Fuel not transferring between tanks on ProStar

[Waterloo]

Just stopped to grab some fuel and noticed my right, passenger side tank is still full. I called the dealer and my service guy told me the fuel sending unit more than likely failed... They have sold a few in the past few weeks. So, what do you all think? Fuel sending unit? I have the part number, 6128686C1, sells for $100. Anyone have experience with this?

[Rawze]

What about a bad splitter valve on the return?

[Brock]

When mine quit, it was one of the float guages was bad and not telling the system to transfer. I think if one tank drops 20% lower then the other, it tells the transfer pump to pump over.

Until I fixed it, I just took a 1" piece of wire and jumped the transfer pump fuse whenever I needed my drivers side topped up. Pop it in, drive for a hour then pull it out.

[Brock]

Now that I'm thinking...... I think I put the jumper wire on the transfer pump relay and tool out the fuse, I would put him the fuse back in when I wanted to transfer.

[Pro Star Cummins]

Right side is just for storage on pro star.
We had problems also wouldn't transfer over.
Replace left side sending unit in tank . We ended
Up replacing right side first then pump, did the jumper thing ,pain in ass to get to
Pump . Decided to replace it . Still had problem until we replaced left side
Unit. It fixed our fuel gauge issue also . Drain fuel from tanks
And replace straps if bad.

[Waterloo]

(02-27-2017 )Pro Star Cummins Wrote:  Right side is just for storage on pro star.
We had problems also wouldn't transfer over.
Replace left side sending unit in tank . We ended
Up replacing right side first then pump, did the jumper thing ,pain in ass to get to
Pump . Decided to replace it . Still had problem until we replaced left side
Unit. It fixed our fuel gauge issue also . Drain fuel from tanks
And replace straps if bad.

So, if I am reading correctly I need to replace the left side sending unit, not the right side, correct? Afraid to even ask, but where is the pump located? Is there a way to test the sending units? Or, I am thinking just get two and replace both... When one goes the other is soon to follow.

Oh, my fuel gauge is still working if that matters? If my fuel gauge is still working, would that be more telling as to which side has failed?

Also, to change the sending unit out, will I need to drain the fuel tanks? It looks like I will have to loosen the tank straps and turn the tanks to extract the sending unit, correct? Will I need to remove the fuel line when I do this? And if so, is there a special tool needed to remove the fuel line? Is there some goofy fastener on there that can only be removed with a speciality tool? Or is it a simple push pull fitting?

[Brock]

(02-28-2017 )Waterloo Wrote:  

(02-27-2017 )Pro Star Cummins Wrote:  Right side is just for storage on pro star.
We had problems also wouldn't transfer over.
Replace left side sending unit in tank . We ended
Up replacing right side first then pump, did the jumper thing ,pain in ass to get to
Pump . Decided to replace it . Still had problem until we replaced left side
Unit. It fixed our fuel gauge issue also . Drain fuel from tanks
And replace straps if bad.

So, if I am reading correctly I need to replace the left side sending unit, not the right side, correct? Afraid to even ask, but where is the pump located? Is there a way to test the sending units? Or, I am thinking just get two and replace both... When one goes the other is soon to follow.

Oh, my fuel gauge is still working if that matters? If my fuel gauge is still working, would that be more telling as to which side has failed?

Also, to change the sending unit out, will I need to drain the fuel tanks? It looks like I will have to loosen the tank straps and turn the tanks to extract the sending unit, correct? Will I need to remove the fuel line when I do this? And if so, is there a special tool needed to remove the fuel line? Is there some goofy fastener on there that can only be removed with a speciality tool? Or is it a simple push pull fitting?

To test the transfer pump, shut the truck off in a quiet area and us a jumper wire on the transfer pump relay to give power to both sides, listen for the transfer pump to start running. If the pump runs then you ruled that out.

Next, the fuel guage is ran by your driver's side tank so if your not having a fluctuating or inaccurate or dead fuel guage and the transfer pump is verified to work, that can only mean the passenger side tanks fuel float is bad.

Loosen the straps and rotate the tank to get them off, if you have full fairings like I do........ good luck with that crap shoot lol

[Pro Star Cummins]

The transfer pump is on top of transmission and hard to get to. to gain access
You need to remove shifter boot . Ours worked,but being it was so hard to get to we decided
To change at home instead of alongside of road. We had continuity tested both
Sending units and read ok. Reason we drained fuel from tanks was to make
It easier to rotate and we replaced fuel lines and fittings too. The tank straps
Were replaced too. One had broken and let tank drop against faring. We are going
To get rid of this truck and rebuild our old Pete. What a nightmare this truck
Is. Never ending problems .we replaced right side sending unit first and had same
Problem fuel would not transfer over. We did jumper pump trick . Final fix was left side
Sending unit . Hope this works for you. We're not professional mechanics ,just trying to
Muddle our way through.lol

[Waterloo]

Well if everything I am hearing is correct my left side (driver) sending unit is good, no fuel gauge issues.

The transfer pump, I can get to that through the boot? Right now I just want to test the pump. This jumper procedure is what has me stumped. Do I pull the relay in the main fuse panel and jump there? That is what I am assuming? Or, do I just feed 12 volts direct to the pump off a hot wire? I don't want to burn it up if it is not the issue.

As far as testing my fuel tank sending unit, how would I go about that? The tank is filled right up to the neck. Would I be able to get a reliable reading with my ohm meter with a full tank? I wish the hell I could just pull the damn thing out! Not that easy, as my right side tank doubles as a hydraulic fluid tank for my pump... And it is full.

Also, assuming again, if I can get the pump working, it will drain my passenger side tank, correct? It does not flow the other way if I understood correctly from Brock's post. Thanks guys