CM2250 Poor fuel mileage

[Truckdriven]

(02-11-2022 )Rawze Wrote:  

(02-11-2022 )Truckdriven Wrote:  ...Total_fueling~ 264.16 m/g stroke
...

264 mg/stroke is roughly about 440-460~ish HP or so worth of fuel.

Since your program (that you sent me a while back for review) shows it is a 450HP/1750trq program, this is about right. This means that the ECM is at least doing what it is told and that it "thinks" it is making full power etc.

The turbo only being at 22% sounds a touch low, 32-33% would be more like what is typically needed for a W900 truck at that RPM/Power level ... but it being a W900, they are known for requiring lower positions than other trucks, simply because the larger 4" intake piping + CAC is very large, have almost no restrictions in them. Raising it a bit could be done.. but you also complain about massive fuel mileage losses too though. - This would not be caused by turbo programming alone. - This implies that there has to be an air(or exhaust) related issue somewhere with the truck/engine.

This means that if your getting the fuel.. and the boost is lower than expected, ... it sounds exactly like maybe an air (or exhaust) related issue to me so far. Perhaps a boost leak somewhere that only happens under load?, or perhaps maybe a clogged up air filter?, clogged up exhaust?... damaged turbo turbine blades?, something... - At least that is what you posted so far.. but it literally anyone's guess. Engine problems that are not obvious are impossible to troubleshoot via "texting" and "forums" alone.

I.E.> It is all just blind guessing.


In any event, the boost (turbo programming) should likely be corrected so that it makes more like 34-35 psi under full max loads, and not only 28-30 like you described above.

Maybe a trip to Mr. Hags with it? if no one can find it?.

I thought I would try to give an update on this situation, I had R R adjust the turbo settings and Max boost is still the same making me believe this is a mechanical problem more than programming, however cruising on the highway it is more responsive and easier to keep your speed without getting in the throttle as hard. I know you mentioned taking it to mr. Hag but also tell us truckers to take things into our own hands so I would like to do my due diligence before I do that also I never get into his area so that is not very easy. I did take intake and exhaust off and inspect turbo Wheels and saw no sign of damage or concern there. Is there anything else in the turbo I should be looking at?? Also I never gave an EGR tune up any thought since this engine is demandated but I'm thinking it's very possible the intake manifold could be very sooted up, is the intake manifold small enough on these engines to clog up with soot?? Could the head be clogged enough to cause restriction problems? I've seen in the automotive World they use Walnut blasting to clean soot out of valves would that be an option in this situation?