I need help! Low Fuel light on right after fill?

[evil281]

I have a 99 mustang gt and a couple months ago the low fuel light would come on just very randomly sometimes even the day after a fill up so i know it wasnt right. well anyway it hasnt done this in probly 5 months but yesturday I filled up a full tank and this morning on my way to work the low fuel light came on again, Id really like to fix this for good, any suggestions as to what it is?

[BurnTire]

It is probably related to the float, sending unit in the tank and/or the wiring.

Does the actual light that comes on say low fuel?

I am just curious if your year has a check fuel cap light?

[evil281]

The needle points to empty and the "low fuel" light comes on

[BurnTire]

The needle points to empty and the "low fuel" light comes on

Sounds like the float/sending unit which is in the tank.

Also do you have the ability to scan the computer for codes?

[evil281]

I think I can scan with my diablo tuner, but will a code come up if the check engine light is not on?

[YellowGT5.0]

Hey man we carry this stuff that cleans out the fuel system and my friend had the same problem with his car and he put this stuff in his fuel and his sending unit worked right after. But if it does not work then you need to drop the tank and either clean the sending unit or get a new one. I have dropped so many tanks over the past month so i'd be happy to help you out if thats what your going to do.

[El Jefe]

Mine did that 1 time. I had just filled up and was going through the carwash. Gauge read empty and my light came on. Turned the car off and then back on and never had the problem again.

[evil281]

Thanks guys we will see what happens then and if i need ur help ill give u a buzz and we can change that tank out

[BurnTire]

I think I can scan with my diablo tuner, but will a code come up if the check engine light is not on?

Yes there are hard and soft codes. Some will not trip the check engine light, but will be stored.


Thanks guys we will see what happens then and if i need ur help ill give u a buzz and we can change that tank out

No need for a new tank, just the sending unit and possibly the float.
It is hard to tell what the issue is until you get in there and look.

[IMSHAKN]

I've had it happen once before last summer. The problem is pretty common on some of ford's other lines such as the explorer. The 'fix' that the dealerships recommend is putting in a bottle of the fuel additives every 5k or so.

[BurnTire]

I've had it happen once before last summer. The problem is pretty common on some of ford's other lines such as the explorer. The 'fix' that the dealerships recommend is putting in a bottle of the fuel additives every 5k or so.

Maybe there is some gunk on the unit. Sounds like the float is sticking in the down position.

[IMSHAKN]

basically that is the theory as to why it causes problems on some of the vehicles and that the additive will clean things up so they work properly. Damn things.

[evil281]

Good news at least for now, I was driving home from work today and it started reading correct again, we will see if it lasts long again, thanks for the help guys.