cm2250 -cm871

[JimT]

(09-29-2020 )BigfootDiesel Wrote:  im aware of there fuel pump issues and it has allready been replaced and it idles very smooth ,is there a way to tell when the pump is going out or just replace every so often kinda thing?

the power part im actually looking because id like to have a truck with some more grunt and be able to pull heavier loads easier , allways had truck in the mid 400, truck runs and has no issues.

For the Fuel Pump, there is no magic crystal ball to let you know before it fails. BUT it's a very simple job to unbolt and remove the head from the pump to inspect it every year or maybe 100,000 miles. Work it in with other period maintenance, like an overhead adjustment, battery cable cleaning, EGR tuneup (if functional), etc... Cummins says to replace the gasket (on the fuel pump head) if removed, but if it's still in good shape it should be fine to reuse at least once. Figure about 400,000 miles between preventative rebuilding of the pump head.

I personally rebuilt my fuel pump head in July of 2019. By the time I did my inframe in August of this year (2020) the rollers were already worn and the cam had noticeable damage. Ended up replacing the entire pump this time. I'm guessing I missed some small damage to the cam the first time I was in there and after a year it just got worse. The key point however is to inspect it periodically and you will catch any damage before it becomes catastrophic.


As far as increasing the HP on the 2250 it will depend on the internal parts. If memory serves me correctly there's 4 different cylinder liners with 2 different HP ratings. Also the Oil Cooler comes in 2 different versions, a steel one rated up to 500 HP and an aluminum one rated at or above 500 HP. That's basically the division of parts in the cm2250. They are built with either sub 500 HP or above 500 HP parts and the rest is programming. If the CPL doesn't support higher HP then don't push your luck. I got lucky, my 450HP ST cm2250 was built with all the higher HP parts.

I'm right there with Rawze and Waterloo. I keep her between 1550 and about 1800 when in the upper gears. With my 3.36 rears and a 13 speed I end up getting my best mpg running about 62 mph at 1550-1560 rpm in 12th with 5-10psi of boost. If I can't keep it above 1550-1600 with 21psi of boost (or less) then I downshift until I find a gear that can do it. If the grade is steep enough and I find myself getting down around 35-45mph then I might increase the boost a bit, but usually only for shorter climbs. My rule of thumb is, higher boost = higher rpms. Occassionally, I'll run up in 13th gear at 1500 rpms doing about 72 mph with a mid-roof sleeper and an empty flatbed, but only on relatively flat ground. One day I'll have the extra money to re-gear this truck and make 13th more usable, then I should be able to get even better fuel mileage without beating up the engine.