fuel tank sending unit

[esty]

what's the diff in the early and late units...i see them advertised and the ads suggest they aren't interchangeable...i have some early cars i could rob but don't want to bother if they won't work in my 76

mines broken or something's broken a few months ago my fuel gauge started acting screwy...it stayed on full most of the time but occasionally fell to what i assume was the correct reading then minutes later, back to full...

any ideas...is it a bad unit...it's the original 76

[74tiiGolf]

There's a very real chance that your 76 just found the solution to our impending fuel crisis. SWEET!

Matthew

[Mike Self]

accomodate a taller and larger fuel tank on the later cars.

You might try troubleshooting--first make sure the sender's hot lead and grounds are good, then try removing the offending sender and carefully take it apart. Often the problems you describe are caused by a float that's sticking on it's resistance wires, or slack in the wires, or, oddly enough, dirty resistance wires. Also make sure the gauge itself is properly grounded.

I had a unit that was twitching but only when the level was below 3/8 full; above that it was steady as a rock. I took it apart but couldn't find anything obviously wrong. I cleaned the resistance wires and the metal fittings on the float with alcohol, reassembled everything and the gauge is nice and steady now.

cheers

mike

[ariogul]

hi they are sort of interchangable . old ones dont have low fuel level worning light thats why they ahve 2 wires. never sender like above 73 model have low fuel warning light both will fit the same place as long as the lenght matches. bigger fuel tanks have longer sender.

[bluedevils]

hi they are sort of interchangable . old ones dont have low fuel level worning light thats why they ahve 2 wires. never sender like above 73 model have low fuel warning light both will fit the same place as long as the lenght matches. bigger fuel tanks have longer sender.

Euro models are different, I believe US models did not come with the low fuel light switch, early or late.

[emmetHK]

i am having a similar problem and see that there is a lot of information on here about checking grounds etc... However, i am a complete newbie and if there is anyone out there that can help by posting a few pics of what i should be looking for?

 

My fuel gauge has also been reading full.  On occassion it drops which i can only assume is the correct fuel level. 

 

Pics anyone?

 

Thanks,

Emmet

[ray_]

Well you can find any brown wire, trace it to the end and clean the connection

 

Also do the same at the bolt securing the voltage regulator.

 

Search "dash ground pigtail"

 

GL,

 

(edited for silly typos)

Edited February 20, 2014 by ray_koke

[borgpj]

From what I have seen, the gas gauge cylinder up to 1973 was shorter than the later units, like on your car.  I believe the 1974 and later gas tanks were deeper, and thus the gas gauge cylinder is longer.  Using a '73 or earlier sender in a '74 or later tank will result in the fuel pickup being maybe an inch off the bottom of the tank. 

pb

[TobyB]

Also, there may have been a vapor line on one that the other didn't have....  maybe.... he says, thinking back a LONG ways

 

(the tanks vary by era, certainly, both in height and in number of fittings on top)

 

t

 

<edit- oh waffles, those of us who can't read so well are doomed to answer 5- years- dead threads>

Edited February 21, 2014 by TobyB

[jimk]

From what I have seen, the gas gauge cylinder up to 1973 was shorter than the later units, like on your car.  I believe the 1974 and later gas tanks were deeper, and thus the gas gauge cylinder is longer.  Using a '73 or earlier sender in a '74 or later tank will result in the fuel pickup being maybe an inch off the bottom of the tank. 

pb

+1 and to add -  the later tanks had an top half that has a cut out on the fender side to make room for the rear end reinforcement to support the impact bumpers.  And so the filler is not in the same place as the early non-impact bumper cars.  To maintain the same capacity, the tank was made deeper.

[tii74]

What are the actual lengths of the two senders (short and long)?

[borgpj]

The pre-74 units were 7 7/8".  The longer later units were 8 7/8".

[tii74]

I have a 74 tii. So no fuel line connection.

Are there differences for the 74 tii senders too?

[prezucha]

I just removed my gas tank from my '67 1600-2.  Easiest job ever!  I carefully unscrewed the sending unit cap lock and lifted the unit up.  It will not come out of the hole.  The little tabs on the tank opening are preventing it from exiting.  Looks to be a tiny flange (I am probably wrong here) on the bottom of the unit.  I think I could force it but don't want to.  Also the unit body (cylindrical tube) separated from the top locking part.  Looks to be tiny "flaps" that grab a tiny edge.  Is this something that can be repaired?  Seems very delicate.  And what to do about getting the unit out?

Thanks! Paul

[prezucha]

Found another issue that I would like some advice on.  A month ago I noticed some fuel traces on top of the tank.  The sending unit wasn't sealing properly.  I had little gas in the tank so I didn't worry too much about it. Now, trying to lock the sending unit back into the tank, it wouldn't go.  I noticed that the tank has a dent on the bottom and I believe the sending unit is bottoming out a tiny, tiny bit, such that I cannot get the locking tabs to engauge.  My question is, how dangerous is it to try and bang out the dent?  I would use a rubber handled hammer with the handle down in the tank and strike the other end.  I'm a bit worried as I've heard stories of tanks exploding...

 

Thanks! Paul