New member, fuel mileage question.

[garywj]

Hi there, I just purchased a 1992 Dodge w-250, 5.9, inter-cooled, 199,000 miles. The truck starts great, only a little puff of black smoke, seems to have plenty of power. I have had no problems with it so far. My question is: what kind of fuel mileage do you guys get with yours? I drove mine for the first tank unloaded, mixed city and country driving (55 to 60) and got 15.1 mpg. Is this normal or do I need to be looking for a problem? Also, if I wanted to increase power output to about 500 ft lbs, what would you suggest I do? The engine is completely stock at this point.

[cummins king]

sounds almost about right some guys get close to 20mpg, start by adjusting the fuel screw and suff, sust spend a bit of time on here looking at post and you will find everything you need to know

[ford69557ci]

i get 22-24 if i keep the driving normal. I think my truck got around 16 when i first got it but every mod I do seems to improve the mileage

[cummins king]

thats the way diesels work after you can keep your foot out of it

[garywj]

Sounds like mine is pretty normal. I think I will just adjust the pump, perhaps some new injectors, and change the exhaust. I don't want to kill the tranny,.....yet! Have you guys heard of a problem with the 1st gen cummins called the "killer dowel pin" problem? I saw an advertisement for a fix, Is it worth it?

[ford69557ci]

if you want to have piece of mind i would do it its cheap and really doesnt take that long to do. some of them can fall out and never cause damage but some can almost junk and engine.

[PToombs]

When you have the front cover off, remove and loctite the case bolts. They are near the cam. These are more of a problem on the 1st gens than the dowel pin. Do it now and don't worry any more about it. If a bolt comes out it's as ugly as the KDP.

[JQmile]

Hmmm. Mileage seems low. weight? Big tires? 2wd or 4wd? My 2wd gets about 18-20mpg, and that's with a no-overdrive 727 screaming along at about 70mph.

[ford69557ci]

a w is a 4x4 and compared to all of my friends trucks the non ic trucks seem to do a little better on mileage even though we have larger sticks from the factory???

[garywj]

Thanks for your input, I think the rear gears are 4.10's, im running 33 inch tires. I didn't notice till yesterday that the front hubs were in the locked position. I unlocked them so now the mileage might go up some. Also, my local cummins shop told me to get the valves adjusted and de-carbonize the injectors. They said these steps were commonly overlooked on the early trucks.

[garywj]

So, how do I do the valve adjust, and how do you clean or de-carbonize the injectors? What else can I do? sorry for all the questions....my first diesel!

[SChandler]

There is a write up on the valve adjustment here: http://www.dodgeram.org/tech/dsl/valve_adj/12_valve.html. Also, get a factory service manual (not a Chiltons or Haynes). It will help a lot. As for the injectors, I think Cummins has a fuel additive that is designed to do that. I've never used it so I don't know if it does anything or not.

[PToombs]

Geno's Garage for a FSM. I was on there the other day, Factory Service Manuals are up to $99. Used to be 85.