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#1 |
Registered User
Join Date: Jul 2008
Location: Concord, CA
Posts: 194
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Fuel gauge
My fuel gauge just stopped working. I did a visual check of the fuses, everything looks OK. Where do I look next?
'77 stepside, big block, dual tanks. Thank you, Dan |
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#2 |
Robert Olson Transport
![]() Join Date: Oct 2002
Location: recent transplant to NC USA
Posts: 20,287
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Re: Fuel gauge
is there any change with switching the tanks?
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Bob 1951 International running on a squarebody chassis "If a man's worth is judged by the people he associates himself with, then i am the richest man in the world knowing some of the fine people of this board" http://67-72chevytrucks.com/vboard/a...t.php?f=25&a=9 (you can review the site rules here!) PM Me for your vehicle/parts hauling needs in the North East US or see my Facebook page Robert Olson Transport Live each day to the fullest.. you never know when fate is going to pull the rug out from under you... I hate cancer!! |
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#3 |
Account Suspended
Join Date: Jun 2009
Location: kansas city Ks
Posts: 1,970
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Re: Fuel gauge
I'm looking for a similar answer, mine is readiing a 1/4tank low. so is it the guage or the fuse or the sending unit?
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#4 |
Registered User
Join Date: Jul 2008
Location: Concord, CA
Posts: 194
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Re: Fuel gauge
No, the gauge does not move for either tank. It is pinned all the way to the right (past full).
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#5 |
Registered User
Join Date: Aug 2009
Location: Hamilton, Ontario
Posts: 41
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Re: Fuel gauge
having a similar problem with mine. Replaced the gauge with another I had, same thing. I've not gotten any further into the problem.
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#6 |
Registered User
Join Date: Jul 2008
Location: Ault, Colorado
Posts: 862
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Re: Fuel gauge
Yo! Wow! Just posted this info in pokethesmot's post. Pegged beyond full is an indication of an open circuit, and is usually attributed to a bad ground on the inner frame. Could be a bad sender if you've not replaced it already, or could be a damaged pink (or light brown) sender wire between the gauge and sender.
Todd.
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'78 3/4 ton 4x4 custom "Todd-built" FRANKENTRUCK! Last edited by asphaltburner; 08-21-2009 at 05:57 PM. |
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#7 |
Registered User
Join Date: Jul 2008
Location: Concord, CA
Posts: 194
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Re: Fuel gauge
Todd,
Thank you for the info. I will check those issues ASAP. Dan |
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#8 | |
Still plays with trucks
Join Date: Jul 2009
Location: Spokane, WA
Posts: 3,556
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Re: Fuel gauge
Quote:
Turned out the float had a leak in it and was partially submerged in fuel. Check the float in the tank. |
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#9 |
Registered User
Join Date: Dec 2007
Location: Palmer, Alaska
Posts: 13,821
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Re: Fuel gauge
a leaky float will give you low readings.....as Todd stated, pegged to full is an open circuit, and since both tanks show the same look at what is in common for both tanks...which is also what Todd had said
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#10 |
Registered User
Join Date: Jul 2008
Location: Ault, Colorado
Posts: 862
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Re: Fuel gauge
Yo! Dudes!
The new senders that I bought have solid floats so they'll never leak, so replacing old senders (if inaccurate or malfunctioning) would sure be a plus. LMC and Classic Industries have them. They ARE, however, $70 each. Todd.
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'78 3/4 ton 4x4 custom "Todd-built" FRANKENTRUCK! |
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#11 |
Registered User
Join Date: Dec 2007
Location: Palmer, Alaska
Posts: 13,821
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Re: Fuel gauge
Soild?
what is it made of?
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#12 |
Registered User
Join Date: Jul 2008
Location: Ault, Colorado
Posts: 862
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Re: Fuel gauge
Yo! Some kinda very dense material, shaped like a roll. Doesn't seem porous,...cool, huh?
Todd.
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'78 3/4 ton 4x4 custom "Todd-built" FRANKENTRUCK! |
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#13 |
Registered User
Join Date: Dec 2007
Location: Palmer, Alaska
Posts: 13,821
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Re: Fuel gauge
yeah, that is wild
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#14 |
Registered User
Join Date: Jul 2008
Location: Ault, Colorado
Posts: 862
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Re: Fuel gauge
Yo! joe231!
I just LOVE applying new technology to my 30+ year old vehicles!! Todd.
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'78 3/4 ton 4x4 custom "Todd-built" FRANKENTRUCK! |
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#15 |
Registered User
Join Date: Dec 2007
Location: Palmer, Alaska
Posts: 13,821
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Re: Fuel gauge
Heck yeah!!
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#16 |
Registered User
Join Date: Jul 2008
Location: Concord, CA
Posts: 194
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Re: Fuel gauge
I found it. A spliced section of wire was missing running along the frame between the passenger side tank and the firewall.
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#17 |
Still plays with trucks
Join Date: Jul 2009
Location: Spokane, WA
Posts: 3,556
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Re: Fuel gauge
Glad to hear it was something easy.
Dropping the tank sucks especially if it has much fuel in it. I just helped a friend change the in tank pump on his late 90's Chevy van. It has a 100 gallon tank and we could only get 50 gallons out of it with all the gas cans in the neighborhood so we still had probably 35 gallons to deal with. Good thing I had a tranny jack. |
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#18 |
Registered User
Join Date: Jul 2008
Location: Ault, Colorado
Posts: 862
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Re: Fuel gauge
Yo! Far out!
Todd.
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'78 3/4 ton 4x4 custom "Todd-built" FRANKENTRUCK! |
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#19 |
Registered User
Join Date: Oct 2009
Location: Brighton, CO
Posts: 8
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Re: Fuel gauge
Mine did the same exact thing, read a bit over a 1/4 a tank to empty through the full range sweep. I tried a new sender it did the same so I know it's not the float. The wiring checked out but have'nt checked the gauge. Anyone know how to test the gauge? In or out of the truck?
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#20 |
Registered User
![]() Join Date: Feb 2003
Location: Mulvane, Ks.
Posts: 754
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Re: Fuel gauge
Hey guys, along the same lines, when I start out with a full tank, the gauge works fine; however, when the gauge drops to about 3/8 of a tank full, it will start fluttering real bad. Any possibilities?
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#21 |
Still plays with trucks
Join Date: Jul 2009
Location: Spokane, WA
Posts: 3,556
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Re: Fuel gauge
Sounds like a bad spot in the float level rheostat.
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#22 |
78K & 79C Jimmys
Join Date: Nov 2009
Location: Ottawa Ont CANADA
Posts: 7,901
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Re: Fuel gauge
an open/cut sending wire will max out over full
a grounded wire will go empty a flutter might need a ground in the cluster may want to try adding a ground behind it..... there they all go to one
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#23 |
Registered User
Join Date: Jun 2004
Location: Los Angeles
Posts: 277
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Re: Fuel gauge
I just went through this...my fuel gauge was stuck at 1/4 and didnt move at all. The culprit was the wire that goes from sending unit to dash.
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#24 | |
Registered User
Join Date: Sep 2010
Location: Lake Tahoe, Nevada
Posts: 755
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Re: Fuel gauge
Quote:
You can accomplish this by pulling the actual wire off the sending unit and connect a resistance to ground, and this will not only test the gauge, but also all the wiring associated with all of it. Variable resistors (also called Rheostats or Potentiometers, or pots for short) are only a few bucks from Radio Shack, the hardest part is making sure you're showing the gauge a realistic resistance. Keeping within 0-90 ohms is going to be difficult with a potentiometer that ranges from 0-100,000 ohms. If that's your choice, you might actually be better off buying a selection of fixed resistors and using them. Let me know if you want more help, not only am I an electrical engineer, I just recently fixed a similar issue on my 79 squarebody. I had to replace the sending unit, along with most of the wiring all the way to the dash (luckily, my gauge was still functional). |
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#25 |
Registered User
Join Date: Oct 2009
Location: Brighton, CO
Posts: 8
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Re: Fuel gauge
Resistance makes sense, both my new and old rheostats do the same thing. The full sweep ranges from empty to just above a quarter tank, but it still is a full sweep (i.e. the gauge isn't stuck at a quarter a tank until the tank reaches a quarter, it sweeps the entire capacity of the tank). Wouldn't that mean added resistance in the gauge or printed circuit?
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