Project 240sx back to life: fuel sending unit assembly

[revenge240]

Hey everyone! Hope all is well.
So finally bringing my 91 240sx with a red top SR20DET back to life after sitting for the past 6 years and need some advice.
I checked the fuel circuit using the FSM and some well documented forum posts and found that on the body/chassis side, everything works (relays, fuses, harness continuity), but the fuel pump is not priming. Thus, I removed it and discovered this:
https://i.ibb.co/xqFw90z/image3.jpg (https://ibb.co/B2nvWxT)
https://i.ibb.co/bHTdCzJ/image4.jpg (https://ibb.co/M8rNtM6)
https://i.ibb.co/Y0wMwkW/image5.jpg (https://ibb.co/jJs2sM5)
The assembly looks bad but I'm wondering if it's salvageable? Can I clean it up, put in new wires and a pump and get it to work, or will I need to find another assembly? Those wires look pretty bad and not sure if I can remove these and put new ones in, anyone ever done that before here?
The fuel level sender actually works and does send the proper level to the gauge so that's okay but the pump just doesn't prime anymore. Of course, I'm going to drop the gas tank and clean it up, but would like to know if this thing is save-able before I drop a couple hundred on a new assembly and pump.
I'll also use this thread to post my build as time goes on so wish me luck! Been a member since I swapped to the redtop back in 2011 so excited to get her running again :squintd:
Thanks in advance!!

[NukeKS14]

Hopefully you can get the tank cleaned out. Was that left half full of e85 for 6 years!? Wow that looks bad. Personally I wouldnt reuse the sending unit. Thats just me.

Ebay or a junk yard is going to be your friend here. Good luck.

[revenge240]

Hopefully you can get the tank cleaned out. Was that left half full of e85 for 6 years!? Wow that looks bad. Personally I wouldnt reuse the sending unit. Thats just me.

Ebay or a junk yard is going to be your friend here. Good luck.

Coincidentally, it was left about half full of 91 or 100 octane gas. I can understand rust if water got into the tank but not sure why the wiring looks like that.
I?ll just have to be patient on finding a used one because $450 for a new sending unit without a pump is a bit pricey.
I might be able to clean most of the rust off this thing but don?t know if I can use regular wiring and solder it up to those connection points.
Thanks!

[NukeKS14]

Yeah always leave the tank full of gas and add Stabil if it's going to sit for any amount of time.

https://www.ebay.com/i/333590605859?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&itemid=333590605859&targetid=883728556789&device=m&mktype=pla&googleloc=9024088&poi=&campaignid=9248481315&mkgroupid=99191196172&rlsatarget=aud-496202329659:pla-883728556789&abcId=1141156&merchantid=6296724&gclid=CjwKCAjw4871BRAjEiwAbxXi2wMjMHnCSqfrxioZfUMM 8ZILGHa9jKlgVwHt-H-UH0DdpHYbLj9dqRoC3HEQAvD_BwE


$200 for a used one...

[revenge240]

Yeah always leave the tank full of gas and add Stabil if it's going to sit for any amount of time.

https://www.ebay.com/i/333590605859?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&itemid=333590605859&targetid=883728556789&device=m&mktype=pla&googleloc=9024088&poi=&campaignid=9248481315&mkgroupid=99191196172&rlsatarget=aud-496202329659:pla-883728556789&abcId=1141156&merchantid=6296724&gclid=CjwKCAjw4871BRAjEiwAbxXi2wMjMHnCSqfrxioZfUMM 8ZILGHa9jKlgVwHt-H-UH0DdpHYbLj9dqRoC3HEQAvD_BwE


$200 for a used one...

Lesson learned for sure. Didn?t know about the tank being completely full before parking it, thanks!
I saw that one on eBay and might have to snag it.

[inky13]

So how's this going for ya? I am in the same exact boat with my 91. I got the sender unit cleaned up pretty well and installed a new pump. But with the tank as rusted as it is, I'm not too keen on running it. I've heard of folks using chemicals (acid or rust cleaners) so now I'm researching what stuff works best. Did you get your tank clean?

[revenge240]

Sorry haven't had a chance to update yet because not a lot of progress just yet but I'll post what I have done:
https://i.ibb.co/FWJh1xP/FCF6-F08-A-A9-E2-423-A-8049-5-B992374-BAA0.jpg (https://ibb.co/g7wr8jn)
Gas tank was very rusted and this was my initial cleaning using a pressure washer and mineral spirits. I ended up purchasing POR-15's fuel tank repair kit that comes with everything needed to clean and seal the tank. Haven't had a chance to do it yet but I will post some pictures when I do!
https://i.ibb.co/Y7KLmC8/73-D75145-102-B-4-DDD-B404-29920-C0-F9-BB3.jpg (https://ibb.co/VWhqR1D)
I ended up finding a used sending unit with a broken float assembly for only $50! Just cleaned my original float and level sensor because it works, and bolted it to this one, as well as a brand new Walbro 255lph fuel pump. Just need to drop it in once the tank is clean.
I also fixed the starting issue that it had (the notorious interlock relay failed) and installed Altima e-fans again since I'm much more knowledgeable on electronics nowadays. Lastly, I accidentally cracked my coolant overflow tank so I installed an aluminum tank since it was a fairly cheap "upgrade"
https://i.ibb.co/gd3sTVC/25-BCDB6-F-844-A-4-F80-90-A9-C232-B7980147.jpg (https://ibb.co/MfsqV6L)
https://i.ibb.co/ch5wqWB/CC259-D87-00-AC-4-C42-9874-17-E4-AAE791-CD.jpg (https://ibb.co/whH7tnk)

She's coming along, but we all know how these things go haha.

[inky13]

Rock on! I hear ya. My excuse was my wife popping out 2 kids... :)

[revenge240]

Rock on! I hear ya. My excuse was my wife popping out 2 kids... :)
Haha that's a pretty good reason to put a pause on a project! Congrats man!
I did so much searching on the right way to clean the tank. Some said muriatic acid, others said acetone, and there were people having luck with even vinegar and water.
I finally came upon the aforementioned POR-15 kit and it includes 2 quarts of cleaner/degreaser, 1 quart of metal prep and 1 quart of tank sealant for around $80, so yeah maybe not the absolute cheapest way but definitely the most convenient since they give you instructions on how to do it all!
Good luck with your project as well and post them pics!

[S14rebuild]

I would never reuse that tank...ull never it get it cleaned enough, even with the sealer, eventually it will flake off and will clog the pickup sock... just a warning

[mechanicalmoron]

If you need a little extra oomph on the tank, a bunch of chain thrown in there can be helpful.

I guess I should go pour a whole bunch of stabilized gas in mine, this is something I've been thinking about more as she sits longer.