I believe that the foam floats dont have the problem of taking on liquid like the brass ones do but could be wrong.
You could have shook the float and if it had fluid in it you would know even without removing it from the sender arm.

Have you shorted the sender wire to ground to see if the gauge moves for that tank? if it does not you will need to check only that side of the gauge for a problem.

As for the color it looks pretty close to the offroad fuel and I bet if you were pulled over and they pulled a little you would be fined.
Maybe if you kept the ATF bottle in the truck they might buy the story?
Then again in all the years I owned a diesel , 16, and the last 10 years driving with a CDL 18 wheeler not once was the fuel checked and I had a number of DOT inspection when you haul 10K gallons of LP and 26 tons of cement.
Dont sweat the color
Dave ----

 

Oh you are a lot braver than me to use that oil in a atuo transmission.
I dont know if I would even use it in my John Deere Garden tractor with Hydro Static transmission.
Ruin either one and you are taking some $$$ to fix but you do have the TH400 to drop in.
Dave ----

 

Well, at least I'm tinkering with my Bullnose truck today instead of playing video games or being lazy.

Have you ever seen this before? The skid plate under my rear fuel tank is 2 pieces. I think the previous owner did an R/R on the rear tank. It looks newer than my side tank did.




The front of the skid plate is down.

 

Well you got me with lazy
I did use the truck for it's weekly trash run this morning
Thru I used it in the rain to get 160# of salt for the water softener and to get a battery for My Durango retuned the core at the same time.

There was a cruise I was thinking of going to today and decided not to. Small parking area at a bar, I dont drink, so felt it best to stay home.
This way I did not have to crate the dogs.

My trucks did not have a skid plate so I cant say if that is right or not but as a guess not factory.
I should say the parts truck did not for either side or rear tank.
Is yours a 4x4 as I can see skid plates on the under side. Stupid question as I see in your sig it is
Dave ----

 

Yeah, she's a 4x4 with TTB suspension up front. I got the tank out. It wasn't as difficult as the side tank, but I see why folks recommend lifting the bed to R/R the tanks.

When I removed the passenger's side skid plate the tank was loose. I tried to let it down slowly with my floor jack but of course it's ON or OFF.

There was only about 2 gallons of old diesel in it. I moved the tank around by hand. I had to separate the fuel filler neck with the tank 1/2 way removed.

I peered inside the tank with a flashlight. I think there are remnants of the shower head in there. No big deal. I'm going to use compression fittings and strainer socks that I linked earlier.




I had used 19" of the blue 1/2" PEX for the side tank vent. I suppose I will for the rear too, I think it needs to be cut to 21". I tried to search for the thread that covered using PEX as a replacement vent hose. Here's one I found on OBs, but it's not the one I remember.

https://www.oilburners.net/threads/h...l.37382/page-2

Interestingly, there are 2 straps above the tank, but there were none below the tank securing it.

There was a skid plate below the side tank too. I never reinstalled it since my fuel gauge never worked. I suppose I should install it now since I want the fuel system to be 100%, or at least as close as I can get with an old injection pump and rebuilt injectors. 🤔

 

Yes the rear tanks do have straps at the top as the tank does not touch the bed.
Now I dont know about the skid plate tanks but my non-plate tank had straps at the bottom also.
I have seen the plastic tanks need the skid plate or when full they sag
Dave ----

 

My rear tank is skid plates supported. One is wider than the other. Take the wide one off first. Then your jack can support the tank while getting the skinnier one off.

If replacing the rear pay attention to the sump dimension as new aftermarket tanks changed the sump and won't fit with skid plate support. I had to go MTS plastic rear to find a fit. They are molded from an OEM tank.

 

Thanks for the advice.

I plan to reuse the rear tank. I got front and rear fuel senders on Amazon (part numbers earlier). I just hope the imported fuel senders read decently (they got to be better than 39 year old OE senders). I'll extend them with 3/8" fuel line and compression fittings. Hopefully the aftermarket fuel strainer socks I ordered fit well too. If not, I'll have the 2 spare mini-strainers from the old fuel senders I can use and I'll just send the strainer socks back through Amazon.

IMHO it's not worthwhile to try a replacement shower head. As I said, I put one in the tank a few years ago when I tried to convert a gasoline sending unit and it already fell apart.

 

Good news! The fuel in my tanks isn't ATF red. Disregard the earlier pic. Here's the auxiliary fuel filter I just removed from my Bullnose truck.



Looks like diesel to me!

I did have it mounted on the inside of the driver's fender where the tire iron and jack are stored. I never got the tire iron and jack when I bought the truck. In this pic there are 6 AN fittings IN and OUT. I got some 3/8" hose barbs to use instead. I just don't know if I'll leave it on the inside of the driver's fender or move it down below the truck. On the inside of the driver's fender it's sort of a PITA to reach.

The diesel I extracted from the side tank was ATF red in the earlier pic because I had used my vacuum extractor to remove the ATF from the pan of my 96 Oldsmobile 98 before I had to scrap it.

Sort of a relief. Now I guess I might just use that J20C hydraulic fluid for the ol' ATF trick in my Bullnose truck instead of in the TH400 of my 71 98. 🤔

 

Hope I am not too late but you can test the senders before they get installed with an ohm meter.
I am guessing both tanks will be empty and if so what I did was befe I added any fuel I turned on the key to see where the gauge needle sits on both tanks.
I then added 5 gallons to each tank and checked the needle again on both tanks.
The needle came up to the first line at empty. This way I know what the needle set at the empty lien I still got 5 gallons of gas left in the tanks.
Dave ----

 

I had a TH350 in a Chevy half ton. Dexron II was the spec'd fluid. I think I'd stick with the proper fluid as the TH transmissions are awesome.

 

I haven't put the fuel senders in yet. I just got the rear tank sender yesterday evening. I'll post pics of them modified before I reinstall them. I don't think I would check them for accuracy the way Dave mentioned, but I definitely want to test that new side tank sender before I install it. The goal is to have an operable fuel gauge for both tanks. Now whether or not that gauge is accurate is another matter.

 

100% frustrated!

• Ground the fuel sending unit signal connector at the back and the gauge sweeps to full.
• Ground the fuel sending unit signal connector at the front and nothing.
• Front fuel sending unit ground connector has good continuity to the frame.
• Front fuel sending unit connector signal wire has good continuity to blue/yellow going into the FSV.
• The FSV operates properly with the switch on the dash.

This means I should have an OPEN in the front fuel sending unit signal wire, correct? Plus, it should be between the FSV and the fuel gauge. I think...

What is this connector? It says Essex M-10505. Is it for my rear tail lights? That's the only connector in front of the FSV, besides a bundle of wires that goes to my transmission.



Disregard the steel fuel line to rubber hose. That is going to be removed.

Help!

 

This is the diesel in your signature? Thanks for that. Your problem with the sending unit points to the FSV. The fuel switching valve is what electrically switches the fuel gauge from the back to the front sending unit. Since one of them works, we know the gauge, the wire from the FSV to the gauge, and the wire to the working sending unit are good. The one that doesn't work, you are correct, it can be the wire from the non-working sending unit to the FSV. But my bet is the FSV electrical switch inside has failed.

If you want to do another test, switch the dash switch to the non-working tank. You should hear the FSV make a thunk noise. With it in that mode, take your grounding wire and try to back probe the wire on the FSV that goes to the non working tank. If it still doesn't work, I think that confirms it's the FSV is faulty.

 

^^^THIS^^^

I back probed the FSV for the side tank (blue/yellow) to ground and nothing. The blue/yellow wire has continuity from the FSV to the fuel sending unit connector.

The rear tank fuel sending connector (yellow/blue) sweeps the gauge to full when I ground the connector and the FSV.

I replaced the FSV in 2018 with a U7001 AC Delco valve I bought from Amazon. I checked and I don't have the OE valve in any of my parts bins. I guess it's time to get a new U7001 FSV. 🤔

Thanks for the advice in trouble shooting.

BTW, I did use an ohm meter like Dave mentioned and sweeped both of the fuel sending units. More updates to come.