i have a 92 d350 auto diesel,4.10 gears. when i bought it years ago it got 19mpg and it now gets 12mpg loaded or empty. I've removed the muffler, installed 12cm turbine housing, turned pump up 3/4 turn. I've just readjusted the valves, new fuel filter and no better results. It runs plenty healthy, but my mileage just aint what it use to be. Any ideas???? Thanks

 

Tranny slippage?

 

your putting more power to the ground, that equals more fuel burned to achieve that power, the new ULSD has a lower cetane rating than the LSD of before. also since you have a 92 I would check all your fuel lines and make sure none are dry rotting and the seals on your VE pump are still good.

 

No tranny slippage!!! All the fuel lines are in good condition? The fuel mileage went to crap before i turned the pump up. Actually when droven on the highway now after the turnin of the fuel the fuel mileage was almost the same. ANY IDEAS

 

my 93 d250 ctd still rolls at 19mpg. have ya used any additives lately?

run the power service Diesel kleen for a while or mix Drews Brew .

since I started using power service, the engine is clean and blows very little black smoke, even with passin gear on the freeway.

 

yea i've run alot of lucas in it. It works real good in my big truck but it seemed to be the same if not worse in my cummins!!!!!!!!

 

What's drews brew???????

 

here ya go, https://dodgeforum.com/m_578939/tm.htm