55 T-Bird gas guage

G

Grumpy Rick

Senior Member
On to the next problem in getting this bird sorted out.

My '55 Bird is basically stock, and has been converted to 12 volt before I bought it.. I just ran out of gas in it, and the gage was reading between 1/4 and 1/2 full. Using a flashlight, I could see no gas in the tank.

Is there maybe something that needed to be changed (like maybe a resistor) during the conversion? I have heard it both ways.

Could it be a problem with the sending unit?

Any advice on what to check first would be appreciated.

Rick
 
If the car still has a good oem gauge & sender they should not need any extra parts.
"The ('55) fuel and temp gauges will work on 6 or 12 V and are not polarity sensitive."

 That said, there is a just-in-case note about a wire-wound resistor at the bottom of this page / link. (not an electronic voltage regulator, they don't work the same)
https://www.ctci.org/gilsgarage/6to12.php

You could also bend the float rod slightly upwards and give that a try.

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make sure you have a good ground.
you can pull the sender and do a ohm test to see if it is working
Does the rest of your instrument lights and gauges work?
Those old voltage regulator for the instrument group can go bad
In my 74 Dart I built and installed a electronic unit... will not go bad.
BTW the instrument group is usually 5v + -
If interested the info can be found using a google search
Another interest might be using solenoids for the head lights. this takes the current
out of the light switch, and puts it on the solenoid. making the lights brighter and
letting the headlight switch last longer...
Best
 
Sanddoc said:
make sure you have a good ground. ....
Those old voltage regulator for the instrument group can go bad ....
Click to expand...
Yes, double check that there's a good ground connection from the sender to the car body.
Ford didn't use a dash gauge voltage regulator until '57.

Here's a diagram of what I believe is the oem '55 fuel gauge & sender setup.
The bi-metal activated contacts in the Sender control the amount of current thru the circuit, and the heat generated inside the gauge that moves the indicator needle.
Because movement of the gauge needle is controlled by heat and not directly by voltage or polarity, it doesn't always respond to electrical alterations as expected.

The internal electrical specs of the '55, '56 & '57 gauges and senders are each-year-only specific.
Individual oem style replacements are available from the usual T-Bird resto shops, as are 6v to 12v conversion 'replacement style' gauge / sender pairs for the 55's.
The resistance between the contacts of a '55 fuel gauge should be 11-12 ohms.
('56 = 38 to 40 ohms, '57 = 13 to 14 ohms)
These spec's for the fuel gauges are shown in the Hill's Tbird parts catalog, pg 66.

If you have the sender out of the tank you should be able to leave the wire from the gauge connected and carefully (no sparks please) ground it to the car with a jumper wire and test how float arm movement affects the gauge readings. Comparing float arm movement to the depth of the tank.

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dmsfrr

Sorry did not think,
Talk about not thinking.. the cars back then were 6v It's after the conversion to
12v that they used VR in Dash...
Which is always been an interesting question why have a step-down VR?
 
Thanks guys,

In any case it sounds like my first step is to check the ground. Then pull out the sending unit and see if it needs adjusting.

It seems to work ok. When we ran out, my son brought us 5 gal of gas, and the guage went to full. Hopefully it will be a straight forward fix, and not my usual round robin.

By the way. I never could spell it.......is it gage, guage, or gauge? I feel like an idiot every time I type it, and my spell check is no help.

By the way, I now know why the car shifts immediately into high gear. I looked up how to adjust the kickdown, then found it is missing on the car. I suspect the previous owner had lots of parts left over. This will be a near future posting, as soon as I get to it. For some reason, the wife wants me to finish her kitchen.
 
Yes check that the sender is grounded. Several months back when someone else went thru this we never did figure out how Ford expected the sending unit to ground itself. The tank has cushioning pads top & bottom between it and the body. Adding a 'sender to body' ground wire won't hurt.

If adding a 10 ohm 10 watt wire wound resistor into the gauge power wire is easier than replacing the old sender gasket you could try that first. Removing the sender does give you the opportunity of checking the debris content of the tank. (how fun?)
The tank in my '55 was rusted thru, leaking in two places and the sender was worse. I put in a new tank and also got a new 6/12v conversion gauge-sender pair to improve the odds of it working better.

'gage, guage, or gauge?' I can't spell it right the first time either. The spellchecker always catches me and it prefers 'gauge'.

Missing parts? Four plus years into this one and I'm still discovering things I didn't know were missing.
A couple big Honey-do's and some family medical problems have been stalling work on the car. If there were a resto shop near me I was more comfortable with, I'd consider sending the car there.
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Thanks for the help guys.

It will probably be a couple weeks before I get to it, but I will let you know what happens.

I took it out for a ride, filled up the tank and drove about 15 miles, then the car started acting like vapor lock, and I turned around and limped it home. I wonder if the points are burned again. It had a full, clean, fuel filter at the carb, but I suppose it could be something wrong in the fuel system again. I haven't put the pertronix on it yet, I want to get everything else straightened out first.

BTW DM, I looked in my huge dictionary, and it is spelled gauge, with gage being commonly accepted in the US. Gotta order transmission linkage....10% off at Larry's this week.
 
Sounds like you have a coil that is bad. Mine would run fine until things got warm and then the coil would break down inside. New coil and Pertronix fixed it. Good luck!!
 
On the vapor lock thing, make sure the vent tube is not blocked. Dirt daubers like to get into things like that and mess with your mind. I've had more than one experience with blocked vent tubes. Good luck.
 
Grumpy Rick said:
What vent tube would that be? ...
Click to expand...
He may(?) be thinking of the vent tube on the fuel tank filler neck of a '57 Bird.
The '55 & '56 don't have one.
Bowl vent tubes on the carburetor? They're inside the air cleaner. I'm confused too.

Grumpy Rick said:
I took it out for a ride, filled up the tank and drove about 15 miles, then the car started acting like vapor lock, and I turned around and limped it home. I wonder if the points are burned again. It had a full, clean, fuel filter at the carb, but I suppose it could be something wrong in the fuel system again...
Click to expand...
IIRC, you replaced the teapot with an Edelbrock. Is there any chance some dirty fuel that went thru a bad filter got into the new carb?
Some Holley carbs have an internal filter screen between the inlet line and the float valve, just inside where the fuel line attaches... maybe the Edelbrock does too? If it's a bit clogged it will act up.

If it's burning the points it won't hurt to replace them and the condenser, they could be a cheap/off-shore made set.
Since it's a '55 converted to 12v you could also double check the ignition & ballast resistor wiring.
The red/green wire from the "C" (coil/run) terminal of the Ign key switch connects to the (new) ballast resistor, then to the "+" terminal of the coil.
A new wire from the "I" terminal of the (new 12v) starter solenoid connects directly to the "+" terminal of the coil.
The car will start & run if these two ignition power wires are reversed at the resistor & coil but the 'running' voltage will be too high and eventually burn the points.

If you want to see the wiring diagram larger it's at this link.... and you can zoom in on it.
http://www.oldcarmanualproject.com/tOCMP/wiring/5765wiring%20diagrams/Ford/MWire5765-195.jpg

Lots more of them, '57 to '65....
http://www.oldcarmanualproject.com/tOCMP/wiring/5765wiring diagrams/fordindex.htm


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Getting back to the faulty reading on the gas guage, you said originally that the guage reads 1/4-1/2 full when the tank was actually empty.....then later said you son put in 5 gallons and the guage reads full. At least that makes sense. It sounds like the factory settings of guage itself have been tampered with by the previous owner OR, someone has bent the sending unit float arm downward quite a bit. I second the motion to add a ground wire attached to one of the sending unit hold down screws. Needs to be a good clean connection attached at other end that is known to have good conductivity. (I used the grounding terminal where the wire harness goes thru the firewall).
Anyway, maybe nothing wrong with the guage. Try bending float arm upward until the guage reads empty when the gas tank actually is empty.
I don't know if I spelled it right either. My hands just instinctively type it that ways always????
 
Like I said, I have not gotten to it. Pretty busy with the house, and it's too darn hot in the garage.

DM..you are correct, I have no vent tube on the tank. BUT the gas cap is not vented either. When I took it off to check it sucked air, so I left it loose on that trip home. Didn't seem to make any difference.

A month or two ago, I replaced the dist with a rebuilt '60s 292 dist off ebay. New points condenser, cap and replaced the coil. The resister looks new, and the dist is hooked to the lug opposite where the full 12V comes in.

I also bought a Pertronix setup, complete with coil, and I will put that on next, eliminating the resistor altogether. I suppose the new points might be burnt already with only about 30 miles on them. At this point I would not be surprised.

I replaced the fuel filter with a clear plastic one, as the old one had a bit of visible junk in it, not much though. The new one shows nothing. I suppose I should pull off the top of the Edelbrock just to make sure there is nothing in there.

Still got the regular fuel pump on it, and when you crank the motor it flows pretty good. I also have that new electric pump I plan to put on as a backup, but not installed yet.

I would think about vapor lock, but the temp gage says 160-70. I have never seen the motor get hot, and it was over 90 when we were driving it.

I found out why the trans doesn't shift right. The entire kickdown linkage simply isn't there. I will start another thread on that one, when I get to it.

If I ever get this thing done, I think I will write a book. You guys are probably thinking I already have.

Rick

PS: So...is the gas cap supposed to be vented? If so, what size hole should I use?
 
Ok so we're way off your original gas gauge topic, what the heck, it's your thread and I'm successfully avoiding pulling a gas tank.
Grumpy Rick said:
....
A month or two ago, I replaced the dist with a rebuilt '60s 292 dist off ebay. New points condenser, cap and replaced the coil. The resister looks new, and the dist is hooked to the lug opposite where the full 12V comes in.

I also bought a Pertronix setup, complete with coil, and I will put that on next, eliminating the resistor altogether.

If I ever get this thing done, I think I will write a book.

the gas cap is not vented either. When I took it off to check it sucked air,
So...is the gas cap supposed to be vented? If so, what size hole should I use?
Click to expand...
The coil is polarity sensitive. It can act up if connected backwards, not sure why.
I figure the terminals wouldn't be labeled + and - if it didn't matter, might have something to do with the direction of the spark across the sparkplug electrodes...???

When 55's were new and 6v positive ground the '+' terminal was connected to the distributor wire for the points. When converted to 12v neg ground the wiring on the coil terminals needs to be reversed.
The '+' terminal should have the ignition power wiring connected to it and the '-' / 'dist' terminal connects to the points in the distributor.
The possible reversed wiring I previously suggested checking was the two different wires coming from the ign key switch & starter solenoid, that separately go to the ballast resistor and ign coil.

Yes the gas cap should be vented. Since yours isn't you could replace it with a repop '55 correct one, or make a hole as you mentioned. I'm thinking it should be really really small and somewhere(?) in the cap that doesn't allow gas to dribble out when the tank is full and sloshing around. https://www.youtube.com/watch?v=y6ZAKtrCrfI
FYI, the vented reproduction '55 caps are recessed in the center, apparently to clear the emblem mounting hardware on the underside of the fuel filler door. (if that's a problem)

A book? We already have, it's in all these FordBarn pages. We just need someone to compile it. :rolleyes:


I took the liberty of copying a previous post of yours that should help others reading this determine when a ballast resistor is or isn't needed with a pertronix ignition unit. The answer is...
'It depends on which coil you're using.'

Grumpy Rick said:
......
I just got off the phone with Pertronix tech support, which answered my questions about resistors.
The instructions for the Ignitor state that if the car has a resistor, to use it with the Ignitor. The instructions for the coil state that if the car has a resistor, to remove it.

Per tech support, some cars come with external resistors, some have internal resistor coils. On old cars they sometimes get mixed and cause ignition problems. The Pertronix coil has an internal resistor, and therefore I should remove the original external resistor. If I had used a stock original coil with no internal resistor, I would use the external resistor.
Click to expand...

How to check if an unlabeled coil needs/doesn't need a resistor for a pertronix module installation...
http://www.pertronix.com/support/tips/#a2

"What will happen if I leave the ignition switch on when the engine is not running?" (Poof!)
http://www.pertronix.com/support/tips/#a3

.
 
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Leaving the key on with the Pertronix I is an issue. Not so with the III. Just installed one and you have to leave the key on to set the rev limiter and it takes more than 30 seconds. Not sure about the II.
 
It has been hot and unusually humid here lately, and it gets to me. My garage is tight, and has a lift, and I cannot open the hood inside to work on the car. I finally got a nice evening yesterday and checked the coil, points, wiring, and fuel filter. All are ok.

While idling the car started stumbling again, and I could see the fuel filter was full, so I guess it is now time to open the carb and see if there is any junk in there from before I put the new filter on.

It was acting like there was water in the gas, but it seems like I should see some evidence of that in the clear fuel filter.

I will try working on it next week, when my wife will be home from a trip, to help push it back into the garage.
 
Well, a mechanic buddy and I pulled the top of the carb off yesterday to check for junk or water in there, as well as the float bowls. Everything in there was fine.

So we still haven't found the problem, but we have eliminated one more possibility. Next time we will remove the fuel gage sender, and check the sock in the tank, as well as pressurizing the tank a bit and seeing if any junk is in the fuel lines up to the pump.

No gas in the oil, fuel pump keeps the filter full, no new crud in the filter, I drilled a 3/32 hole in the gas cap, and the tank has no visible junk sloshing around in there that I can see by sticking a flashlight in the filler. Vacuum gage shows a nice steady 19 inches.

The car still just idles great until warmed up fully, then occasionally stumbles and wants to die. Haven't actually driven it any more yet.

To be continued....
 
I just wrote a new post about the gas gage, since this thread is getting old, and going in several directions.

Follow up report:

I took the car to a mechanic who specializes in hot rods. He worked on the gas gage, and says I need a new one....See latest thread.

I had done everything I could think of on the fuel system and ignition, except install the new Carter electric fuel pump, and install the Pertronix. He did both those for me and same results........start and die after a short time.

He then wired the ignition to another hot source, and boom..problem solved. The car has been driven about 70 miles since then with no problems. Apparently there was a bad connection or wire in the ignition source.

Thanks very much for all the answers and suggestions.
 
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