I replaced my 1985 Analog 300zx fuel sending unit with the updated new design (see attached pictures).
All working fine.
The question I have is for another 300zx owner who approached me about his fuel sending unit.
So we need help to figure out how to differentiate between a Digital FSU and a Analog FSU without the donor car present.
Any one has experience how to differentiate between Original Digital FSU or Original Analog FSU ?
Is there an actual visible difference between an original Digital and Analog FSU?

We were going to purchase an used original one, the seller had 2 of them, he told us one is from a 300zx with Digital Dash but does not know which one is which.
We compared both of them to my old original FSU and could not see any difference at all between any of them.
The only difference we could see is one had a black harness, the other has a white harness, my original one has a black harness.

The seller could not tell us but supposedly the digital unit has a silver box next to the connector of the fuel sending unit.
It is Digital If there is a silver box 2506517p15 when the rear carpet/mat is removed on the right side (passenger side) approximately 8 inches from the FSU. Supposedly if there is a silver box with the number 2506517p15 it is a digital fuel gauge.
Analog dash cars don't have the silver box.
This silver box is an FSU Adapter for Digital Dash.

I have read that some have used the same sending unit on both Digital and Analog and it worked fine because the silver box with the number 2506517p15 is the one doing the digital conversion. Is this actually true?

I read "This box is what converts the analog signal from the sender to digital for the GLL dash, though strangely not all digital Z's seemed to have it."

New sending unit

My Original Analog Sending Unit.


My New Fuel Sender Unit Installed

Any one has experience how to differentiate between Original Digital or Analog FSU ?
Thank you

 

The digital unit has a white sheath covering the wires, Analog is black as in the picture.

There is a 2 float unit to replace the foam floater if you can find it, it too has white sheathing covering the wire. I accidently ran up on one on Ebay, immediately grabbed it and ended my fuel level problems. Very hard to find a working OEM unit. Got several.

I am using the same converter box with the 2 float unit that was connected to the original float unit. Works perfect.

 

Hi Guys, just joined the Forum from Oz. I have fully restored my Z31 over the past 7 years from a " Barn find" shocker! . Am interested in where to buy the after market fuel sender unit pictured above. I am going crazy trying to find a working replacement for my '85 non-turbo analogue dash Z31. Have had at least 4 from OZ Wrecking Yards all of which were dead. I will really appreciate your help. Thanks and best regards Corkboyo

 

Are you trying to replace with OEM can units? If you are, save your money, got several that "worked" according to seller, junk for the most part. If you are analog the sheath covering your wires should be black. If so there is a 2 float unit that will work on your car. If you swap it and it still doesn't work, it could be the little silver signal converter box right by the cover next to the sending unit. Mine was digital and just happen to run up on a 2 float replacement with white sheath covering on Ebay and grabbed it., the color of the covering is the difference in the 2 units. Got rid of the can and so far no problems, right on the money. I think I have a signal box if you need one, let me know.

 

Hi, hanks for your msg. NO, I have had it with those units- so difficult to find either a working one or an honest Wrecking Yard!!.. I actually found a reference to the 2 float model at Courtesy Nissan in TX, but they replied overnight that they are discontinued and nil stock, ( even tho' their website say they have "at least 1 in stock" ??? ) Any leads to find one in the US will be greatly appreciated. I have trolled eBay with out success - I had found one some time back but the guywould not ship to Oz.
Cheers

 

The one from Nissan won't work, it has black sheath on wires. Is that one still on Ebay, I will check it out for you. Yes they had a recall finally i think in 84 and the replacement had both the 2 float and converter. I have been as far away as Russia and Saudia Arabia. No luck. There are 2 places in Japan you can buy brand new parts if they have them and they have had most of mine. Amayama.com and Japanese Genuine OEM Parts. Fast shippers too. Good look. When you got to Ebay, put in 1984 300ZX parts, lot of junk will pop up, scroll down left side until you see "Used" check it and then go up and check new listing. How I found mine.

 

Hi again, thank you so much for your offer and your tips. I have located one at AMAYAMA and have sent an enquiry. They have a branch in Sydney Aus and web says they have it in stock. Have asked if it is upgraded 2 float unit, so fingers crossed. Will let you know what happens... Thank again for your help. Cheers

 

Hi again guys,

Hey macanic, I located units on AMYAMA and JP carparts.com websites showing units available, only to eventually get reply "unit discontinued" Why do they do that, get your hopes up them pull the trapdoor lever????.

You mentioned that the black sheath cable OEM replacement unit that DGS showed in his post doesn't work, yet he says working fine. I have located one of those units at the ZStore in CA. see link below. Would you be kind enough to check it out and let me know if it is OK. I note that it has 4 wires whereas mine has only 3 - red black & yellow.

DGS, where did you source your sender unit from? Is this the same supplier.

I have tracked another used can unit in WA ( oh that's Western Aus - not Washington State) but guy not in a hurry to respond.

Incidentally, I have a son in Seattle WA so could have the unit sent to him. He travels to OZ quite a bit, but not this year due to the 'Toyota 'Virus so probably best to have it shipped here direct even though I would have to hand over a couple of grandchildren to cover the freight!!!!!
Will appreciate any advice you can give. Meanwhile you and yours stay well. Regards, Bill https://www.thezstore.com/page/TZS/P...c17d03/11-3331

 

Oh, I forgot to mention that my original unit has blue sheath on cable, like all the others I have seen in OZ analogue dash vehicles. Cheers, Bill

 

Do you have one for sale? If so, how much. Thanks!

 

Try here
300zx Parts For You webpage