TR6 TR6 Fuel gauge help

[ichthos]

Hello,

My car has been sitting since mid October and I finally had some nice weather to pull it out of the garage, put the dash back together, and start it up. I have not hooked up the tachometer or installed the glove box yet because I need access to the windsheild wiper areas under the dash. All the gauges seem to work except for the fuel gauge. I cleaned the connections at the tank and gauge. Just to be sure it was not the gauge, I hooked up a spare fuel gauge, and it did not work either. Both gauges showed my tank a little less than 3/4 full even when the tank was topped off in October. Could it just be a matter of the sending unit having a leak in the float? I had planned on pulling the tank and taking a look at the sending unit this summer, but I just want to have a little fun for now. Is there a way to check the sending unit without pulling the tank? Do you have any other ideas on what I should check? If it a matter of grounding still, where else should I check? Other ideas? Any suggestions would greatly be appreciated.

Kevin

 

[TRopic6]

Kevin,

The sending unit's resisance varies as the float arm moves from full to empty. You can hook an ohmmeter across the two sender terminals and pull the float arm up (and push down, although that's much trickier!) I used a coathanger wire and a flashlight. Hint - it's easier at night. I think it should vary from about 25 ohms (for full...I think) to 280 ohms.

My car sat for 10 years and I had to dismantle the sender and clean the inner connections. It's pretty straightforward.

Jeff
CF13816U

 

[2wrench]

Read a thread on the forum about two gauges acting up
at the same time: Both Gas and temperature. Guys had some
success in correcting their problems by replacing
the voltage stabilizer. (Messes up the gauges if bad).

I am just quoting to you what I made note of. I have
not personally done this repair. Found and reviewed the
thread to assure my info per their post is accurate.
Something to consider.

 

[TexasKnucklehead]

My 74 TR6 sending unit reads as follows (with an ohm meter):
0 ohms = full
52 ohms = half
128 ohms = 1/4
I didn't run it out of gas to get another reading, but the gauge functions fine. I only measured it because I'm trying to figure out why my TR3 sending unit does not work with a TR4 fuel gauge. The TR3 sending unit seems to be wired on the opposite end of the wiper, with a different resistance. I'm still trying to figure it out...

You can short the wire at the sender to ground, and the meter should show full. The tank and meter should both have good grounds.

 

[TR674]

Kevin
thought I would throw my 2 cents worth in.
I recently took my speedo out to get it serviced. I drove the car a few times with the speedo out, and neither the fuel or temp gauge worked. Once I re-installed the speedo all was working well. I'm not sure if the taco has the same effect, but try reinstalling it and start the car to see if this fixes the problem. Just a suggestion, as I'm pretty much electrically illiterate.
Regards
Craig

 

[dklawson]

If it's just the fuel gauge and the temperature gauge (presuming it's electric) is acting normally, focus on the fuel gauge, its wiring, and the sender. Normal temperature gauge operation implies that the voltage stabilizer is OK.

Since the gauge is reading something you know that there is power. Use the coat hanger test mentioned above. Try both lifting the float up and pushing it to the bottom while you observe the gauge. If lifting brings the reading to "full", take a close look at the float as you suggest. Remember when using the coat hanger that the gauge responds slowly and give it time to react.

 

[roofman]

TR674 when you removed the speedo, the voltage stabilizer is attached. If you disconnected the stabilizer wires you will get no fuel or temp guages ( at least).

 

[Tinster]

Both gauges on the Crypt Car were wacky
until a new voltage regulator was installed. Then
the entire car rewire did away with the need of the
VR completely.

With the tach out, and original wiring-neither gauge
will function.

d