1978 280z gas tank sending unit

[Dads280Z]

Hi read some old posts but could not find where to buy a new sending unit can any one give me a web site thanks

[biddljj]

http://www.thezstore.com/page/TZS/CTGY/SFC04D

Not just a Z - zdisease

[biddljj]

Does anybody have advice on how to test a sending unit ?

Context: I think my 72 240Z is not sending true status of gas tank level.

Thanks, Jay

Not just a Z - zdisease

[Jeff G 78]

http://www.thezstore.com/page/TZS/CTGY/SFC04D

Not just a Z - zdisease

There are no new '78 sending units. I had trouble finding a new one a few years ago. I contacted Danny's Datsuns in Oregon and got a used one for about $30. It turned out to be my dash gauge, but my old sending unit was in bad shape anyways. All works perfectly now.

[TomoHawk]

Good point Jeff,

I had a little trouble with mine in the 78 because it was reading about 1/4 tank when I was really empty. After cleaning the connections (the gauge connection apins and the sender plug pins) It was corrected. I used Deoxit on the pins to clean them.

The local place that reseals the gas tank (gastankrenu.com) will also do the sender unit, so you might consider that instead of getting a new one.

thxZ

[sblake01]

Does anybody have advice on how to test a sending unit ?

The test is pretty simple. This is for a 280Z and might differ from the 240Z. There are three terminals that correspond with the black wire, the yellow wire and the yellow/blue tracer wire. The static resistance between the black and the yellow wire is 10 to 80 ohms. When submerged in fuel (or just carefully move the float to that position), check the resistance between the black and the yellow/blue. Remove it from the fuel and check that same resistance and it should differ from the previous step. If it stays the same, the sender is either defective or the resistance wire coil and needle aren't making good contact and need cleaning. Edited July 22, 2009 by sblake01

[TomoHawk]

There are other topics here regarding the resistance values of the sending unit.

[sblake01]

There are other topics here regarding the resistance values of the sending unit.

True but this was originally started by someone with a 78 and I answered accordingly even though the question I answered was posed by someone with a 72. I was just attempting to more or less stay on topic.

[sekjr]

There is a sending unit for sale right now on eBay - and the guy wants a fortune. Anything being sold by 'reddat' is expensive. I won't deal with him. BUT

BUT

BUT

you can fix it yourself. What I found to be the problem is that the wipers are NOT grounding properly.

ALSO:

The wire terminals are riveted to the top plate -- and rotate -- meaning they are NOT making good contact.

FIX?

Soder jumpers from the indivdual rivets on the underside of the plate to the individual wires with a pencil sodering iron.

Soder small jumper wires from the wipers to ground. A convenient ground is one of the screws holding the framing together....

If you have any questions on procedure, contact me...

[cygnusx1]

In the sender I had, the windings had gotten loose and the wiper was catching on the windings.

I used cyano-acrylate CA glue, like crazy glue, to put a layer down over the windings. This bonded the windings to the board and fixed them in place. Then I sanded the top of the windings lightly to re-expose the metal. I tested it afterwards and it worked smoothly and accurately. The CA "should" hold up in fuel. We will see, as I get the car on the road this Spring.

[Mikes Z car]

This is an old thread but an idea to lenghten the life is to slightly shorten the copper swing arm so that it slides across a different arc of resistance wire in the case where there is a lot of wear on the wire from the copper contact arm. This can be done by removing the cover over the copper arm and bending it to look like (side view):

Original from factory ____________

New look _____/\_____

I am putting details and pictures of this on my blog in case anyone else wants to see it.

[cygnusx1]

Thanks for reviving this. I forgot about it. As a follow up, I have had zero issues with the fuel sender since gluing the windings into place with CA. It has been perfect.