manystangs

Just an FYI. Yesterday on my way to work my fuel gauge was working fine. When I went to lunch it was on E and I know I had a half tank. I always get fuel from one of two places, so I did not think that was the problem. I know there has been talk of Sulfur causing the fuel gauge to malfunction so I filled back up just to double check and still no go. When I got home I hooked up my Xcal2 and checked for codes, none found. So I reflashed to stock and the gauge worked immediately. Reflashed my tune and it still works fine! I quess it was a glitch, who knows, but it works fine now! I hope this helps.
Michael

Faber

mine has been working intermittently as well. i recently had a gauge cluster issue where it was throwing fuel sender codes. ford said the issue was caused by my mp3 player, and removed it. Now the gauge quits working once in a while also....wierd.

MustangRetribution

Id go to a diffrent dealership because they are feeding you some , there was a tsb for replacing the fuel sending units, I haven needed to do it myself buy my buddy has.

theedge67

If you suspect any sulfur buildup, try a bottle of Techron fuel additive at your next fillup.

manystangs

I don't really suspect the sulphur buildup because the reflash fixed it, but who knows? Thanks for the tip, but I already do that. Thanks.
Michael

kevinb120

Faber

replaced the senders and pump (or said they did) and the problem remains. erratic fuel gauge sometimes shows correct, but most of the time shows empty. the idiot light does come on when the tank is close to empty though.

manystangs

I think mine is instrument cluster related. When gauges are returning to rest, you can see the fuel gauge jumping like it has something stuck in the mechanism. I spoke with the dealer and they agreed and they have to order it. I just have not been in a huge hurry do to the message center working and I never run it down too close to empty.

StangMahn

I drive two vehicles on a regular basis on which the fuel guages dont work, I just know the mileage, and fuel up then.

fastduo

I have had two pumps replaced so far. The first one for a failed fuel gauge and the second for the Hessitation TSB. During normal driving the gauge operates normally but at the track events, below 1/2 shows empty after a few high speed road coarse corners, it can not keep up and stays on E. I just keep going until the fuel light stays on as that seems to remain accurate, then I come in and gas up.

davids2toys

My gas gauge has worked perfectly for 2 years now, all of a sudden I ran out of gas, the gauge still said 1/3 tank, and NO light, also, only 280 miles, I can usually go around 330!
After I filled it up, I put on 100 miles, and it still says FULL!!!
When I shut the key off it goes to empty, key on, it goes to full .
Any ideas??

shaun_beauchamp

For everyone except David,

The fuel sensor doesn't like excessive lateral movement (i.e. track days). I took the mechanic from Ewald's Hartford Ford Lincoln Mercury on a spirited ride and showed him. I can slide the car through the dealer parking lot and make it happen (fun as hell, showroom full of people pressed against the glass). If I drive "normal" to the station and fill it up, it seems to reset at a full tank (which is sometimes less than 1 gallon of fuel added). So, drive "normal" or fill up more often, or use the dummy light, your option, as "fixing" the problem with a new pump/sending unit is only going to solve the TSB for the fuel pump.

OK, David, sounds like you have some RESISTANCE issue. The signal from the tank is most likely analog and you have an "all or nothing" issue. I suggest you have a short in a wire. Have them "fix" it under normal means and if that doesn't work, have them check the resistance in the wiring with a Digital Multi-Meter. If the mechanic doesn't have one in his box, find another mechanic to troubleshoot electronics as anyone with a decent meter will most likely fry something.

Later,

Shaun

davids2toys

Oh, I dont think this sounds good at all, I am put away for the winter, Probably go back on the road end of March. I was going to take it to the dealer then, I do dread it, but now I am getting a P.S. noise, so I guess I am not going to have a choice.

I am under warranty until June! I am hoping I did not damage the fuel pump by trying to start my car repeatedly on the side of the road, I also unloaded my tune and loaded the stock tune, that means the fuel pump was on with the key, with no fuel going thru it to cool it. Is my thinking correct here?

Jnel

You should be ok. I believe the PCM needs to see oil pressure, among other sensors to keep voltage going to pump, it runs briefly on cranking to bring pressure up.

theedge67

Correct, the pump will only cycle for a second before it shuts off. If there is no fuel to pump, it should not even cycle at all. For the fuel gauge, you could try a tank with some Techron additive. You can find it at any auto parts store for around $6 a bottle. It seems to clean off any sulfur or gunk on the sending unit in the tank.

shaun_beauchamp

The TSB provides you with a new fuel pump, so no worries David.

As for this Techron, any crazy exhaust emissions like seafoam?

theedge67

No, it is just a fuel additive. It's a solvent I think. It is a concentrate of the fuel additive package in Chevron's gas, which is what the Big 3 use when they run SAE horsepower tests, and EPA emissions tests on their engines. Chevron doesn't sell any gas around Detroit either, the auto manufacturers truck in the Chevron from Kentucky!! It must be good stuff. Plus Ford recommends it if you have fuel buildup problems. I think it's the only additive Ford gives the blessing to.

shaun_beauchamp

I believe the MotorCraft Factory Semi-Synthetic for the Mustangs is a Chevron product also. Seems there is a positive collaboration between the two. My gas cap says Ford Recommends BP. I buy Mobil and BP for both Mustangs and don't seem to have an issue.

Thanks,

Shaun

YourCar

It's possible that the following part may be malfunctioning:

MOTORCRAFT. SW6868. Instrument Cluster Voltage Regulator Switch

Its a switch near the gear stick. It has 3 buttons on it [ traction control, emergancy hazzord linghts and trunk release]. This is my second time I'm changing it. The first time the Hazzard light kept randomly flashing while parked

On my car I also had issue with turning off/on traction control and it was also malfunction. Try toggling the traction control and if its also malfunctioning, then you know its that switch. That's how I came to know that the switch was the problem. It only cost $38 from RockAuto.com

I hope this helps.