Ok i gotta 92 d350 auto. 4.10gears. When i bought this unit a couple years ago it use to get 19mpg on the highway. Now it gets 12mpg runnin empty, or pullin. I've done the overhead and fuel filter.. Anybody got any ideas why i'm not getting fuel mileage.. Thanks

 

Forgot to mention the pump has been turned up about 3/4 turn, and the smoke valve( i guess thats what its called) turned bout the same. Also put a 12cm turbine housing

 

Set the injection pump rack adjustment back to the factory setting.

On the older Cummins Rams it is usually much better to take it to a Cummins engine authorized shop called a Powerstore, rather than a Dodge dealership, because it will be rare for a Dodge tech to have been around enough years to have gotten the early training 15 years ago.

On the early all-mechanical Cummins B I6 diesel most fuel economy drops are caused either by:
low injection pressure from a worn pump (expensive to fix),
by injection timing being off (cheap to fix)
or by severe overfueling due to owner fiddling with adjustments (cheap to fix).

You can find authorized Cummins Powerstores in the Yellow Pages of the phone book, or by sending an message to Cummins through their website.

http://www.cummins.com/cmi/content.j...menuIndex=none