Fuel Gauge Issue


gtdave16

GT Owner
Mark II Lifetime
Jan 13, 2013
14
Today I turned the key and let the instruments initialize and after initialization was complete the fuel gauge indicated full which is correct. I then started the engine and the fuel gauge immediately indicated empty. I then turned the engine off and went through the procedure again and the fuel gauge indicates full but when started the engine the gauge again indicated empty. I did this several more times and the gauge always indicates full after it is initialized but is sporadic after starting the engine, sometimes showing empty and other time showing full. The battery is maintained on a battery tender. In addition, I replaced the original battery with a Sears Diehard in 2013 and it is properly grounded. I have searched fuel gauge failures but have not come across this particular problem. Any and all help is appreciated.
 

Xcentric

GT Owner
Mark II Lifetime
Jul 9, 2012
5,213
Myakka City, Florida
When my gauges behaved erratically, I loosened and re-tightened my properly grounded ground cable.
 

gtdave16

GT Owner
Mark II Lifetime
Jan 13, 2013
14
I loosened and tightened the ground, initialized the gauges, started engine and the fuel gauge worked. Did it again and the gauge only worked when initialized. I tried a third time and the engine wouldn't turn over, no clicking, nothing. Hooked up the battery tender for 5 minutes, disconnected tender and the engine started but gauge did not work when started but did when initialized. This leads me to believe that it is a battery issue. However, when connected to the Battery Tender Plus (the brand) it shows green, fully charged.
 

Xcentric

GT Owner
Mark II Lifetime
Jul 9, 2012
5,213
Myakka City, Florida
Battery tender is not an indicator of battery condition. It may show green on 12 volts, which is 25% charged. Battery could have a dead cell.
 

AJB

GT
Mark II Lifetime
Le Mans 2010 Supporter
Jun 28, 2006
2,943
Bloomfield Hills, Michigan
need new battery. 5 years is good life on yours.
andy (ajb)
 

twobjshelbys

GT Owner
Jul 26, 2010
6,053
Las Vegas, NV
I agree about first stop being a new battery.
 

maxemus

GT Owner
Mark IV Lifetime
Apr 25, 2007
886
Miami, Florida
Dave
If it turns out that it isn’t the new battery send me a DM and I will fill you in on what it could be.


Sent from my iPhone using Tapatalk
 

nota4re

GT Owner
Mark IV Lifetime
Le Mans 2010 Supporter
Feb 15, 2006
4,176
The battery nor a ground is going to be the cause of an individual gauge exhibiting erratic performance.
 

Xcentric

GT Owner
Mark II Lifetime
Jul 9, 2012
5,213
Myakka City, Florida
How about two gauges? Tach and temp. Bad ground. All other gauges worked.
 

gtdave16

GT Owner
Mark II Lifetime
Jan 13, 2013
14
I had the battery tested at O'Reilly and they said the battery was dead. Their definition of a dead battery is if it measures less that 70% of the CCA rating which is 710 for the DieHard. So tomorrow I will order an Optima battery from the local Ford dealer unless anyone knows of a better battery for a GT. Once the new battery is in I will report back if or not that took are of the gauge malfunction issue.
 

PeteK

GT Owner
Mark II Lifetime
Apr 18, 2014
2,267
Kalama, Free part of WA State
There's a whole discussion on replacement batteries in the Tech Forum.
 

texas mongrel

GT Owner
Mark II Lifetime
May 3, 2009
1,661
Houston Texas
Gauges acting up is my indicator for replacing the battery, fixes things every time. I’m on my third Ford OEM battery, even though they start the car no problem, a new battery cures the gauge issue, I’m guessing it’s an over-sensitivity to voltage drop when initializing the gauges upon turning the key.
 

gtdave16

GT Owner
Mark II Lifetime
Jan 13, 2013
14
Today is my lucky day. I ordered a red top optima battery from O'Reilly at 8:05 a.m. today and it arrived at 1:30 p.m., what service. Installed battery, initialized gauges, started the engine and viola, all the gauges worked. Did it twice more and no issues. Texas Mongrel sure nailed it in determining what was happening. Thank you to everyone for their input.
 

twobjshelbys

GT Owner
Jul 26, 2010
6,053
Las Vegas, NV
Glad to know that everything worked out!
 

Kayvan

GT Owner
Jul 13, 2006
4,782
I had your fuel gauge issue; would swing back and forth.

First it would be at 3/4 then slowly creep down. I even thought I was on slight incline when I started.

Let it go for 2-3 drives; then ALL guages started acting up; would initialize/reset/act up.

Battery was 5.5yrs; replaced with OEM, all good.

Even posted a poll and people swore up and down it’s not related.

http://www.fordgtforum.com/forums/showthread.php/34613-POLL-Battery-Age-(Yrs)-Gauges-malfunction

$209 OEM Battery v . $500-$-1000s in guages, to save pennies getting 6-9yrs from Battery

I just post and don’t even check replies ��