Fuel gauge no-op


t32b

Verde
Mark II Lifetime
Jul 21, 2007
432
Bay Area, CA
Folks, I'm sure this is a repeat but 'search' was not my friend. Feel free to send me to some old threads if it's been played out before...
Like many others, I have had gauge problems with my FGT. Most were fixed quite simply via a combination of a fresh battery and a touch-up to the ground wire in the battery compartment. But my fuel gauge remains dead. It's stuck on 'full' and won't move. I've been using the trip odo to keep me from breaking down on the side of the road but my type-A personality requires me to take some action and get it fixed. The problem is, how can I be sure it's the gauge and not something else? I am concerned that in being stuck on full, it might be a stuck float (once, quite some time ago, after refilling the car from a near-empty tank, it took the gauge at least five minutes before it moved from empty back to full - it felt like the float might be stuck).
So, I am looking for some advice on debugging the issue. Specifically, is there anyway that I can determine in a straightforward manner whether or not it's the gauge? I could order one from Torrie but I doubt I could return an electrical part if it exhibited the same behavior. If I pull the dash and the gauge, can I put a meter on the wires and determine if the electricals are properly working? I don't trust the dealer, and Shadowman is a bit far away for a problem as small as this. Too bad hand models don't do house calls :)
Rich
 
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BlackICE

GT Owner
Nov 2, 2005
1,416
SF Bay Area in California
99% chance that it is the gauge. The easiest way to test it is to have use a Ford diagnostic tool to move the gauge needle, it if doesn't responded to the commands it is not the fuel level sender (which I believe is ultrasonic), it is the gauge or gauge control module. Again 99% chance it is the gauge. Any Ford dealer should be able to do this be just plugging the tool into the OBDII port.

IMO I would go with a complete new Speedhut setup and save the OEM gauges to go with the car for the sake of originality.
 

ViperJoe

GT Owner
Mark II Lifetime
Aug 17, 2006
1,305
Washington Crossing, PA
It's a faulty gauge. Welcome to The club. Replace all the gauges usingg the speedhut set
The oem gauges are trash.
 

t32b

Verde
Mark II Lifetime
Jul 21, 2007
432
Bay Area, CA
Thanks. Yes, I'd like to pack away the oem gauges and install the Speedhut gauges, but want to make sure that: 1) I pack away a working set of gauges and 2) that when I replace my gauges with the Speedhut set, that I'll have a working fuel gauge. Sounds like the best thing to do is to drop by Ford and have them test the gauge via their tool (does anyone have one I can borrow? I have had a bad experience with my local Ford dealer) and, assuming it's the gauge, I'll purchase a replacement and the Speedhut set.
Is there any forum or group discount for the Speedhut stuff? It's actually a good deal regardless but thought I would check.
B
Edit: BTW what are people choosing as the gauge design (lettering font and color, background color, shift light or not)?
 
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ViperJoe

GT Owner
Mark II Lifetime
Aug 17, 2006
1,305
Washington Crossing, PA
White Euro font, black faces, white pointers, no shift light, silver bezels
 
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twobjshelbys

GT Owner
Jul 26, 2010
5,633
Las Vegas, NV
My gauge told me I was about 1/4 full so I filled up this morning on the way to the Horsefeathers show.

It took the right amount (don't remembver exactly) but my calculator told me I got about 16.5 MPG on the last tank.

The gauge took forever to get to "full". It just crept along. I thought it should have just snapped to full but it just crept up. Almost spooky but I got through Boulder without a stop so didn't get a chance to stop the engine and see if it came back after a power down. After the next start after the show is done all is well and the fuel gauge shows the correct amount and just snaps back to the right place after turning the key off and on.

Anyway, I thought I was about to order the new gauge kit but got a pass for a while.
 

33Bravo

GT Owner
Mark II Lifetime
Nov 3, 2006
686
Minneapolis, MN
I let my fuel tank get very low on our Dyno day in Minneapolis w/Torrie (had racing gas - wanted a second tune with pump gas). Filled up with about 15.5 gallons (1 remaining). The fuel gauge remained at empty (as well as the check gauge light). As I was pulling back into the dyno shop - the gauge popped back to "full" - been working fine ever since. Phew.

I'll be getting the Speedhut set...
 

BlackICE

GT Owner
Nov 2, 2005
1,416
SF Bay Area in California
White Euro font, black faces, white pointers, no shift light, silver bezels

Euro font, red pointers, with blue backlighting silver bezels, no shift lights.
 

RALPHIE

GT Owner
Mar 1, 2007
7,279
My gauge told me I was about 1/4 full so I filled up this morning on the way to the Horsefeathers show.

It took the right amount (don't remembver exactly) but my calculator told me I got about 16.5 MPG on the last tank.

The gauge took forever to get to "full". It just crept along. I thought it should have just snapped to full but it just crept up. Almost spooky but I got through Boulder without a stop so didn't get a chance to stop the engine and see if it came back after a power down. After the next start after the show is done all is well and the fuel gauge shows the correct amount and just snaps back to the right place after turning the key off and on.

Anyway, I thought I was about to order the new gauge kit but got a pass for a while.

I let my fuel tank get very low on our Dyno day in Minneapolis w/Torrie (had racing gas - wanted a second tune with pump gas). Filled up with about 15.5 gallons (1 remaining). The fuel gauge remained at empty (as well as the check gauge light). As I was pulling back into the dyno shop - the gauge popped back to "full" - been working fine ever since. Phew.

I'll be getting the Speedhut set...

Check my post -

http://www.fordgtforum.com/forums/s...peedhut-Gauges&p=311879&highlight=#post311879

I would start looking for a replacement battery for each of these instances. As I noted in the referenced post, I never let the condition of the gauge remain in the aberrant condition, but would restart the car until a normal condition was achieved. The starter motor is dropping the battery voltage (due to its hi amperage load) to the point where the gauge control unit does not start up properly. I'm pretty sure that these problems will go away if you replace your batteries.
 

twobjshelbys

GT Owner
Jul 26, 2010
5,633
Las Vegas, NV
My battery is brand spankin new - installed by Rich when he dd the mods in October, and it's on the battery tender if it is going to sit for more than a few days (that means, generally Sunday PM through Sat AM).

The gauge was fine when I started the car up in the morning. Since the gauges are a paranoia point I always check them whenever I start it up to see if they work. It was when I filled it up with about 1/4 tank, and just took forever to move to Full. I didn't hit any red lights before it had corrected to turn off the engine and on to see if it would spring back to normal, but when I did (and it had crept back to Full) it behaved normally.