6Z-9D289-E. This part normally retails for roughly $65 USD before tax and shipping. The one I recently ordered cost $73 USD shipped from my local Ford dealer. Other models of Ford focus, including the AWD RS use this valve that can be found for less than a third of the ST assembly but will not fit the ST's configuration.
This valve itself is very simple in function and extremely cheap in it manufacturing quality. A quick disconnect fitting just above the throttle body on the passenger side of the intake manifold runs up and through a one way check valve that prevents a positive pressure (boost) from damaging the evaporator system. The nylon fuel hose then runs across the intake manifold and turns back towards the rear of the engine on the drivers side terminating at what would be concerned the purge valves output, or the portion of the valve that see vacuum.
The inlet of the valve has a similar, yet shorter section of nylon fuel line and quick disconnect fitting that attaches to the metal line leading back to the fuel vapor canister.
The theory therfore should be that vacuum pressure alone should be able to keep this valve closed unless acted upon by an outside force (in this case the PCM commanding the valve open via a 12 VDC electromechanical solenoid.) However the issues begin to arise whenever this valve allows manifold vacuum to escape past the sealing surface of the valve pulling a vacuum at idle and cruise. This can result in rough idle, strange rich/lean AFR, stalling randomly or immediately after refueling, P03XX codes (random cylinder misfires) and worst-case scenario it can cause the deformation of the fuel tank.
Safety recall 18S32 (*see attached PDF) covers the fuel tank deformation but little more than slap a bandaid on a sucking chest wound.
Also in Ford's infinite wisdom their "fix" includes a PCM calibration that will update the PCM to a newer model year doing two things 1. It eliminates the .040" evap leak test, leaving only the .020" test making the issue more likely to occur and 2. Leaving those of us who use aftermarket tuners such as the Cobb Accessport unable to reinstall our tune without assistance from the either Cobb or the individual tuner.
And best of all the this "fix" did zero to address the problem so you will continue to experience the failure. But hey, Ford did their part right?
So this leaves our community to look after it's own. Again.
Let's start with location and removal of the offending items from the vehicle. This can be accomplished with a few basic tools in a short time.
Start by loosening the hose clamps from the air box and upper intake pipe. You can use either the appropriate hex socket or slot-head (flathead) screwdriver.
Next remove the single 8mm bolt holding the upper intake pipe to the engine. The upper intake and flex section to the airbox can now be removed.
Locate the purge valve and electrical connector between the engine and battery box.
Carefully lift the locking tab from the connector from the valve body and lift upwards.
Inspect the connector pins, wires, & moisture seal for damage. Clean or replace accordingly.
The valve is supported by a rubber isolator and steel bracket. The bracket is attached directly below the HPFP (high pressure fuel pump) by two (2) 13mm nuts. Using either a deep well socket or standard socket and short extension. I found it was easier to break both of them loose and remove them by hand to prevent dropping them. I really didn't want to pull the lower pan.
Starting at the rear of the engine and using a small pick or screw driver carefully pry the quick disconnect locking tab away from the QD connector. Again pry carefully as this lock can be easily broken, especially when the temperature is below 50 degrees fahrenheit.
Once the lock has been disengaged press the QD button and lift away from the steel line. You may need to wiggle the connector slightly in order to allow its release.
Detached the evap tube using a slot-head screwdriver or pry tool by carefully lifting the 3 supports from the intake manifold.
Next is the most difficult portion of this removal in my opinion due to the tight space between the QD and manifold. The lock is identical to the previous connector and will need to be pried away to allow the connector to be removed. Take your time! A new intake manifold is $68 at the time of this write up.
That's it. The EVAP purge valve assembly is now easily removed from the engine. But what to with it is the real question. Yes you could simply replace the entire thing for a full price unit but what's the fun of that?
Continued in part 2
