Sorry I kinda double posted this. Thanks for all the info on the valve adjustment sounds pretty straight forward. I am wondering if I also have another problem I decided to start a new thread to adress another Question I had. Something I also seem to noticed lately and I confirmed this tonight(just filled up after setting trip odometer last tank). I only get about >11MPG regular driving some city some highway no towingnot alot of idiling, could my valves needing adjusted cause this? I've also heard that the lift pump can go weak or out and the injection pump will struggle its way and the truck will run, but this will very soon tear up the injection pump? Everything seems to run smooth and ther is the same power that was always there no rough idleing. I do have the Tsp #10 plate with their boost elbow and I used their template when putting it in which puts it in the factory position , not slid forward like I have read other do. I did not adjust the star wheel. I get a small puff of dark smoke under normal acceleration. then again as the engine gets up to about 2400 RPM. but this is barley visiable because at that piont you are moving pretty good. My boost rises steady and tops out at about 28~29. My EGT rise and lower steady topping out at about 1,000 but by the time you shift they go back down to about 800, they hold about ~700 when going down the road. I rember when I first purchased the truck I swear it got better milage than this, although I dont rember the exact number. Am i just asking too muck from my MPG with these modest upgrades or is there something i need to investigate more. Thanks again in advance Wayne

 

I'm new at this as well but I think the lift pump pressure comment is directed more towards teh 24v guys and not the 12v like you have.

I know I turn anywhere from 17-20mpg with my rig depending on pulling a trailer or hotrodding vs normal everyday driving. I shift at or around 2k and go easy on the go pedal and the mileage rewards me. I do a good mix of highway/city driving pretty much equal to get the numbers above. If I'm out dumping tons of black smoke, repaving the streets with my tires and such I get the lower number same as pulling the TT.

Maybe try shifting a little sooner and go easy with the foot see what happens. Also don't forget the simple stuff either check your filters...

I dont' have enough experience yet with these Cummins to comment on the valve lash adjustment so I'll let the more experienced boys take that one on...

 

If your valve adjustment is way off it might affect it some. Your biggest culprits for low mpg's will be, winter blend fuels, cold temps will make thick oils and higher friction in the axles and trans, driving habbits and the speed you drive.Have you bumped up your timing yet? When I advanced my timing I got a solid 1.5 mpg improvement.

 

I have not messed with the timming , it is at the stock setting. I drive this truck super easy, so easy in fact that i dont normally go above 2000 RPM much. That being stated Today I got on it a little to get through a intersection and I lost all power above 2200 RPM. Like I said I go very easy on it. Maybe when I first put the plate on I drove it harder. Let me put it this way, today I further tested the problem and my truck in gear it will not go past 2300 RPM!!! I cannot force it to go past this even with the pedal all the way to the floor. I know for a fact that it did not used to do this. It is like there is a rev limiter only I now there is not one. Hopefully someone can help Thanks in advance Wayne

 

so did your mileage go down after you did a valve adjustment?

if so, I would re-set the valves being ultra careful to get them set right and take that variable out...

Forrest

 

I have not adjusted the valves, I have just noticed this within the last few days and there is alot of snow on the ground about 12"now and my truck will not physically fit into my garage