2019 Fiesta ST Gas Problems

[Shepherd27]

Bought my 2019 Fist in August 2024 at 101k miles. Car runs good but since purchasing the vehicle, ive only been about to fill the tank to about 3 quarters. After a few fills, I went out of town for about 8 days and the car sat in my garage. The next time I went to fill the tank, it let me fill up all the way to the full gauge. But now about a month or so later, it is back to being full at 3 quarters. The low gas gauge will sometimes come on, but when turning the car back on after a night, it will be back to full tank. Im usually only able to fill about 8 or maybe 9 gallons but I believe the capacity is 12. Anyone have this issue before or know what it could be? Thank you.

 

[Intuit]

Capacity is 12.42 Gallon (47L).

Had 101k on it back in August, how much now?
Check the ground connects to and around the battery.
"Voltage drop testing" helps identify weak connections. All circuits must be fully loaded for an effective test result. A loss of 6% or greater is considered excessive.

The fuel level sender appears to be mounted on the fuel pump, which is inside the fuel tank.

RCM = Restraint Control Module (seatbelts?)
FPDM = Fuel Pump Driver Module

 

[Intuit]

They don't make it easy to get information on the fuel gauge.

 

[Intuit]

The "2016 Ford Fiesta ST - Service Manual - 413-01 Instrumentation Message Center and Warning Chimes.pdf" is too much to post, so has been attached. But this will provide a diagnostic chart for pin pointing the issue.

 

[dhminer]

How’s your battery? Rule number one with this car - it does weird shit when the battery isn’t in great shape

 

[Shepherd27]

How’s your battery? Rule number one with this car - it does weird shit when the battery isn’t in great shape

Will check it, thank you

 

[Shepherd27]

Capacity is 12.42 Gallon (47L).

Had 101k on it back in August, how much now?
Check the ground connects to and around the battery.
"Voltage drop testing" helps identify weak connections. All circuits must be fully loaded for an effective test result. A loss of 6% or greater is considered excessive.

The fuel level sender appears to be mounted on the fuel pump, which is inside the fuel tank.

RCM = Restraint Control Module (seatbelts?)
FPDM = Fuel Pump Driver Module

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At 108,600k miles since buying it late August. Thank you for this valuable information! Im not super mechanically inclined myself but im gonna start with the basics and maybe get someone to help with other stuff. Another thing ive been experiencing is the car sometimes randomly feels as if its about to stall when idling. The rpm starts to drop all the way down then comes back up, hasnt stalled yet . Thank you

 

[Zeille]

At 108,600k miles since buying it late August. Thank you for this valuable information! Im not super mechanically inclined myself but im gonna start with the basics and maybe get someone to help with other stuff. Another thing ive been experiencing is the car sometimes randomly feels as if its about to stall when idling. The rpm starts to drop all the way down then comes back up, hasnt stalled yet . Thank you

sounds like an EVAP purge valve issue, would be worth going to replace sooner rather than later

 

[Shepherd27]

sounds like an EVAP purge valve issue, would be worth going to replace sooner rather than later

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