Stall when coming to a light ONLY after filling tank

[Maihyo]

This is an odd one. I did a search and couldnt find anything relevant, though I'm sure theres a post somewhere on this. Immediately after filling the tank when I come to my first stop the idle will come down to 800 like normal then just keep going down until it stalls. It only happens one time at my first stop after filling my tank and its only happened twice since I've owned it. A more regular occurrence is it will drop to about 400rpm then kick back up to normal only once after filling. I feel like its an air bubble in the fuel line but that seems unlikely. I put cobbs ots stage 1 91octane tune on it within 3 days of purchasing so it has only happened with the tune. I wonder if its something related to cobbs ots tunes. I wouldnt really call this a problem as it almost never happens but I wanted to see if any other FiST owners have noticed this.

 

[Hypergram]

Yep. This happens on a lot of Fiestas including mine. Particularly when it was new. I may be wrong, but the reason it happens is that the sensor near the tank entrance "smell" gas fumes after a recent fill-up. "It's a known issue with capless fuel tank. You're suppose to leave the nozzle in the tube after it stops filling for about 5-10 seconds before you slowly take it out. Page 121 of the manual. This happened to me once when I took out the nozzle too quickly. I've been conscious of this and hasn't happened since."

https://www.fiestast.org/forum/fiesta-st-performance/2371-fist-stalls-out-after-fill-up.html

 

[Maihyo]

How interesting, thanks for the info! Guess I'll let it sit in there a bit longer before I pull it out lol

 

[DEss]

Likely evap canister or purge valve - couple of old threads on this issue. Do you top off?




DEss

 

[s4uce]

My fist is quite new with 3000km and I get it on start up if it is already warmed every time. Sometimes at lights. I noticed it once I put my rmm in since it makes the car shake like crazy below 800 rpm

 

[HBEcoBeaST]

i ordered the evap fuel line assembly and it fixed the problem.

 

[kivnul]

As already mentioned, it is a pretty common issue. Leaving the nozzle in the car for a few seconds after the pump auto-shuts off can help. Never force more fuel in / top off the tank once it clicks. The evap purge valve is usually the culprit if the above 2 things do not help you. There are several posts around on this forum that talk about this in much more depth.

 

[HBEcoBeaST]

As already mentioned, it is a pretty common issue. Leaving the nozzle in the car for a few seconds after the pump auto-shuts off can help. Never force more fuel in / top off the tank once it clicks. The evap purge valve is usually the culprit if the above 2 things do not help you. There are several posts around on this forum that talk about this in much more depth.

all the wiggling, not topping off and leaving the nozzle in made me look crazy at the pump. and it didn't work. :-( weird how some cars are not affected and others the evap purge solenoid valve just dies