[snaped 70 396]

My 70 Chevelle fuel gauge quit working after I took a couple of fast hard turns. Worked fine for 2 years since I bought the car. I pulled the sending unit and it worked fine 0-90 + - a few ohms moving the float by hand. I pulled the dash and found a short in the printed circuit, ammeter was bad so I replaced ammeter and circuit. Didn't help. The fuel gauge did not move when I did the tests I've read on TC, it was pegged past full. I replaced the fuel gauge. Still not working but registered on empty with 8 gallons in tank when sending unit was in the tank. I took sending unit out of tank and tested it in a bucket of water it works the gauge good, E to F. I bought a new sending unit and same deal, works outside tank not inside. The first sending unit has a black foam type float and the new one has a white plastic bulb type. I get a 3-6 ohm reading from the sending unit in the tank with 8 gallons. Sending unit Ground tests good I moved it twice, and power wire from gauge tests good too. Anybody had this problem? We even called "The Tachman", Gary and he is baffled to. HELP!!! Been working on this 3 weeks now

 

[Bryan59EC]

Bad wire between the gage and the sending unit???
Might want to check the rear harness connector under the dash, or possibly where the wire branches off from the harness and goes to the tank

 

[snaped 70 396]

Thanks Bryan, wiring is good, got power to the sending unit. I'm wondering if the sending unit is miss matched with the tank and the float isn't floating high enough. Both tank and sending units are aftermarket first sending unit looks like one from Bobs Chevelles and the new one is a Spectre from Auto Zone the tank is a 34E. I'm going to try attaching the float with a piece of wire in the full position outside the tank then insert it in the tank and see if the gauge keeps reading full to eliminate the wiring ???? and check the float at full in the tank. I may get a 3rd sending unit from NAPA next.

 

[snaped 70 396]

Just looked on Napa.com they sell the same sending unit as Auto Zone Spectre FG91A

 

[DN]

I would make awfully sure the ground wire is good.

 

[snaped 70 396]

thanks Dave, it is

 

[snaped 70 396]

Tested the power wire to sending unit and it has 7+ volts.

 

[john5469]

I'm having same deal. I can take a stiff piece of dowel and go in the filler neck with a flashlight and lift the float up manually and the gauge goes up.

 

[Bryan59EC]

I think some on this board have removed the float from the sender and replaced it with a
brass Ford float-----hmmm. maybe not brass, but something much better than aftermarket.

I just replaced a sender on the 65 Ranchero----it has a plastic float.
Gage will not go to full but show 1/8 with 3 gallons (close enough)
Will probably get a brass float for it later---when I get the rest of the bugs worked
out of this car that had been sitting for about 5 years.

 

[snaped 70 396]

I'm going to check it tonight with a flashlight / mirror to see what will happen. I'll keep the brass float in mind. I had a 66 Mustang with a brass float that leaked once upon a time. Thanks guys for your input, I'll keep workin and @!%?*#@.

 

[Tom Mobley]

somebody here had a re-pop sender that had a plastic float. the float was made of a plastic that was heavier than gasoline so it sank to the bottom. floated fine in water, water is heavier than gas. try the float in a bucket of gas.

cheap china junk......

 

[Coppertop]

Hey! I was the poor SOB that had the float that did not float!

Read all about my "wonderful" story and what it took just to get a worthless sender to work...

http://www.chevelles.com/forums/showthread.php?t=333596



Also, I would strongly suggest you guys do not use a dowel or broomstick or anything to shove down the filler neck to "work" the float. I seem to recall there was even Chevy TSB (technical service bulletin) for dealerships back in the early Corvette days. The risk of introducing a static discharge is there and you could cause an explosion.

Some food for thought.

Joe

 

[Dave69Z]

I had a problem in my 69z28 that was quite similat. The float seemed to stick to the bottom of the tank and worked fine out of the tank. after some research i found two problems. 1. the float is rather stiff on the rheostat when new. 2. the ribbon cable is rotated away from the middle of the sending unit and shorts to the tank. My ribbon cable insulation was frayed towards the top of the cable so i rotated it towards the middle of the sending unit. I also made sure the sending unit was not skewed to that side when i installed it. I worked the float a little before i put it back together and its been working fine for a year now.