Back half of fuel system overhaul

[gatorman21218]

So my fuel tanks are slowly driving me mad. I caint take it much longer. heres the problems:

1. Both fuel tanks have a fill rate of roughly the speed of smell. All I ask is to fill up once without it clicking off on me.

2. Both tanks cannot suck the bottom 1/4 tank out.

3. the front tanks reads empty all the time and the rear gauge reads about 150% full for half the tank and then drops like a rock to 1/4 tank when empty.

So I want to fix my filler necks and rollover valves, fix the pickups and replace all the fuel hose.

I also want to install Aftermarket gauges with aftermarket sensors.

I also want to replace my FSV with the manual kind.

Lastly I am going to take the bed off and fix all the rust on the crossbracing, and add ports in the bed to make the tanks easy access in the future.

Heck I might even get the LMC 28 gallon rear while I'm at it.

Thoughts on this project? Ill have lots more questions when I get a good long weekend to do it, but for now I am just going to assemble parts

 

[Diesel JD]

Hey Jim. Your problem is caused by the fuel tank sending units. They are the 87 and newer "new style" ford sender so any sender you get from JC Whitney or egauges that is in the 33-240 ohm range is the right range I think. The thing I don't remember and others here will correct me if I'm wrong about that range I hope, is whether 33 is empty or full. I have a sender here you can use for your project if you would like, it's yours for the cost of shipping. In any case you'd have to gut the aftermarket sender for its electronics and graft them onto your Ford unit. Depending on if the aftermarket sender follows the Ford unit exactly or is it's inverse you might or might not have to turn the sender and lever arm around. The other option is to cut a new hole in the fuel tank to fit the universal sending unit. Midnight Rider is the truly correct person to ask about this since he actually did the swap from the factory to a universal JC Whitney sender. Only problem is his info may not be 100% applicable since he used Felro86's procedure for an 80-86 unit and those units have a different ohm range. 10-78 IIRC. Anyway I can help you on the manual FSV. I have them installed, but currently don't have gauges or a second tank. The path is there though and I could have that second tank hooked up in an hour or two max. For two tanks you need 2 manual 3 way valves, one for the supply side and one for the return side. If a large auxillary tank PLUS the two stockers even might be in your future go ahead and get the two 4-way valves. At RLDSL's recommendation I got mine from First Choice Marine. Nice looking valves. I never figured out how to set them up to operate from inside the cab so when I plumb in a 2nd fuel tank I guess I'm going to be crawling under and operating them manually for the time being. For now I just have an appropriate pipe plug where the supply and return lines for tank #2 would be. As for the running out at 1/4 tank most here would tell you to just ditch the broken off foot/showerhead attachment and use a length of fuel hose. I think it is 5/16 but it might be 3/8" either way "fishmouth" it, making sure you don't make it too long, it needs to be very close to touching the bottom of your fuel tank but if it is too long you won't be able to get the lock ring sealed. This is a great place to use AN or Viton or fuel injection rated hose, not the cheap stuff since I don't imagine this is something you want to do every couple of years as the ULSD or your own fuel cocktails eat the cheap hose away.

 

[hesutton]

I modified my filler necks on the F250. The neck was gutted with the appropriate sized hole saw. The rollover valve was removed and a 7/8 piece of copper pipe was put in it's place to vent the system. Support brackets were made to hold the pipe so it wouldn't bounce around and out of the top of the tanks. A new vent was sodered into the side of the filler necks where the small stock vent tube went. I use 1 inch hose from the copper tube tank vent up the the filler neck vent. Canisters were made to hold the rollover valves. Quarter inch hose connects a nipple on the copper pipe to the rollover valve.

I have a ton of photos and measurements on the matter, but just haven't posted it all up yet. Here are a few photos below.

I can use the big nozzle at truck stops and fill an empty tank in less than 60 seconds and not spill a drop.

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The crew cab has Transfer Flow fillernecks in it and they don't function nearly as well as the home made stuff on the F250. But, they are better than stock.

I wish I could help you out with the senders, but I just bought new ones for the F250 when I was doing that project. I lost the stupid fuel pickup shower head thingies within three months. I pulled the senders and put an appropriate length of fuel hose with a inverted "V" cut in both sides of the hose so it wouldn't suck on the bottom of the tank. I've had no problems since.

Heath

 

[gatorman21218]

Yeah JD what I was thinking was to fix the old sending unit to work correctly, and then cut another hole to put in an aftermarket float that fed my gauges. I would have two separate gauges, thus I will be able to see both tank levels at the same time.

 

[snaponprofile]

Any update on this. My front gauge is now reading Empty while it is half full. It doesn't peg. it just slowly goes to E. I was wondering if this is a float issue most likely?

I plan on pulling my bed in the weeks to come so I will see what the issue is.

 

[icanfixall]

The front tank sending unit can be removed without pulling the bed or dropping the tank. But the rear tank is terrible to drop or pull the bed. Problem is any fuel left in the tank will throw it of balance when you drop it. A half tank can mean it weighsan extra 70 lbs and when it moves its tuff to support.

 

[banshee4599]

just fixed my front tank reading empty issue yesterday, turns out my float had a small hole in it and was sinking, took it all out and replaced the float and what do ya know it all works now. worth a shot to take a look at your float.

 

[smokin150]

when ya get a chance can ya post more pics of the mods, cause like gatorman21218 and prob alot more ppl on here, ive grown tired of the 45 min it takes to fill both tanks. i gotta drop my rear tank and drain it cause i lent the truck out and someone put gasoline in it, luckly they didnt get the front tank too. i figure this mod should be easy with the rear tank down

 

[gatorman21218]

I havent done anything on the sending units and gauges, but I did fix the front tank. I cut the inner hose as far up as I could. I installed a 45 degree exhaust elbow (2 inch IIRC) where the hose was kinked. I also removed the rollover valve and installed brass NPT bushing and a hose barb. I believe its 3/4 NPT that fits. Its a ***** to get that to screw into the rubber grommet but it can be done. I then ran some heater hose up to the highest point I could and then let it hang down a little. It will spray out a little fuel when shes full, but its a small price I pay for being able to fill up at max pumping speed.

 

[freebird01]

so its safe to say the 87+ truvks have the 240-33ohm unit....the couple of websites i came across seem to have the 87-89 listed the same as an 80-86...70-10ohm

 

[Diesel JD]

Freebird your thinking is correct I'm pretty sure. Some of these parts places are full of bad info.