Fuel Not drawing from Passenger Side Tank

The splitter valve or equalizer block whichever you want to call it, has 2 flappers inside it. Take one apart and you will see. If it hangs up then it will cause this problem. If you have replaced fuel lines and did not get both pick up lines the same size in length it will also cause this problem. If one of the return lines is swollen inside it will also cause this.

Get 2 empty jugs and disconnect return lines, put each one in a jug and start the truck and monitor the return flow, they should both be the same. Then if that is okay, shut the truck off, shut both valves off on the bottom of the tanks, disconnect the feed lines then open each valve one at a time and take notice of the flow out of each valve, they should be the same. If they are not then something is in the tank stopping up the flow of fuel.

 

Having the same issue and have already replaced all fuel lines except the return lines. New fuel pump and check valve as well. Did find fitting on top of tank lose tonight though.

 

Yall ever fix the issue? Im having the same problem...

 

Seems like those problems are created with improper tank venting or blocked return lines.
Loose the fuel caps little bit and see if it is equalizing amount of fuel in both tanks, it will take time so be patient.
If vents are blocked, the return line cannot bring extra (not used) fuel back to this tank, so it is only sucking from it and return everything to another tank. We had this issue and it sucked air from passenger tank and truck died in the middle of the road. Driver opened driver side tank and it was halfway full, but pass side tank is almost dry(no fuel). Have to call for a fuel delivery and then we figure out the venting problem.
Stay away from the shops, keep those wheels moving!
Cheers, stay safe out there.

 

so i've been searching for an answer regarding this issue with the fuel not leveling in the tanks. I've got an 05 379 with an isx cummins in it. I've changed the fuel lines to and from the tanks. Done the return line spliter about 6 times cleaned the tanks changed the tank vents called peterbilt got no help from them so now i'm wondering if there is something i missed. would it help to put return line stand pipes in each tank and let the pressure equalize it? i don't want to put in cross over lines if i don't have to.

 

Have you find an answer for your issue? My 07 Pete 379 is also doing the same thing, the tanks were removed and cleaned, also both breathers cleaned, replaced basically all fuel lines including pressure lines around the engine and return lines to the tanks, replaced transfer pump, replaced both transfer valves, cleaned the fuel filter housing and replaced 2 o-rings on the plug there, replaced both filters but the truck is still only using the fuel from the passenger side. Already spent $3,300 at Peterbilt in Orlando, plus close to $2k in road services to start up the truck and move to another location. Right now my driver is filling the passenger side tank every 50-65 gallons to prevent the truck to shut down.

 

We are battling same problem on my Sons 2006 Peterbilt. Grrrrrrrr!!! New splitters, all new hoses, new vents. The only thing that seems to help is to flip up latches on fuel caps.

 

I'm looking for answers too.
However, I don't have valves on the bottom. Supply and return are on the top. No crossover either.
Vents seem to be open. Though, one is missing its hose. I'll fix that when I get home. At the moment , though. I'm confuzzeled

 

Seen it with Volvos lots when they get a plugged vent line on top. Check the vent.

 

Your fuel pick up line is plugged up.
Remove the section between the tank and splitter valve.
Have someone hold a rag on one side.
Blow out with air pressure.
Remove rag and check for debris.

The "splitter valve" is nothing more than a simple T
It allows fuel to be pulled from both tanks.
It has no moving or non-moving parts. Just a hollow T
They don't go bad. They can get plugged up with debris, which is easily cleaned out.
More than likely, something fell into your fuel tank, Bit of rag... Paper... A bug... Something....
Eventually it get sucked into the fuel line, and blocks it.
The reason the tank is staying full on that side is because the fuel return line is sending fuel back to both tanks, but not enough fuel is being pulled out of the tank.
Eventually, if line is not blown out, debris may completely plug up the line and since fuel is being returned to it... The tank would overflow.
This is the reason for the third small line on your tank... To relieve overflow to prevent the tank from rupture.
Very easy, beginner level fix. Don't need a shop.
Shut off valve at bottom of tank.
Remove fuel feed line, usually at bottom of tank.
(rare cases have a pick up line thru the top) if so, 4 small screws hold it in place. Remove follow same procedure.

Required tools.
Pliers, or screwdriver to take of 2 clamps.
Compressed air, and shop or car mechanic will probably blow it out for free.
Rag, to "catch" anything blown out of fuel line so you can see what was in it.
Bucket/pan to collect fuel in line.
Bucket/pan, open fuel valve on bottom of tank to see if more debris is waiting to be sucked out. Drain a little fuel until your sure nothing is in tank.
Beginners level.
Time: 1 hour max.
Tools: screwdriver, plyers, bucket, rag, compressed air

Anyone give a more complicated answer, chances are they are not overly familiar with fuel delivery at the starting point.