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730Industries · 02-13-2022, **(Subject: CM2250 Poor fuel mileage )**

I have the exact same issues with my boost minus the awful fuel mileage. My dash matches doing fuel consumption by hand. but my boost holds hard at 30 up to 1500ish rpms and then drops to 22 or so by the time i hit 1800 rpms.

i had RR put a base tune on it after i got rid of all the junk and i got about 5.3mpg pulling 34k cross country with some really awful headwinds at 70mph at 1590rpm. So it wasn't completely bad. But empty i am barely getting 7.3mpg at 65mph at 1450rpm.

curious if its a combination of winter weather and the speed i drive?

the boost problem is my biggest issue. It has done that the entire time i've owned the truck. before i got an inframe. After i got an inframe. before and after RR did his tune. It's like the truck doesn't like going over 1500rpms to produce any boost.

Rawze · 02-14-2022, **(Subject: CM2250 Poor fuel mileage )**

(02-13-2022 )730Industries Wrote: [align=left]I have the exact same issues with my boost minus the awful fuel mileage. My dash matches doing fuel consumption by hand. but my boost holds hard at 30 up to 1500ish rpms and then drops to 22 or so by the time i hit 1800 rpms....

according to your other thread here, you have a CM2350...
ref: http://rawze.com/forums/showthread.php?t...7#pid69687

just an FYI: max boost allowed for ...

CM870,CM871 = 38-39 PSI max with higher HP tunes(500+ hp), and 37~ish psi max for mid-tier power ranges (below 500 hp). 39 is the upper extreme limit.

CM2250's = 34-36 PSI max no matter what HP your trying to make. 36 is the upper extreme limit.

CM2350's = 33~ish PSI max for mid-tier power levels and 33-34 psi max for high hp. 34 is the absolute upper extreme limit on this engine.

X15's = 28-30~ish PSI max for mid-tier power levels and 30-32 psi max for high hp. 32 is the absolute upper extreme limit on this engine.

730Industries · 02-14-2022, **(Subject: CM2250 Poor fuel mileage )**

(02-14-2022 )Rawze Wrote:
(02-13-2022 )730Industries Wrote: [align=left]I have the exact same issues with my boost minus the awful fuel mileage. My dash matches doing fuel consumption by hand. but my boost holds hard at 30 up to 1500ish rpms and then drops to 22 or so by the time i hit 1800 rpms....

according to your other thread here, you have a CM2350...
ref: http://rawze.com/forums/showthread.php?t...7#pid69687

just an FYI: max boost allowed for ...

CM870,CM871 = 38-39 PSI max with higher HP tunes(500+ hp), and 37~ish psi max for mid-tier power ranges (below 500 hp). 39 is the upper extreme limit.

CM2250's = 34-36 PSI max no matter what HP your trying to make. 36 is the upper extreme limit.

CM2350's = 33~ish PSI max for mid-tier power levels and 33-34 psi max for high hp. 34 is the absolute upper extreme limit on this engine.

X15's = 28-30~ish PSI max for mid-tier power levels and 30-32 psi max for high hp. 32 is the absolute upper extreme limit on this engine.

Not sure where i said it was a 2350, but it is definitely a 2250. Should i ask RR to look and anything specific when i talk to him again? I'm obviously completely out of my league when it comes to tuning questions. I just have my observations for driving it for 2 weeks since all the changes.

Rawze · 02-14-2022, **(Subject: CM2250 Poor fuel mileage )**

(02-14-2022 )730Industries Wrote: ...
Not sure where i said it was a 2350, but it is definitely a 2250. Should i ask RR to look and anything specific when i talk to him again? I'm obviously completely out of my league when it comes to tuning questions. I just have my observations for driving it for 2 weeks since all the changes.

you are correct.. the PDF file shows a CL10138 file. That is a CM2250 file. - Must have missed that. thanks for the correction.

Anyways, I posted the numbers for each model as an FYI for those curious.

amermextrucker · 02-15-2022, **(Subject: CM2250 Poor fuel mileage )**

I've been seeing 34 psi a couple of times and 33 psi more than I like. It just started doing this. MPG are awful I'm barely getting 5.0 miles per gallon. Engine is a CM2350 as well.

I'm going to start at the IMAP sensor.

Rawze · 02-18-2022, **(Subject: CM2250 Poor fuel mileage )**

I was at Mr. hags yesterday. There was a truck there that got 5 mpg no matter what anyone did to it. - I looked it over pretty well (without cranking it up or doing any tests) .. and found that when I cracked open the davco drain valve, letting it pour into my hands.. the first few drops that came out were (red) coolant, followed by fuel.

Last i checked, these ISX engines do not run on steam.. so i told the guys at the shop to test it for leaking injector cups.

After the injectors were all pulled out and the coolant system was pressurized to 6 PSI.. 4 of 6 cylinders were seeping coolant.. one of which was a steady "drip, drip, drip".

That is the main contributor of why his fuel mileage was so bad, however...

This truck was also severely neglected. The air dryer and its filter were completely shot. There was so much water (from moisture)in the air tanks (several gallons of water) that it is a damn miracle that the brakes still operated. ALL of the shocks were completely shot, the truck had a set of brand new tires on it and they were already wearing lop-sided and damaged because not a single tire was mounted properly on its rims. The alignment groove on the tires was so far off at the rim that one side it would be 1/8" visible, and the other side, it was under the edge of the rim. None of the alignment dots for the valve stems were aligned.. it looked like some moron had installed the tires .

Almost 700k on the truck, Overhead cam had bot been touched since truck was new.. crank shaft damper had never been replaced,.. wheel bearings had never been re-torqued, wheel seals seeping, everything on that truck had been severely neglected. It was a complete joke!, and the truck owner kept saying to me.. "BUT THE SHOP I TAKE IT TO CHECKS IT OVER FOR ME" .. "BUT THE SHOP THIS" .. AND "BUT THE SHOP THAT".. AND "BUT THEY ARE GOOD PEOPLE" .. AND "BUT I HAVE A GOOD MECHANIC" ... AND ON AND ON THIS GUY KEPT REPEATING HIMSELF!!>...

I GOT MAD AT HIM AND ... "BUT YOU ARE THE PROBLEM BECAUSE YOU DO NOT TAKE RESPONSIBILITY FOR YOUR OWN EQUIPMENT AS A TRUCK OWNER AND YOU ARE THE ONE WHO IS TO BLAME BY NOW!!!>.. TRUCKING DOES NOT WORK LIKE THAT ... YOU ARE THE ONLY ONE WHO WILL MAKE THINGS RIGHT.. NOT SOME DAMN REPAIR SHOP!!!.." .. and of course, he got a bit mad at me because I guess people do not want to hear that owning a truck requires more than holding the damn steering wheel and taking it off to everywhere instead of keeping after things properly.

This is a very fine example of what is wrong with trucking these days... too many people think they can own this type of commercial equipment and just "hold the steering wheel".. and expect everyone else to do everything for them, and then wonder why their whole world falls apart around them.

amermextrucker · 02-19-2022, **(Subject: CM2250 Poor fuel mileage )**

(02-18-2022 )Rawze Wrote: I was at Mr. hags yesterday. There was a truck there that got 5 mpg no matter what anyone did to it. - I looked it over pretty well (without cranking it up or doing any tests) .. and found that when I cracked open the davco drain valve, letting it pour into my hands.. the first few drops that came out were (red) coolant, followed by fuel.

Last i checked, these ISX engines do not run on steam.. so i told the guys at the shop to test it for leaking injector cups.

After the injectors were all pulled out and the coolant system was pressurized to 6 PSI.. 4 of 6 cylinders were seeping coolant.. one of which was a steady "drip, drip, drip".

That is the main contributor of why his fuel mileage was so bad, however...
...

I don't have any of those issues. It's amazing how some people treat there equipment & then blame it when it fails.

Rawze is the IMAP where I should start ? Also would u suggest replacing back pressure sensor as well ?

FnG92 · 02-19-2022, **(Subject: CM2250 Poor fuel mileage )**

I think the same thing is wrong with my 2350. I'm so excited to see what fixes this!!!

Truckdriven · 02-28-2022, **(Subject: CM2250 Poor fuel mileage )**

(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?