fuel gage slams to full!

[claybill]

what does it mean when your gage slams to the full mark whenever you turn on the key?

i remember reading this awhile back..and now it is happening to me.

looked up archives and cant find the thread.( but found lots of other good info!)

i have a 41 ply coupe..360 v8 auto. aftermkt gage unit on bracket under dash.

also a gage n dash cluster, not hooked up, dont kow..

bill

[greg g]

Look for an unintended ground. I had the defroster duct come off the diffueser. The wire reinforcement of the duct grounded the gauge giving me a false full rating. That was on the stock gauge though, not certain about the cause on an aftermarket deal.

[P-12 Tommy]

It does sound like a grounding issue.

Tom

[40plyrod]

Make sure the tanks not full of fuel first:D Last fall when I took my pick up off the road for the winter I rebuilt the carb and rewired it. After rewiring it I started checking the circuits one at a time. The lights worked fine so did the signals so I turned on the key to check the gauges, guess what fuel gauge spikes hard to full. Well I couldn't fine anything wrong with the gauge(I thought I might have broken the contact inside when I removed the wire) The wiring looked good right back to the sender so I decided to check the sender. It was when I removed the sender that it hit me that I had fueled the truck right full before taking it off the road:rolleyes:

[Jim Yergin]

I had an old Mustang once where the gauge just went to full even though I didn't have a full tank. Turned out the float on the sending unit arm had fallen off so the arm just stayed up and the gauge read full.

Jim Yergin

[claybill]

thanks all.

it sounds more 'electrical', as the needle literally slams against the full peg.

and i have 1/2 tank of fuel....however, gotta look at everything, i have made that mistake a few times!!!

will the snow ever stop...and now, will the rain ever stop! mud mud mud.

claybill

[W.F. Brown- III]

Could the same scenario (unintended ground) apply if the needle slams to "E"? My fuel gage was working (well "most of the time") until today. I was working under the dash and hit something on or near the contacts of the fuel gage and the needle went over to empty and did not budge (well, it moved just a bit one time, then nothing).

Could I have shorted something out or caused an unintended ground some way? Or did I just kill the dang thing?

[claybill]

shell....couldnt find an electrical short in dash....i will take out the tank unit another time. i guess someone dug up the old thread.

bill