Stumbling at idle after fill up, when do I need to do something?

[Capri to ST]

When I fill up I always just go to when the pump first clicks off, I never top up after that. Recently it has started stumbling or stuttering at idle the first time I stop after the fill up. It's getting a bit more noticeable, the idle will drop down and then go back up. Today it felt like it was going to stall but it didn't, it has never actually stalled. I know from many threads on here that this is something in the evap system, and I'm wondering two things-

1- How bad does it have to get before you need to do anything about it? and

2- I know generally it's usually some problem with the evap system, but exactly what is going wrong and more importantly what part or parts usually need to be replaced to fix it? Thanks all

The engine is stock except for the Mountune MP215 tune, and has a well-maintained 27,000 miles on it.

 

[Sam4]

Lots of info on this - D2BZ-9C047-E / https://www.bluespringsfordparts.com/oem-parts/ford-tube-fuel-feed-d2bz9c047e

 

[1nsanity]

I had actually replaced mines with the 2014 tube “upgrade” but the evap purge sensor ended up going bad in that one in less then a year? Went to my original 2 tube system to test as had initially thought it was my evap canister which took a hit a month or so prior with some road debris…

Crap location to have that cannister but meh.

The purge sensors fairly inexpensive themselves and just ended up doing what this member did. Just cut around it, used fuel lines and clamps and makes for an easy swap when the issue comes back so keep a couple of spares purge sensors in the car. Did the surgery last year and so far so good, though, I do leave the gas nozzle in for 2-4 minutes after it stops pumping which signals me to routinely take time clean windows and spot check fluids.
https://www.fiestastforum.com/threads/purge-valve-tube-pn-for-2019.24951/

 

[Fiestig]

I have had this since 8K and have never done anything about it 72K...lol. No problems when not at idle so I only notice it after initial fill up through maybe 2 stop signs or lights at most.

 

[1nsanity]

Mines just came on suddenly, otherwise maybe a handful of times that would stutter at startup after fillip. But that was early ownership before I caught on to the issue here.

Before the purge sensor went out, noticed mpg went down and was running a bit Lethargic. Then started throwing engine codes. Swore it was the evap canister at first as a month earlier took a hit and dragged a couple city blocks before I could pull over and check. Needless to say, have a backup evap canister as its location is out in the open, attached to the bottom of the fuel tank…

 

[Sam4]

mine popped on a couple of weeks back - its why I had the PN # close at hand. It's also the first time the light popped on - it's only been shitty idle up to now (125k). I'm digging around for the bosch valve I got from Rock, to make my own Frankenstein. I don't believe any check engine light will pass PA inspection, so I would guess I'm looking at assembly # 3, with Frankenstein for back up...

 

[Locke]

I have had this since 8K and have never done anything about it 72K...lol. No problems when not at idle so I only notice it after initial fill up through maybe 2 stop signs or lights at most.

Same, mostly. Stumbling after refueling started happening on mine pretty early on, somewhere around 10-20k probably. I never did anything with it. Finally a few years ago (140k+) it started stalling on me after refueling. I'm lazy and don't drive the car much anymore, so I still did nothing with it. Then just prior to a state inspection it finally threw a code and the throttle began to hesitate immediately off idle. I finally had to do something about it.

I replaced the valve only, using some hose I had laying around as a coupler. Fixed the code (of course), stumbling, stalling, and also the hesitant throttle.


OP: I don't suspect it is unsafe to leave it as is if you want/need to, but it is a very cheap and easy fix so I recommend just replacing the purge valve. It is located above the transmission, beneath the intake pipe.

 

[akiraproject24]

How long do you guys think these purge valve assemblies are good for when new in box and sitting in a spare bedroom?

Ive had a 14/15 sitting here for almost 2 years

 

[1nsanity]

It’s ironic, my original two line on a 2019 actually never failed. I bought the 2014-2015 single line new as a preventive measure and that failed in less than a year. Decide to replace the sensor as pictured.
Bought a handful of the sensors, keeping a couple in the car.

 

[FiestaSTdude]

How long do you guys think these purge valve assemblies are good for when new in box and sitting in a spare bedroom?

Ive had a 14/15 sitting here for almost 2 years

In the box? I would imagine quite a while. Why do you have so many?

 

[akiraproject24]

In the box? I would imagine quite a while. Why do you have so many?

I was going to swap to the older style and picked one up, only to end up with the Cobb intake which works with the newer version. I decided to run it that way but have been getting the occasional stumble now when it first comes out of storage so bought another '16-'19 version but the stumbling stopped after a rip on the highway with some BG 44k . Basically I have one of each kind on hand so not many.

 

[nfancera]

@Capri to ST - I had this problem forever and posted about it a few months back here: https://www.fiestastforum.com/threads/stalling-after-fuel-up.31708/#post-506362

Long story short, I ordered the pre-'16 Fuel Feed Tube and it resolved the issue. I ordered from here: https://www.tascaparts.com/oem-parts/ford-tube-fuel-feed-d2bz9c047e

I can't speak to everyone's experience and can't say I fully understand why this fixed the problem (they said something about a Venturi Effect allowing pressure to pull excess fuel from the line I think), but this has worked for me and solved the issue for the past 3 months.

 

[Sam4]

How long do you guys think these purge valve assemblies are good for when new in box and sitting in a spare bedroom?

Ive had a 14/15 sitting here for almost 2 years

Clearly expired - dry rot....

In the box? I would imagine quite a while. Why do you have so many?

I was addicted to ordering slider pin boots from Rock for a while there...My name is Sam F and I became an STholic in 2015....