New fuel tank and sending unit weirdness (Questions)

Rembrant wrote

How much does the rear tank hold? Or, how much is it supposed to hold?

Consider these charts:

Steve - You have lots of good info, but I don't understand the layout of your stuff.  And while I may be the only one that understands the layout here, it does seem logical to me.

In this case the information from Ford's Master Parts Catalog is at Documentation/Fuel Systems/Fuel System Part #'s/Fuel Tanks.  And it should be easy for anyone to answer the question about fuel tank capacities.

Is it possible that fuel is being transferred from one tank to the other?

1986F150Six wrote

Is it possible that fuel is being transferred from one tank to the other?

Interesting question, David.  Ray and I saw that happening on his '86, but it had the electric fuel pumps and a return system and the valve was returning to the wrong tank.  However, Jim has a mechanical pump.....

Jim - Do you have a return?  As in the hot-fuel handling setup?  I didn't think the hot fuel handling system was used with a mechanical pump, but maybe you added the mechanical pump and left the hot-fuel system?

Nope Gary.

Pump on the timing case from day one.

My switch valve is good and no transfer or the front tank would overflow.

I just filled up, 17.12 gallons from dry in the rear.
I used to squeeze in almost 20 when full to the neck.

Something's definitely weird.

Jim, is the rear tank dented from striking something?

Nope, David.

Gary Lewis wrote

...I don't understand the layout of your stuff.

Are you talking about that chart in particular, or my SMN stuff in general?  Generally, it's pretty random.

The "chart" is just a page from the MPC.
Most of us understand how to read the ******* manual.  

Steve - That would explain why I haven't figure it out.  

Jim - Yes, what I posted is from the MPC.  Not sure what you mean.

If you're talking about what I posted, you're ******* wrong.  I don't have any ******* MPC, so I can't ******* post any ******* pages from one.  If you have a ******* MPC that you ******* understand how to read, maybe you should ******* post it all so that any*******one can ******* look through it.

What I posted came from a couple of ******* service manuals, which don't have ******* pages.

Gary Lewis wrote

That would explain why I haven't figure it out.

When I start a project on my truck or something similar, I usually start a new album on SMN for it.  Then I try to organize the pics so that anyone who wants to do something similar can follow along, and make other decisions based on the info I considered when I was choosing how to do my job.  So to find something about fuel tanks on my SMN pages, you'd start at my signature link, and scroll down the album list to find one that has something to do with fuel tanks, and browse that album.  If you didn't find it there, or if there was no album that looked promising, you could browse the General Purpose album, or the Diagrams album (depending on what you wanted to find).

Once inside an album, you can switch to a view that shows the captions, hit CTRL+F, and search up something that relates to what you're interested in.

Yeah, it takes a little effort, but there's a lot of info there that I've amassed over the decades, so it usually pays off.

Wow!

Man, calm down (please)
Take a deep breath and let it out slowly.

I'm not really sure what I said to set you off, but you definitely have a hair trigger today Steve.   🙏

Ok guys, this isn't in the vein of Family, Brotherhood, & Kindness.  Please stop.  Now.

Aaand, I'm unsubscribed.

I was hoping this thread might have some answers for me, but I'm gone...

I just typed my response, and then noticed how funny it would be if I copied his asterisks and inserted them strategically into what I had typed.   BTW Gary; I added a reply to you into that post.

Ok, back on track with Rembrant's original issues and "weirdness" with his new fuel tank and fuel sending unit. I think the issue has been resolved, but I'll have to wait now until I burn through a full tank of fuel. I have to apologize as I made a bunch of mods here and didn't take ANY pictures (like I normally do).

Below is what my new fuel sender looked like, exactly:



I did two things. See how the last bend in the float is less than 90 degrees? Maybe it's 75-80 degrees, right? I ended up bending that arm about the same distance beyond 90 degrees, so it is now maybe 100-105 degrees. The problem then was that the bottom travel point of the float was below the lowest point of the pickup tube (I also measured the pickup tube to be approximately 2" above the floor of the tank.).

I then bent the pickup tube down a little bit (Nicely, with a proper tubing bender), so now the pickup tube is about 1 1/4" above the floor of the tank. I'm OK with this.

So...I put 10 liters in the tank, or approx 2.5 gallons. With the fuel sender float arm bent down, I had it reading on "E" at this point. I drove the truck and had it running a bit, and burned probably a 1/4 gallon of fuel. When I filled it up, it took 53 liters, or 14 gallons, and the gauge went past the "F" mark.

VICTORY!!!

I was able to fill the tank with the gas nozzle on full speed, and when it clicked off, I had approximately 62 liters in the tank, or 16.5 gallons, which is exactly what Spectra Premium specs it at. So now, between FULL, and EMPTY (indicated) should be about 14 gallons, or exactly where I was prior to changing the tank and sending unit.

I'm pretty stoked about all this. It took quite a bit of trial and error, but I think it's OK now...or at the very least, far better than it was.

I'll report back after I burn off some fuel and see how the gauge behaves.

So...in conclusion...there are a couple things I learned here in dealing with aftermarket replacement part blues:

If you install an aftermarket sender, make sure you stroke the float arm to make sure the gauge travels from empty to full.

Even more important, make sure you place the new sender next to the old sender and compare the float heights and float travel. I didn't do this previously, but wish I had.

That's all. Carry on. Peace & Axle Grease!

Cory

Well explained, Cory.  Even w/o the pics.  I understood.  And, I like the results as you won't run out when the gauge hits E.  

Gary Lewis wrote

Well explained, Cory.  Even w/o the pics.  I understood.  And, I like the results as you won't run out when the gauge hits E.  

Gary, the good news is that right now I actually know exactly how much fuel is in the tank. It will take me a few days to burn that fuel and see how the gauge reads, but I'll be reporting back with an update when I get there.

As you "drive the wheels off" before the snow flies the fuel level will certainly go down.  Let us know.  

Rembrant wrote

If you install an aftermarket sender, make sure you stroke the float arm to make sure the gauge travels from empty to full.
Even more important, make sure you place the new sender next to the old sender and compare the float heights and float travel.

That's a good practice, even with an original sender, or ANY other part.  If at all possible, test it before or during installation.