Author Topic: Fuel Gauge Not Reading Correctly  (Read 3260 times)

0 Members and 1 Guest are viewing this topic.

Offline Hill1430

  • Bone Stock
  • **
  • Posts: 70
  • PSI: 0
  • Boost n00b
    • View Profile
Fuel Gauge Not Reading Correctly
« on: September 29 2023, 12:19:23 AM »
I have installed a Racetronix 255 LPH fuel pump and sending unit. When the tank is full it reads almost 3/4 full. Do I need to drop the tank and play with the float, or am I missing something?
1987 Grand National Work in progress
2019 Shelby GT350

Offline xracerx13

  • NOT
  • Turbo Street Limited
  • ***
  • Posts: 104
  • PSI: 0
  • First Methanol Kits
    • View Profile
    • Joe Tripodi's 1987 Buick Regal Limited T
Re: Fuel Gauge Not Reading Correctly
« Reply #1 on: September 29 2023, 09:40:17 AM »
Did you get the right float. Theres 2 kinds. 1 for digital dash and 1 for analog dash?
Just askin :D
Joe Tripodi 87 Limited T
TA49@25psi, Axis w/chip, LS1 MAF, 60lb Inj, Comp 980s, BGC 23r SLIC, Jay Jackson 62mm TB, RJC PowerPlate, Walbro 307, volt boost 15.8V, Type II ign, Race tranny, 2800 stall, 3" THDP, Pypes 3" SS/Dynomax Ultra-Flos, Meth Inj staged 2 nozzle M5/M10, SS Lift bars, MT ET drags.

Offline Steve Wood

  • Turbo Street Outlaw
  • *******
  • Posts: 9905
  • PSI: 34
    • View Profile
    • http://www.vortexbuicks-etc.com/
Re: Fuel Gauge Not Reading Correctly
« Reply #2 on: September 29 2023, 09:48:00 AM »
I guess I would verify that you had the right fuel sender for your dash first.  If you have a digital dash, it uses a different resistance sender than the standard  sending unit which is 0-90 ohms.    I believe the digital dash was 120 ohms.

At one time racetronix sold a different resistor for the sending unit if you had a digital dash.  You had to remove the 0-90 "rheostat" and install the 0-120 as I recall.

If you have the standard unit and the standard analog dash, the trick was to pull the cluster and clean up the post on the back of the fuel gauge where the connector from the sending unit goes.  That often fixed the problem.

When the tank is full, you can disconnect the connector to the sending unit at the tank and read the resistance to see if it reads the correct resistance at the tank.  Should be either 90 or 120 depending upon the installed sender.  If it reads lower than whichever one is low, you can drop the tank, pull the sender and see what the resistance reads when you hold the float all the way up as in a full tank.

That is all that I can think of at the moment
Steve Wood

http://www.vortexbuicks-etc.com

A lot of broken parts does not make you a racer; it makes you a slow learner.

Offline Hill1430

  • Bone Stock
  • **
  • Posts: 70
  • PSI: 0
  • Boost n00b
    • View Profile
Re: Fuel Gauge Not Reading Correctly
« Reply #3 on: September 29 2023, 01:18:50 PM »
I have double checked and I do have the correct one for an analog dash. I will follow your advice and check the dash and the resistance. Thank you both!
1987 Grand National Work in progress
2019 Shelby GT350

Offline Steve Wood

  • Turbo Street Outlaw
  • *******
  • Posts: 9905
  • PSI: 34
    • View Profile
    • http://www.vortexbuicks-etc.com/
Re: Fuel Gauge Not Reading Correctly
« Reply #4 on: September 29 2023, 06:20:06 PM »
Make sure it reads 90 ohms when the tank is full.
Steve Wood

http://www.vortexbuicks-etc.com

A lot of broken parts does not make you a racer; it makes you a slow learner.

Offline Hill1430

  • Bone Stock
  • **
  • Posts: 70
  • PSI: 0
  • Boost n00b
    • View Profile
Re: Fuel Gauge Not Reading Correctly
« Reply #5 on: September 30 2023, 10:44:34 PM »
I will do that. Thanks
1987 Grand National Work in progress
2019 Shelby GT350

Offline Steve Wood

  • Turbo Street Outlaw
  • *******
  • Posts: 9905
  • PSI: 34
    • View Profile
    • http://www.vortexbuicks-etc.com/
Re: Fuel Gauge Not Reading Correctly
« Reply #6 on: September 30 2023, 11:56:24 PM »
If it does, make sure the tank has a good ground to the body sheet metal also.
Steve Wood

http://www.vortexbuicks-etc.com

A lot of broken parts does not make you a racer; it makes you a slow learner.

Offline Hill1430

  • Bone Stock
  • **
  • Posts: 70
  • PSI: 0
  • Boost n00b
    • View Profile
Re: Fuel Gauge Not Reading Correctly
« Reply #7 on: October 09 2023, 12:12:42 AM »
Shyer filling the tank the sending unit showed 90.7 ohms. I pulled the fuel gauge and cleaned the 3 pins. Now it reads as it should. Thank you for the advice.
1987 Grand National Work in progress
2019 Shelby GT350

Offline Steve Wood

  • Turbo Street Outlaw
  • *******
  • Posts: 9905
  • PSI: 34
    • View Profile
    • http://www.vortexbuicks-etc.com/
Re: Fuel Gauge Not Reading Correctly
« Reply #8 on: October 09 2023, 09:13:08 AM »
Happy to see something worked LOL

On to something else
Steve Wood

http://www.vortexbuicks-etc.com

A lot of broken parts does not make you a racer; it makes you a slow learner.

Offline Hill1430

  • Bone Stock
  • **
  • Posts: 70
  • PSI: 0
  • Boost n00b
    • View Profile
Re: Fuel Gauge Not Reading Correctly
« Reply #9 on: October 09 2023, 09:35:41 PM »
Right
1987 Grand National Work in progress
2019 Shelby GT350

 

SimplePortal 2.3.7 © 2008-2024, SimplePortal