Hello all! I have done a good bit of searching, but can't find the answer I need. For some time I have had the common problem of running out of fuel at a quarter on both tanks. Then in the last couple of months, the front tanks starves and kills the engine no matter what level. I pulled the bed off and expected to find the entire stem rotted off. But just that bottom plastic piece is missing.


How can I trouble shoot the sending unit? It appears fine except for the bottom cone. All I could find in the tank were the screen and small plastic pieces. Is it possible it sucked up one of these pieces? From what I am reading, it is almost impossible to find the front sending unit. Any help would be appreciated!

 

check the fuel selector valve, make sure its is actually selecting. it is very possible that it sucked up some of the old broken pieces. I have not experienced this myself but have read the stories doing general research learning about my own truck.

 

I thought about the switch. But when I switch to the front tank it is doing something, otherwise it would not starve. Plus the fuel gauge responds and shows the front tank as full. But I guess you are actually talking about a different part. Where is this valve?

 

It is mounted on the driver side frame rail, I have a crew cab, YMMV. mine is approx between the front/rear doors on the frame. If it does show the fuel level my best assumption would be clogged line. But as said previously, i'm not an expert . If it was right in front of me, guaranteed fix.

 

the sending unit for gauge is not a indicator, that it fully switched tanks, chunks of crap can get stuck in the valve.

 

i had this problem with the rear tank of my 87 F350.
it was the FSV that was clogged.
i opted to delete the front tank completely.
running a 89 F350 gasser 33 gal rear tank
no more FSV to deal with!
the sending units are obsolete for diesels. but gasser sending units work!
you just have to delete the fuel pump and extend the pick up.
a little re-wiring, and youre good

 

Mine runs out after 12 gallons. I think the front tank is supposed to be 19 gallons, so if it was clogged like yours it wouldn't work at all. From reading on the other posts it looks like the pickup tube can get stuck or float at a certain level. When I was working on VW Vanagons the problem with the tanks was always the wierd ventilation system, seals wearing out, and rust getting on top of the U-shaped tank that the coolant tubes had to run on top of. Now its screwy senders, floating pick-up tubes and tank selector switches, oh my! Seems like a good idea to get one massive tank, but two tanks is just cool! All the guys always go "WWhooahh dude you have TWO tanks!! Badass!!!"

 

and the guys that converted to one tank say
"yea i remember having issues, now i dont have any!"

 

Yeah I agree. The less moving parts and less components, the better.
Could we fit more than one 33 gallon? or maybe a 19 and a 33? Just curious.

 

19 gal front.
and they make a 38 gal rear.
my 33 gal came out of a 89 F350 i had for parts.
so i had the shroud and everything, altho i had to space it to fit.

 

I think that is my next step to check the valve. I suppose it could have clogged in the crook of the pickup stem.

 

I did the fix that everyone else has of buying the fuel contact hose from Napa to extend the stem on down. What I would like to do is put some sort of filter over the end of the hose. I am not sure what to get that would stand up to the diesel. Some sort of brass screen?

 

The fix everyone else has? what size hose do you have to buy and how do you install it? I tried searching, but maybe I'm using the wrong words.

 

I used 3/8 Id fuel contact hose from Napa. They actually called it something different. Following the lead of others that have posted, I cut notches at the bottom of the hose to prevent it suctioning to the bottom of the tank. The total extension you need is 3 1/2 inches including the 1 inch that slips up on the stem. You then clamp it.

Before I put it back together, I want to put a filter over the end. I am thinking of stainless steel mesh. I will post a picture of that when I figure it out.

 

So as an update, I took the selector valve off, drilled the rivets out and am going to clean it up. Then I got to thinking about the vents on the tank. If they are clogged, would that starve the output? I don't know the answer to that, but I took the PVC valve out and it and the line are pretty clogged. So I am replacing the line and cleaning everything else. Hopefully it will run once I get it together!