Idle stumble after refueling
03-16-2019, 12:15 AM
#1
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Idle stumble after refueling
I have noticed that after fueling, when I restart I have developed a stumble or surge in idle. Has anyone else experienced this problem? It goes away rather quickly, like within 10 minutes. Has me stumped.
2016 supercrew, 2wd, 2.7 ecoboost. (52,000 miles)
2016 supercrew, 2wd, 2.7 ecoboost. (52,000 miles)
03-16-2019, 05:54 AM
#2
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Since it seems to be temporary at refueling, as a guess I would say it's due to increased vapor pressure. Things get stirred up causing light ends mixed in the gasoline like butane, even ethanol to evaporate more quickly in the fuel lines. Once they pass through back to normal? Is it more noticeable in winter? Do fuel lines run close to the exhaust or engine causing a little old school vapor lock?
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tdog02 (03-16-2019)
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tdog02 (03-16-2019)
03-16-2019, 10:20 PM
#5
This this is what I think. Every time you fill up you emulsify that water into the gas which doesn't like to burn very well in the engine and then it settles out to the bottom of the tank again waiting for the next fill to get churned up again. It only takes filling up at a gas station with bad gas once to cause repeat issues.
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tdog02 (03-16-2019)
03-16-2019, 11:34 PM
#6
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I remember reading about an emissions evap canister or solenoid that may have to be replaced but I can't remember where I read that. It is comforting to know I am not the only one but there must be a simple fix for this?
Interesting theory SSowinski, I hadn't thought of that but it makes sense. I was worried it was evap emissions related or possibly a heat soak issue, I'm still stumped.
Interesting theory SSowinski, I hadn't thought of that but it makes sense. I was worried it was evap emissions related or possibly a heat soak issue, I'm still stumped.
03-17-2019, 12:06 AM
#7
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Any water that is present in the fuel (usually none) will settle to the bottom of a fuel tank. Fuel pumps also pull from the bottom of a fuel tank. In the rare event that water is introduced into a vehicle it is brought to me on a tow truck. Water doesn’t stay suspended in fuel, it stays separated and settles. So this will not be the cause of a misfire.
I must first disclose that I have not attempted to diagnose a misfire only after fuelling. This will be difficult to confirm which is the very first part of diagnosis. My best guess would be that fuel mixture strategy is being adjusted to accommodate for the burning of vapor stored within the canister. When pressure is relieved the fuel strategy is then inaccurate until stabilized. Perhaps a malfunctioning vent solenoid sticking closed? I stress the work GUESS, but I’d love to take on the challenge of diagnosing this, hopefully not to conclude an engineering fault....
I must first disclose that I have not attempted to diagnose a misfire only after fuelling. This will be difficult to confirm which is the very first part of diagnosis. My best guess would be that fuel mixture strategy is being adjusted to accommodate for the burning of vapor stored within the canister. When pressure is relieved the fuel strategy is then inaccurate until stabilized. Perhaps a malfunctioning vent solenoid sticking closed? I stress the work GUESS, but I’d love to take on the challenge of diagnosing this, hopefully not to conclude an engineering fault....
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tdog02 (03-17-2019)
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03-17-2019, 01:25 AM
#8
Tapping fuel off may cause all sort of issues related to evap system and idle. Never tap fuel off. If raw fuel gets inside evap hose, it will mess up evap solenoid. Idle may be rough plus ecu may throw out evap error codes.
Friend of mine was tapping fuel off periodically. Evap system mulfuctioned costing him an expensive repair.
If you suspect a water presence in your fuel tank, add Amsoil Quick Shot, it will dispurse water molecule within fuel, plus it will clean fuel injectors and intake valves (port injection).
Friend of mine was tapping fuel off periodically. Evap system mulfuctioned costing him an expensive repair.
If you suspect a water presence in your fuel tank, add Amsoil Quick Shot, it will dispurse water molecule within fuel, plus it will clean fuel injectors and intake valves (port injection).