CODE P051B on Stored Fiesta

[BlackdiamondJB]

Hello, My car is running poorly with bad gas mileage and throwing codes:

Some initial information: My Fiesta was driven about 500 miles in total last year (October 2020 - December 2021) I filled up on gas twice during this time (only to halfway mark both times). Recently I turned on the car and got this code (P051B) and after checking online, a possible issue could be old gas sitting in the tank. The car also runs poorly with noticeably less power as well as very poor gas mileage
I am also currently in the process of changing oil, other fluids, and other basic maintenance.

Should I add additives to the fuel to continue storing? or flush the entire fuel system (not sure how that's done lol).

If there is any other advice for storing the car as well, I am all ears.

 

[XR650R]

How much fuel is in it now?

 

[haste]

Where is it being stored? Temperature controlled environment or just outside?

 

[BlackdiamondJB]

How much fuel is in it now?

1/2 full, recently put fuel in it about 2 weeks ago because I drove it approx. 30 miles.

 

[BlackdiamondJB]

Where is it being stored? Temperature controlled environment or just outside?

It’s in a garage. It’s not temp controlled but is an insulated garage.

 

[XR650R]

https://autoservicecosts.com/obd2-codes/p051b/
Check that the oil isn't overfilled.
Drive it a while, if you can. Get the fuel down as far as you dare, then top it off with premium. If it's the fuel, it should run better then. Put Sta-bil or something similar in it if it's going to be sitting. Gasoline doesn't stay fresh for more than a month or so. Sta-bil will help keep it OK for 3 months or so.

 

[haste]

https://autoservicecosts.com/obd2-codes/p051b/
Check that the oil isn't overfilled.
Drive it a while, if you can. Get the fuel down as far as you dare, then top it off with premium. If it's the fuel, it should run better then. Put Sta-bil or something similar in it if it's going to be sitting. Gasoline doesn't stay fresh for more than a month or so. Sta-bil will help keep it OK for 3 months or so.

Was going to suggest the same thing. Run it low, fill it, run it low again and fill it fresh. It may even be advantageous to add a water remover to the first fill-up. DEFINITELY add sta-bil to the "storage" tank.

 

[Snrub]

Generally speaking you don't want to have significantly old gas in the tank. Year old gas is a problem. To give you context my lawn mower doesn't recommend gas older than a month. I suspect about 3 is months is the maximum you want to do without stabilizer. If it's mostly 2 week old gas in the tank you might be okay. If you're going to be using the car sparingly, use fuel stabilizer and keep the levels lower, that way when you fuel up you're diluting the old fuel more. There's an alternative school of thought which suggests less air in the tank means less moisture can be absorbed, but it's less practical.

Edit: there are fuel syphoning tools which can cost as little as $5. I haven't done this on a capless system, but do a quick Google and there is a simple trick. https://www.harborfreight.com/fluid-siphon-pump-62613.html

 

[BlackdiamondJB]

Generally speaking you don't want to have significantly old gas in the tank. Year old gas is a problem. To give you context my lawn mower doesn't recommend gas older than a month. I suspect about 3 is months is the maximum you want to do without stabilizer. If it's mostly 2 week old gas in the tank you might be okay. If you're going to be using the car sparingly, use fuel stabilizer and keep the levels lower, that way when you fuel up you're diluting the old fuel more. There's an alternative school of thought which suggests less air in the tank means less moisture can be absorbed, but it's less practical.

Edit: there are fuel syphoning tools which can cost as little as $5. I haven't done this on a capless system, but do a quick Google and there is a simple trick. https://www.harborfreight.com/fluid-siphon-pump-62613.html

Appreciate the link! I will definitely try that because it has a decent amount of fuel in it and I ran into a few more problems that I should fix before driving the car.