Gas gauge problem
 

Whats up all. I need your help with an anoying problem. Once a year for a whole week, my gas gauge descides to not work at all. As a matter of fact, the needle goes the opposite way(maybe shorting) when I turn on the ignition. Again,this happens to me for about a week and then it'll work again perfectly for another year. I've owned the car for 7 years and its done this for 5. I have changed my sending unit and checked all the rear wiring to no avail. This drives me nuts! I have to keep the tank full cause I don't know my mpg's. Can anyone help? Thanks.

If it goes up way past full it is shorting out. Mine did this. The float pivots on a contact that touches a little "circuit board" of copper contacts. The copper contacts on mine were worn through.

Thanks for the info but the needle goes all the way down and stays there when I turn on the ignition.

exgmguy, mine does what you explained, but only on a cold startup, then it goes back to normal, should i be ready for it to short or fail?

------------------
90 lx coupe: Mac cold air fenderwell, accel supercoil,advncd ignition,3-core radiatr, FMS alum D/S, Black magic fan, 3.27grs, 3chbr flows.
Best time: 13.9116(on 225/60/15 firehawks)
Best mph: 98.17
Best 60': 1.9607

next mods: subframes, mac h-pipe

I know there is a factory flaw in some years of fox bodies that makes one of the guages, temp or fuel, act funny when you turn on the driving lights. And no, I don't mean the voltage guage for any of you wiseguys. lol.
At least I thought it was funny.

Just me
91'lx, 302 block, crank pulley, no smog, short belt, Wolverine 1087 cam, 15 deg timing, TFS TW heads, motorsport 1.6 3/8 stud RR, ARP studs, TFS chrome hardened push rods, 24lb inj, BBK 255lph fuel pump, Areomotive billet adj FPR, Performer RPM intake(ported to 75mm), 1" spacer, Motorsport polished tall valve covers(love em), Pro-M 77, Acufab 75mm TB, Ford idle air bypass valve, K&N conical, MSD 6AL and coil, 9mm MS cables, NGK bkr5e 11 plugs@55, motorsport 3 core radiator,160 thermostat, Hurst short throw, motorsport 410 gears, aluminum drive shaft, Kenny brown Subs, Mac 1 3/4"Long tube, custom 3"off road xpipe, 2 chamber Flow Masters, 3 1/2" tailpipes HAL tubular K-member, KYB struts and shocks, Eibach springs, Steeda 2.5" Cowl, Steeda rear wing, black Dupont centari acrylic enamel paint. Going for an electric fan setup with a blower.

justme, My gauge does the exact same thing yours does. I reset the trip odometer to zero at every fill-up and when it reaches 200 miles or so I get gas again. This method is very accurate for me.
I was told it was either the gauge itself or the sending unit.
Exgmguy, is the sending unit in the tank?



------------------
'82 GT 351W C-4,BBK headers,Carter 625 carb,Comp.Cam,Flowmaster exhaust.
1988 GT...T-5,bone stock

Yeah the sending unit is in the tank I tried to get one from Ford and they said they could only sell the sending unit with the fuel pump attached as one assembly for something like $150. but other people have told me that their dealership sold the pump and sending unit seperately... you'll have to check your particular dealership to see. If not, Texas Mustang sells the sending unit for $80

------------------
1988 mustang GT (AOD)(speed density)
full exhaust, underdrives, K&N 3:55's
BEST ET: 14.05 99.56

I bought my first 5.0 about 11 years ago. It was an 87 with like 79k on it. I spent all the money I had extra to buy it and was so happy that it had a full tank. Got about 20 miles into my cruising around that night and the low fuel dummy light came on and the needle dropped. My gauge only worked when the dummy light was on and that was it. Just another scenario with a funny story.