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zare6 · 01-31-2017, **(Subject: ISX 2350 485 )**

Hi anybody experiencing declining fuel economy with this engine? I have 200000 miles on it, boost goes to 38 psi runs great dynoed at 440 hp at the wheels, dpf filters are clean, started off at over 7 mpg now I'm down to 5.

jimeneztrans84 · 01-31-2017, **(Subject: ISX 2350 485 )**

First things first. Egr tune up.... you're right at the mile interval for overhead and egr tune up. Watch rawze's videos. Put a oil by pass filter set up on that engine asap.

Waterloo · 01-31-2017, **(Subject: ISX 2350 485 )**

More than likely your fuel, winter blend. Try and stay away from Pilot and Flying J, they put water in the fuel, bio or ethanol blend, kills your fuel mileage and in time your motor.

Mr Hagg · 01-31-2017, **(Subject: ISX 2350 485 )**

WOW 38 psi boost sounds high...

RPM1 · 01-31-2017, **(Subject: ISX 2350 485 )**

(01-31-2017 )Waterloo Wrote: More than likely your fuel, winter blend. Try and stay away from Pilot and Flying J, they put water in the fuel, bio or ethanol blend, kills your fuel mileage and in time your motor.

out of curiousity u know for a fact they put water in there fuel ? could u explain that one ?
i dont get down south much , but are there many places u can get straight diesel no bio ?

Billdozer2 · 01-31-2017, **(Subject: ISX 2350 485 )**

(01-31-2017 )RPM1 Wrote:
(01-31-2017 )Waterloo Wrote: More than likely your fuel, winter blend. Try and stay away from Pilot and Flying J, they put water in the fuel, bio or ethanol blend, kills your fuel mileage and in time your motor.

out of curiousity u know for a fact they put water in there fuel ? could u explain that one ?
i dont get down south much , but are there many places u can get straight diesel no bio ?

Their fuel has a high water content. I was a driver leader for a couple of months and during the winter, we constantly had issues of the Davco filter icing up. All of our trucks were fueling at Pilot's. When Pilot screwed over a bunch of companies with their fuel rebate fiasco, the company I worked for cancelled their fuel contract and we stopped getting fuel at Pilots and only got fuel from TA's. After that, the Davco's stopped icing up.

That's the only proof I have. I would have blamed it on a bad batch/delivery of fuel, but it went on for months.

RPM1 · 01-31-2017, **(Subject: ISX 2350 485 )**

(01-31-2017 )Billdozer2 Wrote:
(01-31-2017 )RPM1 Wrote:
(01-31-2017 )Waterloo Wrote: More than likely your fuel, winter blend. Try and stay away from Pilot and Flying J, they put water in the fuel, bio or ethanol blend, kills your fuel mileage and in time your motor.

out of curiousity u know for a fact they put water in there fuel ? could u explain that one ?
i dont get down south much , but are there many places u can get straight diesel no bio ?

Their fuel has a high water content. I was a driver leader for a couple of months and during the winter, we constantly had issues of the Davco filter icing up. All of our trucks were fueling at Pilot's. When Pilot screwed over a bunch of companies with their fuel rebate fiasco, the company I worked for cancelled their fuel contract and we stopped getting fuel at Pilots and only got fuel from TA's. After that, the Davco's stopped icing up.

That's the only proof I have. I would have blamed it on a bad batch/delivery of fuel, but it went on for months.

i was just curious , iv had bad fuel my self , i blamed in on the store shitty tanks or what not , i cant see any one sticking a water hose in there fuel tanks and some one not letting the cat out of the bag , around hear most come out of the same refinery no mater who's brand is on it

Waterloo · 02-01-2017, **(Subject: ISX 2350 485 )**

The water is in the bio diesel ethanol crap they blend with the straight diesel. No one is sticking a garden hose in the fuel tanks, but you do get water in all diesel fuel, straight or blended, condensation and what not from the tanks, etc. That is why a good fueling station will have water separators in the system or on the hoses.

If you want straight diesel, check the fuel pump stickers, by law they are supposed to label the pumps if they are using straight diesel, or that blended crap. TA for the most part sells straight diesel fuel, but I don't trust that they change out the water filters enough. I have gotten bad fuel at the one by my house. The fuel island is filthy, and that pretty much says all I need to know about their tank and fuel maintenance program. I have a few mom and pops that I use frequently. They have staff on hand that regularly changes out the water filters on the pumps and takes care of the equipment. Sounds funny, but I am interviewing the employees and or manager before I fuel.

Rawze · 02-01-2017, **(Subject: ISX 2350 485 )**

(01-31-2017 )zare6 Wrote: Hi anybody experiencing declining fuel economy with this engine? I have 200000 miles on it, boost goes to 38 psi runs great dynoed at 440 hp at the wheels, dpf filters are clean, started off at over 7 mpg now I'm down to 5.

A CM2350 has a higher compression ratio than older model engines. That engine can make 700+ HP with only 32-33 lbs of boost. It should be peaking about 32-lbs of boost or so max from factory.

I have test driven many that were factory stock, and it is not normal to have 38. - It is simply too high and it is over-boosting. This alone will make your fuel mileage and engine efficiency suffer/significantly lower. It will also set the engine up for more severe problems like detonation, liner issues, and a cracked head.

Perhaps someone put the wrong (or a bad) program in the ECM? -- OR perhaps you have some sensors reading incorrectly that is causing it.

Start with a thorough EGR tune-up, replace all the EGR sensors, etc. and find out why it is over-boosting.

Also check to ensure your Doser injector is not leaking.

Check that your decomp. tube is not partially clogged. -> http://rawze.com/forums/showthread.php?t...07#pid1807

Also, you should perform an injector leak test...