MountainBen

I am still trying to refine my truck's running condition. I have a 1993 Dodge W-250 with the 12 valve, 5.9L Cummins. It has the 354 gear ratio and a Banks kit (not sure exactly what was changed from the original stock set up). I am driving grampa style and keeping the speed down around 1,800 rpm's on the highway, around 60-65mph. Turbo boost guage never sees much over 10psi if there ever is a need for boost (hills or accelleration). EGT's are rarely more than 900deg F and usually closer to 800deg under light load running flat. I am not looking for more power, but rather am trying to achieve better fuel Milleage. I think that this is not unrealistic thinking. I never get more than 17mpg on the highway and 14~ around town. Can I adjust the injection pump to gain slightly higher ETG's and more efficiency w/o violating the opacity test (colorado state emissions tests)? I believe it may be a slight timing adjustment that needs to be done. I am not interested in "cheating" the emissions tests, but think my goal of 18-21mpg is reallistic. Also, stock boosting should be closer to 18psi, so something is not right. The previous owner said the truck got 18psi for it's whole life until just before he sold it to me (180k, it has 195K now). He doesn't know what went wrong, it blew lots of white smoke. He took it to the dealer, they fixed that smoking problem but the boost never got back to where it was before. I have installed a new injection pump, I believe it is the stock type by Bosch, a VM series or something.
Somehow I need to turn up the fuel at the correct time to produce slightly hotter exhuast. How can I do this? I am mechanically inclined, but new to diesel motors.
I have checked for boost leaks, all plumbing looks good. It has a new oem lift pump as well, and a new paper air filter.

stackx2

well you can bump your timing up an 1/8 of an inch that will give you better fuel milege and it will lower your egts you dont want to have high egts. my truck gets about 21 mpg in town and on the highway doing75 i am only running 650 degrees on my pyro

MountainBen

OK, thanks, I know there is something in the "sticky" on how to do the 1/8" bump/rotation. I'll try that first. I've read threads that talk about fuel screw, smaoke screw and fuel pin adjustments and alterations, but I like to try one thing at a time. Hopefully the timing bump is the best first thing to do . . .