john hess Posted September 28, 2020 Share Posted September 28, 2020 Whats going on here ?.... 53 pontiac fuel guage reads full when key off. Start engine, reads proper... Added fuel... Restarted engine and guage shows additional fuel... Stop engine, guage goes to full.. Key on registers ok.... History... Tank removed and cleaned. New sending unit installed. Tank has not been completely full for some time as restoration continues, so not much sloshing of gas in tank... Probably 2 years... Any ideas on this ? Thanks in advance, John Link to comment Share on other sites More sharing options...
JACK M Posted September 28, 2020 Share Posted September 28, 2020 Sounds like its working unless I am reading this wrong. Registers properly when the key is on or engine running. Gauge parks itself when the key is off. 1 Link to comment Share on other sites More sharing options...
john hess Posted September 28, 2020 Author Share Posted September 28, 2020 Just thought it should go to empty when key off.... Not full..... Oh well, as long as it registers proper while running, I guess no worries... Thanks for your reply Jack M Link to comment Share on other sites More sharing options...
john hess Posted September 28, 2020 Author Share Posted September 28, 2020 Tank initially has 2 gallons in it. Reads 1/8 full... Ok, then key off.. reads full... ?? Add 5 gallons, key on, reads about 1/3. .. key off, goes to full... Key back on, reads 1/3..... Not even drinkin today !!! Just doesnt figure in my brain... No other car or truck I ever had, did this..... Guess I do need a beer, then move on..... John 1 Link to comment Share on other sites More sharing options...
MCHinson Posted September 28, 2020 Share Posted September 28, 2020 I have never heard of any car fuel gauge set up to operate like that but I know nothing about 1953 Pontiacs. Does the sending unit have 1 or 2 wires? Perhaps if it has two wires, if you switched the wires, it would go to empty when off like I feel fairly confident it should do? Link to comment Share on other sites More sharing options...
john hess Posted September 28, 2020 Author Share Posted September 28, 2020 One wire only on sending unit... Grounded through tank straps to frame.... Also have jumper from sending unit screw to frame... Confused, l am..... Link to comment Share on other sites More sharing options...
maok Posted September 28, 2020 Share Posted September 28, 2020 The wires one the gauge reversed? Link to comment Share on other sites More sharing options...
MCHinson Posted September 28, 2020 Share Posted September 28, 2020 My initial thought would be to double check to make sure that you don't have the ground wire hooked to the gauge wire and the sending unit wire grounded. That is the only way that I can imagine the gauge operating how you are describing. Link to comment Share on other sites More sharing options...
Ben Bruce aka First Born Posted September 29, 2020 Share Posted September 29, 2020 14 hours ago, john hess said: One wire only on sending unit... Grounded through tank straps to frame.... Also have jumper from sending unit screw to frame... Confused, l am..... I would not feel the ground is adequate. I ground mine with a 12ga wire from a bolt on the sending unit flange to the frame. Ben Link to comment Share on other sites More sharing options...
john hess Posted September 29, 2020 Author Share Posted September 29, 2020 I will run a ground wire direct to battery... ThinkIng about this, I should know better.. most electrical issues are ground related. Since the car was separated from frame, epoxy undercoated, frame painted, new rubber body mounts, there are multiple points of failure here.. Lots of time to think about this while driving truck.(my day job)... Thanks to all responses so far... I will post results tonight.... By the way, Im writing rhis as truck is being unloaded !!! .... Jihn 2 Link to comment Share on other sites More sharing options...
john hess Posted September 30, 2020 Author Share Posted September 30, 2020 Well, late day... No electrical work tonight... Dark and raining here in SE PA.... Tomorrow is another day.!! Link to comment Share on other sites More sharing options...
john hess Posted October 3, 2020 Author Share Posted October 3, 2020 Thanks all who commented.... Problem solved.... Guage works proper now... Bolt holes painted shut on cluster mount when I painted dash... Only holes I forgot to chase before mounting... All is well... John 5 Link to comment Share on other sites More sharing options...
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