Newb2ford

Hey guys, I just had a local alarm shop install a viper alarm in my 2011 mustang gt 5.0. When I went to pick it up I started the vehicle and the gas tank gage showed empty and the info reading said I had 0 miles before empty. I swear when I dropped it off it had just over a 1/4 tank left. Anyways, I first suspected that they went for a joy ride. When I went to chevron to fill up however, it only let me fill a little over 8 gallons. When I started the car again the tank read full. I believe this car holds about 16 gallons. I called the alarm shop to ask if they had to unhook the battery during installation and they said no. Anyways, I thought it was weird that the gage read empty and then full after only filling up 8 gallons. It sounds like the gage reading was incorrect for some reason. I can't figure out what happened. Any ideas? Thanks.

LostBoyz

Sounds like a saddle bag fuel tank issue. you are only filling half the tank

parchisi

Yup, sounds to me like the saddlebag fuel tank issue. I think there's a TSB out on it. Take it to the dealership and keep in mind that the car will only be running off of a half tank.

Newb2ford

Thanks for the info guys. I really appreciate it. I plan on taking it to the dealership early next week. Now I have return the the stock tune and CAI. Bummer.

JIM5.0

No you don't. They cannot deny you warranty work on your tank even if you supercharge you engine. They might give you S*** for having a supercharger, CAI, and tune, but they ca\\still cannot deny warranty work on the tank. The reason why is because there is no way i hell a CAI and tune can cause your fuel tank to F*** up.

Now, if you engine blow up and it is because your tune was the cause, then yes, they could deny you warranty service on the engine. But again, they still cannot deny you warranty work on the tank even if your engine is dead.

musty ruffler

well, i've got an '06 v6 but have seen this identical behavior when battery was completely drained due to an alternator malfunction. once the alt issue was resolved, driving far enough to charge the battery a bit resolved the issue.

did the car start up easily when you picked it up from the stereo install?

Nuke

I know that the 05-10's can have an issue if the tank is filled with the ignition not in the off position but that doesn't sound like your situation. Keep us posted.

Oh, and I concur that you don't need to return to stock for this. I wish folks would grow some stones and quit wussing out because of dealership intimidation.

Newb2ford

Yep. Anyways, I found out that there's a guy I went to high school with that works in Ford's parts department. He set up my appointment for me and reassured me that the service dept. wouldn't hassle me about the mods on my car. He also told me the tech working on the car got on his case because he didn't tell me not to bring the car in with a full tank of gas. I guess some of it spilled but not on the upholstery. I left my window open for a few hours and the gasoline smell isn't there anymore. With these newer mustang models the fuel pump is under the rear seat.

Hopefully the fuel pump module replacement fixes the issue. Of course it didn't cost anything because it was a TSB issue and obviously still under warranty(390 miles). I'll update you guys if it doesn't and thanks again for the prompt replies.