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Discussion Starter · #1 ·
Hey guys, I have a deleted LBZ and I just installed an Airdog 150gph lift pump along with a Beans sump and it absolutely destroyed my mpg. Before i was averaging around 19mpg and now im getting about 6mpg. No leaks under the truck and cant figure it out. Anyone know why this could happen?
 

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Did you hand calculate the mpg or just reading the dic?

For the dic to calculate the mpg, it has to read the fuel going up stream and the amount going back on return side. If one of those sensors is messed up the calculations are wrong. Since you increased the supply side fuel pressure that may be it.
 

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You’ve got other problems.


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Absolutely sure no fuel leaks?
 

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Discussion Starter · #5 ·
Did you hand calculate the mpg or just reading the dic?

For the dic to calculate the mpg, it has to read the fuel going up stream and the amount going back on return side. If one of those sensors is messed up the calculations are wrong. Since you increased the supply side fuel pressure that may be it.
Did you hand calculate the mpg or just reading the dic?

For the dic to calculate the mpg, it has to read the fuel going up stream and the amount going back on return side. If one of those sensors is messed up the calculations are wrong. Since you increased the supply side fuel pressure that may be it.
So the computer is saying im getting the same mpg as before but hand calculated im getting around 6. I filled up tuesday and 2 days later i ran through 16 gallons and only went about 80 miles. Everything was fine before the lift pump. I do puff more black smoke than usual so im not sure if if the pressure of the lift pump is too much or what.
 

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Lots of complaints where the FASS 150 had been installed. I can't say that the FASS 150 was the source of the problems from personal knowledge, but there are lots of complaints.
 

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I have had that same pump on mine for years and it didn't have any effect on my fuel mileage.
 

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2017, 2500HD, LTZ, front guard, Duraflap mudguards, Leer bed topper
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Pressure regulators can fail. If the pressure is now higher than the regulator can control, could over fuel...

Diesel doesn’t just disappear.. is your oil level increasing?

to really know your MPG, fill, drive, refill. Is it possible there is a varmit pulling fuel out of your tank? It happens.
 
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