Need help, fuel concerns 2020 GT

[Creamsicle5.0]

Sorry if I’m posting in the wrong section, Im new to the forums!

Here’s my problem. I have a 2020 Mustang GT. My problem started friday night. I topped my tank off, drove about 40-50 minutes, and when I came to a stop and shut my car off, it sat about 5 minutes and wouldn’t start again. It would fire over and immediately stall after firing, it wouldn’t stay running. After awhile, it won’t fire over at all, just cranks. What’s particularly weird to me is every once in awhile, it’ll fire over and run fine, after amount 3 hours of trying that night that’s how I was able to get it home (about a 15 minute drive with a few stop lights). The fuel pumps, both high pressure and low pressure pumps seem to be operating fine.

Attached files show the error messages that FordPass gave me. I checked fuses and plenty of wires and connections, they all seem to be good. I’ve drawn blank on what to do before I dumped tons of money into something that may not be the issue. I’m out of warranty, the car is modified.

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[Linkster1666]

Did you 'Top Off' the tank when you filled up? Did you give it more fuel AFTER the pump turned off? A couple extra squeezes, maybe?

 

[Creamsicle5.0]

Did you 'Top Off' the tank when you filled up? Did you give it more fuel AFTER the pump turned off? A couple extra squeezes, maybe?

Yes, when I fill up I always wait a few seconds after the pump clicks and click it one more time.

 

[ORRadtech]

Do you have a decent scan tool?
How old is the battery?
Topping off the tank is a bad, bad idea. It can cause all kinds of codes especially emissions.
Modern cars are extremely interconnected. If the computer detects code it deems serious enough it can start setting other faults. Finding the root cause can clear most others.

 

[Creamsicle5.0]

Do you have a decent scan tool?
How old is the battery?
Topping off the tank is a bad, bad idea. It can cause all kinds of codes especially emissions.
Modern cars are extremely interconnected. If the computer detects code it deems serious enough it can start setting other faults. Finding the root cause can clear most others.

l
I don’t have a code reader, I thought about picking one up this evening. I work for a Ford dealer in their sales department, but it would still cost me a few hundred to get it towed from my house to our garage as I live a bit away. The battery shouldn’t be that old, I’ll check the sticker when I get home this evening. I did check the battery voltage and it seems to be healthy

 

[Linkster1666]

You shouldn't ever do that with these cars. They, and most modern cars have Evap equipment. They take the fumes from the tank and fuel system and add them back into the fuel burning process.

What I think has happened is you over filled and got liquid in the evap system, this is a bad thing.

You may get lucky and the canisters and the other equipment are not 'water logged' with fuel and you can get away with NOT replacing the Evap System parts.

Take to your mechanic for diagnoses. I maybe wrong but that is my opinion. Good luck.

 

[Creamsicle5.0]

You shouldn't ever do that with these cars. They, and most modern cars have Evap equipment. They take the fumes from the tank and fuel system and add them back into the fuel burning process.

What I think has happened is you over filled and got liquid in the evap system, this is a bad thing.

You may get lucky and the canisters and the other equipment are not 'water logged' with fuel and you can get away with NOT replacing the Evap System parts.

Take to your mechanic for diagnoses. I maybe wrong but that is my opinion. Good luck.

Appreciate the help! Is there anyway to diagnose at home? I do 95% of work on my vehicles, I’d like to save a trip on the tow truck and hundreds in diag if I can.

 

[K4fxd]

If it is fuel in the evap system it will clear itself after awhile.

Never over fill these cars. If it starts now take it for a drive. I wouldn't shut it off till I got home.

IIRC these purge the evap on start up so if your tank is below the vent starting and and letting it warm up then shutting it off and re-starting might clear it quicker than just driving. I don't know Fords algorithm while driving.

If it's not the evap system all faults point to an electrical problem. My guess would be with the pump controller.

I had some evap issues, MIL light on and I found a mouse ate through the wiring under the rear seat.

 

[Creamsicle5.0]

If it is fuel in the evap system it will clear itself after awhile.

Never over fill these cars. If it starts now take it for a drive. I wouldn't shut it off till I got home.

IIRC these purge the evap on start up so if your tank is below the vent starting and and letting it warm up then shutting it off and re-starting might clear it quicker than just driving. I don't know Fords algorithm while driving.

If it's not the evap system all faults point to an electrical problem. My guess would be with the pump controller.

I had some evap issues, MIL light on and I found a mouse ate through the wiring under the rear seat.

The issue right now is that I’m having trouble getting it to start and stay running. It fires over and stalls immediately and I can’t tap the gas pedal to keep it running. All the wires I checked seemed to be fine, I’ll recheck all the wiring tonight. Another issue is that when it does actually start and run fine, it won’t start again after I shut it off.

 

[Linkster1666]

Appreciate the help! Is there anyway to diagnose at home? I do 95% of work on my vehicles, I’d like to save a trip on the tow truck and hundreds in diag if I can.

A code reader is gonna help a TON if you are working on cars yourself. Start there. The Forum should help you find one, I went the cheap route 75-100 bucks, up to you.

 

[Creamsicle5.0]

A code reader is gonna help a TON if you are working on cars yourself. Start there. The Forum should help you find one, I went the cheap route 75-100 bucks, up to you.

For sure getting one after work, my local autozone has multiple kinds. I owned a BMW before my F150 and 2 mustangs, the code reader I have is BMW specific which is why I don’t already have one.

 

[ORRadtech]

Cheap code readers will read the codes just fine BUT
If you plan on working on your own cars a bidirectional scan tool is worth the money. They can run from a couple hundred dollars to several thousand. Good ones for a serious diy guy are $600 - $1k. The things they allow you to test and do make them worth the investment. Look into Autel for examples of what they can do.

What is your definition of a healthy battery voltage?
FWI, a fully charged battery is the first step when diagnosing anything on a modern car.

 

[Creamsicle5.0]

Cheap code readers will read the codes just fine BUT
If you plan on working on your own cars a bidirectional scan tool is worth the money. They can run from a couple hundred dollars to several thousand. Good ones for a serious diy guy are $600 - $1k. The things they allow you to test and do make them worth the investment. Look into Autel for examples of what they can do.

What is your definition of a healthy battery voltage?
FWI, a fully charged battery is the first step when diagnosing anything on a modern car.

Voltage read 12.2 when I checked the voltage.
And I do plan on investing in a high quality scan tool, for now I just need to get my car on the road

 

[Qcman17]

If the cars a 2020 would it not be covered under warranty still? And I would assume warranty would cover towing the car too?

 

[ORRadtech]

12.2 volts may not be as healthy as you assume.
Charge it fully and possibly have it load tested before proceeding.

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