MoparFins

Please login or register.

Login with username, password and session length
Advanced search  

News:

We changed servers, which is good, and lost all passwords, which is bad. See above.

Pages: [1]   Go Down

Author Topic: fuel gauge  (Read 556 times)

BLACK 60

  • Newbie
  • *
  • Karma: +0/-0
  • Posts: 10
    • View Profile
fuel gauge
« on: May 02, 2009, 11:41:43 AM »

here is my question. I have a fuel gauge that stays on full all the time. As if it were grounded. The car is a 60 New yorker. The wiring looks very good, could it possibly be the sending unit in the tank. Any help would be appreciated.
Logged

Steve

  • Administrator
  • Hero Member
  • *****
  • Karma: +1/-0
  • Posts: 8653
    • View Profile
fuel gauge
« Reply #1 on: May 02, 2009, 05:17:54 PM »

It could be 20 things.
 
Here I wrote this a few years ago.  It's on the mopar fins web site
 
http://www.moparfins.com/Repairs/Fuel_Gauge_Repair/Fuel_Gauge_Repair.htm
Logged
Favorite Expression. . . Damned Kids.  Lots of projects.  Donations accepted

Wilfred

  • Newbie
  • *
  • Karma: +0/-0
  • Posts: 32
    • View Profile
fuel gauge
« Reply #2 on: September 03, 2009, 04:45:13 AM »


Hi guys,



I have been wondering why my fuel and temp gauge gave half the reading (a full tank = half reading and temp gauge read beginning of first white line) so I replaced the voltage regulator with a 7805 chip like on Allpar. That chip was a DUD though, so it gave about 10.5 volts cold and probably 14 v @ engine rev. The gauges went full to the right so that was not very handy.



Now I recently made a new chip with a new 7805 and tested it thoroughly on a test bank and this one worked fine.

I let it work a few hours on my table and it worked perfect so I installed it. Now the readings are quarter so the fuel gauge now reads at the first line and the temp gauge between left outmost part and the first line.



I examined the values and the fuel gauge reads about 12 Ohms (full) and the output voltage of the 7805 in car is 5v spot on.



So what can I do best?



Extensive pictures will follow but I'm currently on the iPhone so that will come later.
Wilf2009-09-06 06:41:13
Logged

Wilfred

  • Newbie
  • *
  • Karma: +0/-0
  • Posts: 32
    • View Profile
fuel gauge
« Reply #3 on: September 04, 2009, 02:40:29 AM »


Pictures:











I hope someone can help me with this, I was thinking maybe using a higher voltage chip as both gauges are at approx quarter of normal reading, the only problem is that the chip needs at least 3 volts more than it outputs.
Wilf2009-09-04 07:41:00
Logged

Wilfred

  • Newbie
  • *
  • Karma: +0/-0
  • Posts: 32
    • View Profile
fuel gauge
« Reply #4 on: September 06, 2009, 12:32:34 AM »

and my wiring harness is new and the wiring to the back is checked. It is also very typical that the gauge is not in a normal faulty state (works/doesn't work) but it works good only precisely a quarter of normal.
Logged

Steve

  • Administrator
  • Hero Member
  • *****
  • Karma: +1/-0
  • Posts: 8653
    • View Profile
fuel gauge
« Reply #5 on: September 06, 2009, 05:01:28 AM »

I'm tinkin  I'm tinkin
 
Are you sure you have 12V to the regulator?
Double check the grounds on the dash
Just for the hack of it, change the fuse with a new one
Logged
Favorite Expression. . . Damned Kids.  Lots of projects.  Donations accepted

Wilfred

  • Newbie
  • *
  • Karma: +0/-0
  • Posts: 32
    • View Profile
fuel gauge
« Reply #6 on: September 06, 2009, 12:30:05 PM »




The grounds are good too, this was very important for me because the light switch almost set the car on fire before the wiring harness swap.
Wilf2009-09-06 17:32:36
Logged

Steve

  • Administrator
  • Hero Member
  • *****
  • Karma: +1/-0
  • Posts: 8653
    • View Profile
fuel gauge
« Reply #7 on: September 06, 2009, 03:49:03 PM »

I'm thinking the Circuit board may be building too much resistance then.  Try a balast resistor just for the heck of it.  See what happens.  That's 9 volts
Logged
Favorite Expression. . . Damned Kids.  Lots of projects.  Donations accepted

Wilfred

  • Newbie
  • *
  • Karma: +0/-0
  • Posts: 32
    • View Profile
fuel gauge
« Reply #8 on: September 07, 2009, 07:21:57 AM »

I was thinking the same (resistance), though it is very strange that resistance is so accurate :) I can try to bridge it with direct connections as well. I will try some options this week.
Logged
Pages: [1]   Go Up
 

© 2008-2014 Steve Hobby • © 2015 Allpar, LLC