Rear Fuel Tank Issue

[dakotajeep]

Ok when I run the front tank the truck is fine. But when I run off the rear tank the at highway speed (ie high demand) the fuel filter light comes on and the engine runs rough and stalls out unless I switch it to the front tank.

I have no idea. I have put rubber fuel hose on both tanks due to the pickup tubes being broken.

My only thought is that somehow a piece of the pickup tube became lodged in the fuel line and is restricting flow.

Does that seem logical? Any other thoughts?

How do I remove the fuel line from the switch that moves between tanks? I have no idea how without screwing it up!!!!

I am going to work on the front tank rubber hose while I wait on responses.


Thanks
Thad

 

[91f2504x4]

Is it possible that the rubber pickup is either too close or touching the bottom of the tank? I had the one in my truck just too close to the bottom of the tank and it would run fine until I was running high throttle and then the light would come on.

 

[royzell]

How do I remove the fuel line from the switch that moves between tanks? I have no idea how without screwing it up!!!!

I just took the selector valve off a '91 parts truck. IIRC The hose was held by a 2 piece plastic clamp. Pry the top round part away from the hose about 1/4 inch, then I think you squeeze the 'legs' to remove the rest of the clamp.
'Hope that is correct and makes sense.

 

[91f2504x4]

I skipped right over that question when I tried to answer. The hoses come loose from the switch the same way that they come loose from the pick-up unit on the tank. Little plastic clips that pop up and then the hoses slide off.

 

[RLDSL]

You may have critters in the rear tank. I've run into that before after letting the truck sit for an extended time while rebuilding the engine. The rear tank got critters ( algae) and when I got it going again running off the rear tank would shut it down, switch back and everything fine. A healthy dose of Kill-em and a few filters took care of it. Not saying that's the problem, but one possibility.

 

[gandalf]

I seem to recall that there is a specified way to cut the rubber tube you use for a fuel pickup. You don't just cut it, as you would with a pair of scissors, giving the end cut a flat surface. With a flat cut it can conceivably get into a position against the bottom of the tank so that it blocks flow. It would be like sucking on a straw and blocking the end with your finger.

If memory serves me, you should cut a v shape, either inward or outward, at the end of the pickup tube, so that it cannot be blocked/plugged against the bottom of the tank.

What are the actual chances of that happening? I haven't got a clue. But I seem to recall somebody recommending this procedure in the past.

 

[dakotajeep]

Yeah, I cut a V in the end. I am fairly certian its not suctioning off the bottom of the tank. I would like to see a picture of what the factory pickup and sending unit look like.


THad

 

[91f2504x4]

I had cut a V in mine as well and it was still causing my problem, I just pulled the pick-up assembly back out and cut off a half inch of the rubber pick up and it has given me no problems since.

 

[dakotajeep]

I have come to the conclusion that it has to be pieces of the broken pickup tube that has become lodged in my fuel lines/fuel selector valve.

I just have to dig into it tomorrow and see.

I still cant figure out the fuel selector valve connections.....they are different. It not the normal fuel connection.

Thad

 

[91f2504x4]

I have come to the conclusion that it has to be pieces of the broken pickup tube that has become lodged in my fuel lines/fuel selector valve.

I just have to dig into it tomorrow and see.

I still cant figure out the fuel selector valve connections.....they are different. It not the normal fuel connection.

Thad

I had mine off just the other day and they were identical to the ones that were on top of the tank, maybe they changed something between my year and yours. The only thing was the lines are turned so that the little plastic clips where in the most incoveniant spot to get off. If it is the same as mine then your Supply lines should have white clips and your return lines should have black clips, unless mine were just different. I had to put a few new ones on mine because I broke some when I was taking the lines loose.

 

[dakotajeep]

I had Ford replace the selector in ND while I was home for Christmas, since I had quite a bit of trouble with it then. Now it just seems that it was malfunctioning due to pieces of a broken pickup tube......maybe.

Thad

I will take pictures tomorrow and post them....

 

[dakotajeep]

I ended up just putting a new FTSV on, using rubber fuel lines and hose clamps to connect it the tanks.

Seems to be working fine for the time being.

Thad

 

[Full Monte]

You might be sucking in air on the fuel line on that tank. That would do it.

 

[k_williams1982]

I would like to see a picture of what the factory pickup and sending unit look like. THad

Still need a pic? I have a set of front and rear sending units sitting in the garage with the pickup on them.

 

[dakotajeep]

kenneth

Absolutely, more so I want to the know how far down to have the rubber end ie a measurement. I want to have the end as far as possible to get as much fuel as possible out of each tank. I think I got the front one as far as it can go but the rear was harder for me.

And yeah, you can do it by brail but I want measurements and a pic!

Full monte

I figured out the problem. I was more so posting that I had figured out my problem. It wasn't getting air in the system it was restricted flow due to pieces of the "shower head" that had broken and found its way in the fuel lines and FTSV. But thanks for the suggestion.

Thad