2014pinnacle Posted January 20, 2023 Share Posted January 20, 2023 Hi guys I have a 2016 pinnacle Mp8 engine my fuel tanks aren’t balancing passanger side tank gets sucked dry and drivers side is full. I have replaced the fuel tank vents how do these tanks balance themselves? What else should I be looking at? Quote Link to comment https://www.bigmacktrucks.com/topic/72365-fuel-tanks-not-balancing/ Share on other sites More sharing options...
tjc transport Posted January 20, 2023 Share Posted January 20, 2023 Look for a valve on the crossover line off the bottom of the tanks. One of them is turned off, most likely on the driver side tank. Quote when you are up to your armpits in alligators, it is hard to remember you only came in to drain the swamp.. Link to comment https://www.bigmacktrucks.com/topic/72365-fuel-tanks-not-balancing/#findComment-523226 Share on other sites More sharing options...
upsman Posted January 20, 2023 Share Posted January 20, 2023 No crossover on those usually. Quote Link to comment https://www.bigmacktrucks.com/topic/72365-fuel-tanks-not-balancing/#findComment-523228 Share on other sites More sharing options...
tjc transport Posted January 20, 2023 Share Posted January 20, 2023 If there is no crossover line, than how does fuel get drawn from both tanks? If there is no crossover, than duel will only be drawn from one tank like he is experiencing. Unless there is a tank selector switch. 1 Quote when you are up to your armpits in alligators, it is hard to remember you only came in to drain the swamp.. Link to comment https://www.bigmacktrucks.com/topic/72365-fuel-tanks-not-balancing/#findComment-523230 Share on other sites More sharing options...
Popular Post upsman Posted January 20, 2023 Popular Post Share Posted January 20, 2023 Draws and returns pull out of top of tank and meet at a tee under cab. Balancing valve there maybe messed up and diverting return to one tank only. 3 Quote Link to comment https://www.bigmacktrucks.com/topic/72365-fuel-tanks-not-balancing/#findComment-523234 Share on other sites More sharing options...
Joey Mack Posted January 20, 2023 Share Posted January 20, 2023 Yes to the valve under the cab. The hard plastic lines can develope an air leak. The crimp can loosen.. also, check the tank vent tubes and clean fuel caps if they are vented.. The dual suck dual return set up is crap.. I think freightliner had a better setup and they had shut off valves.. jojo 1 Quote Link to comment https://www.bigmacktrucks.com/topic/72365-fuel-tanks-not-balancing/#findComment-523269 Share on other sites More sharing options...
Hayseed Posted January 20, 2023 Share Posted January 20, 2023 16 minutes ago, Joey Mack said: The dual suck dual return set up is crap.. ^^^ Spot on Joey, I 've had a lot of Trouble with them.. Our roads have a very high Camber/Crown & the return fuel take the path of least resistance & all the return fuel ends up in the curb side Tank. Because fuel is drawn from both tanks but only returned to one.. I remove the return line to the curb side tank, & problem solved.. 1 Quote "Be who you are and say what you feel...Because those that matter...don't mind...And those that mind....don't matter." - Link to comment https://www.bigmacktrucks.com/topic/72365-fuel-tanks-not-balancing/#findComment-523274 Share on other sites More sharing options...
fjh Posted January 20, 2023 Share Posted January 20, 2023 2 hours ago, Hayseed said: ^^^ Spot on Joey, I 've had a lot of Trouble with them.. Our roads have a very high Camber/Crown & the return fuel take the path of least resistance & all the return fuel ends up in the curb side Tank. Because fuel is drawn from both tanks but only returned to one.. I remove the return line to the curb side tank, & problem solved.. Yup pain in the ass big time also check the vent filter on the tank! 2 Quote Link to comment https://www.bigmacktrucks.com/topic/72365-fuel-tanks-not-balancing/#findComment-523292 Share on other sites More sharing options...
2014pinnacle Posted January 21, 2023 Author Share Posted January 21, 2023 Ok thanks so where is this diverted valve located under the truck do you have any pictures of it? Is it an expensive part? Both fuel tank vents are brand new I have non vented caps should would vented fuel caps make any improvement? Today I put 269 litres of fuel in the passages side tank and 200 in the drivers side so I guess the diverted is working abit? Quote Link to comment https://www.bigmacktrucks.com/topic/72365-fuel-tanks-not-balancing/#findComment-523363 Share on other sites More sharing options...
Joey Mack Posted January 21, 2023 Share Posted January 21, 2023 its under the sleeper, follow the fuel tank lines to the center of the truck, they join at the valve.. 2 for the suck side and 2 for the return side. Quote Link to comment https://www.bigmacktrucks.com/topic/72365-fuel-tanks-not-balancing/#findComment-523364 Share on other sites More sharing options...
2014pinnacle Posted January 21, 2023 Author Share Posted January 21, 2023 When I replace this valve when the lines are off is it going to drain the tanks? Should I wait till the tanks are at about 1/2? Quote Link to comment https://www.bigmacktrucks.com/topic/72365-fuel-tanks-not-balancing/#findComment-523365 Share on other sites More sharing options...
Joey Mack Posted January 21, 2023 Share Posted January 21, 2023 no, the lines are above the fuel level.. if you let them drop below the level, then yes a syphoning will happen.. they should be too stiff to drop on their own.. Quote Link to comment https://www.bigmacktrucks.com/topic/72365-fuel-tanks-not-balancing/#findComment-523366 Share on other sites More sharing options...
Popular Post mechohaulic Posted January 21, 2023 Popular Post Share Posted January 21, 2023 18 hours ago, tjc transport said: If there is no crossover line, than how does fuel get drawn from both tanks? If there is no crossover, than duel will only be drawn from one tank like he is experiencing. Unless there is a tank selector switch. lower cross over line ; was in the good days (old school). too many ripped off cross over lines from road debris, resulting in fuel spills/leaks . as with most "improvements" results were, are a pain in a-s 3 Quote Link to comment https://www.bigmacktrucks.com/topic/72365-fuel-tanks-not-balancing/#findComment-523370 Share on other sites More sharing options...
Popular Post Onyx610 Posted January 21, 2023 Popular Post Share Posted January 21, 2023 1 hour ago, mechohaulic said: lower cross over line ; was in the good days (old school). too many ripped off cross over lines from road debris, resulting in fuel spills/leaks . as with most "improvements" results were, are a pain in a-s Yup, but either you get over it or buy something older. Can’t stop progress… 1 2 1 Quote Link to comment https://www.bigmacktrucks.com/topic/72365-fuel-tanks-not-balancing/#findComment-523374 Share on other sites More sharing options...
fjh Posted January 22, 2023 Share Posted January 22, 2023 21 hours ago, Onyx610 said: Yup, but either you get over it or buy something older. Can’t stop progress… So true! Might have to by a Pete ! Oh wait they are using these too!🤨 1 Quote Link to comment https://www.bigmacktrucks.com/topic/72365-fuel-tanks-not-balancing/#findComment-523507 Share on other sites More sharing options...
Joey Mack Posted January 22, 2023 Share Posted January 22, 2023 it's too bad fuel tanks dont have side plugs in them anymore... I would rather have a cross over.. I think the key is tightly crimped fuel lines at the valve that they pull through... I forgot the name of it.. Quote Link to comment https://www.bigmacktrucks.com/topic/72365-fuel-tanks-not-balancing/#findComment-523509 Share on other sites More sharing options...
Mark T Posted January 22, 2023 Share Posted January 22, 2023 I think one of the reasons they split like that has something to do with cooling off the fuel too. Quote Link to comment https://www.bigmacktrucks.com/topic/72365-fuel-tanks-not-balancing/#findComment-523514 Share on other sites More sharing options...
Joey Mack Posted January 22, 2023 Share Posted January 22, 2023 🤔 Quote Link to comment https://www.bigmacktrucks.com/topic/72365-fuel-tanks-not-balancing/#findComment-523515 Share on other sites More sharing options...
Mark T Posted January 22, 2023 Share Posted January 22, 2023 36 minutes ago, Joey Mack said: 🤔 🧐 1 Quote Link to comment https://www.bigmacktrucks.com/topic/72365-fuel-tanks-not-balancing/#findComment-523519 Share on other sites More sharing options...
fjh Posted January 22, 2023 Share Posted January 22, 2023 11 hours ago, Joey Mack said: it's too bad fuel tanks dont have side plugs in them anymore... I would rather have a cross over.. I think the key is tightly crimped fuel lines at the valve that they pull through... I forgot the name of it.. Ya Joe That baffles me what goes thou the minds of these design guys there is no thought put into having to service any thing on these new rigs!! Everything has to be done the hard way can't put to use Gravity unless you use you Mexican credit card Or a spike! 😡 one good thing thou you don't have to replace the electric primer pump on the truck it don't got one! 😁 1 Quote Link to comment https://www.bigmacktrucks.com/topic/72365-fuel-tanks-not-balancing/#findComment-523533 Share on other sites More sharing options...
tjc transport Posted January 22, 2023 Share Posted January 22, 2023 gravity transfer worked just fine for what, 80-100 years? but the engimaneers read that bulletin about "if it aint broke fix it until it is".....and did. Quote when you are up to your armpits in alligators, it is hard to remember you only came in to drain the swamp.. Link to comment https://www.bigmacktrucks.com/topic/72365-fuel-tanks-not-balancing/#findComment-523541 Share on other sites More sharing options...
mowerman Posted January 22, 2023 Share Posted January 22, 2023 I didn’t even know they got rid of them until recently since my 680 Kenworth had the same problem a few months ago they fixed it in one day. I don’t know what they did to it. And there and didn’t see any new parts…. Bob Quote Link to comment https://www.bigmacktrucks.com/topic/72365-fuel-tanks-not-balancing/#findComment-523543 Share on other sites More sharing options...
Onyx610 Posted January 22, 2023 Share Posted January 22, 2023 The return flow splitter was to eliminate the crossover line between the fuel tanks in over the road vehicles. It is intended to equally divide the returned fuel from the engine into two streams. One of which would be routed to each fuel tank The object of dividing the returning fuel is to maintain equal fuel levels in both fuel tanks. Quote Link to comment https://www.bigmacktrucks.com/topic/72365-fuel-tanks-not-balancing/#findComment-523544 Share on other sites More sharing options...
fjh Posted January 22, 2023 Share Posted January 22, 2023 1 hour ago, Onyx610 said: The return flow splitter was to eliminate the crossover line between the fuel tanks in over the road vehicles. It is intended to equally divide the returned fuel from the engine into two streams. One of which would be routed to each fuel tank The object of dividing the returning fuel is to maintain equal fuel levels in both fuel tanks. I also believe that they moved the fuel pickup and return to the mid tank location for that reason also! When this setup came out on the top mounted in and out there was a lot of grief with it! just my opinion 1 Quote Link to comment https://www.bigmacktrucks.com/topic/72365-fuel-tanks-not-balancing/#findComment-523553 Share on other sites More sharing options...
mowerman Posted January 22, 2023 Share Posted January 22, 2023 On 1/20/2023 at 7:50 PM, Onyx610 said: Yup, but either you get over it or buy something older. Can’t stop progress… we would all be happier with driving steel dash R models ,,,but were all stuck in slope nose plastic junk that wont stay running...bob 1 Quote Link to comment https://www.bigmacktrucks.com/topic/72365-fuel-tanks-not-balancing/#findComment-523555 Share on other sites More sharing options...
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