Need help Cat c15

Hopefully a admin will move this to the right location for you.....

You need to research the "eighteen wheelers" forum a little father down. There you will find TONS of info on things you can do to get that ACERT to run better.
Here's the link
http://www.thetruckersreport.com/truckingindustryforum/trucks-eighteen-wheelers/

SOunds to me like he needs to get the ECM tuned and yes, the ACERT runs better at higher RPM, but 2mpg is a bit crazy! Maybe he has a boost leak somewhere?

 

Are you sure it is a twin turbo BXS Acert, or could it be a single turbo MBN? Big difference in engines and fuel mileage. Try to find Mr Haney on here. He is the resident Cat fixer.

 

We will need additional information to better understand the situation too. What is the sleeper height? What kind of trailer does he pull? What shipping lanes does he run? How heavy does he load? What transmission? What gear ratio? What size are the tires? How are you measuring the mileage? Is it odometer/hub miles since last fillup divided by gallons to fill tanks?

Regardless of this info that mileage, if accurate, it is too low in my opinion. What were the numbers from the dyno run? Temps? Blowby? HP? Oil pressure? Boost?

 

The dealer flashing the ecm put a bunch of low emissions garbage in the programming. Not surprising the fuel mileage didnt change. I saw the same thing happen when I had a dealer turn down the factory 525hp to 475hp. anyways we need more info, most important info would be your engine serial#. I like many others on here have turned to Mr Haney in the garage section for his services, advice on improving our cats with good results.

 

First off let me say a ecm tune is not going to magically fix this, obviously there is other issues.

When did the horrible fuel mileage start after the overhead or after the dyno?

Shocks me that they only have it set for 1650 trq at 490 hp.

What rear end ratio does the truck have?

If it has 3.36 or numerically lower cat recommends at least 1850 trq. With the 1850 program cat recommends a cruise rpm in the 1300 range. If it has 3.55 and 1650 they say to cruise in the 1400 range. All thou we have 3.55 with 1650 and we run 1350 often with usually increase in fuel.

What tranny does it have?

If it has a 13 or 18 i would shift at 1300 give or take depending on terrain. You have to caress the fuel pedal also.

Does the truck have a catalytic converter?

If so it could be clogged rendering the high flow mufflers useless. I removed our catalytic converter and plumbed in a piece of pipe.

Check boost couplers for leaks. I have found 3 with with visual leaks in the past year and a half. Especially on the turbo side of the engine the heat literally bakes the inside of them. Check all your boost clamps.

We had the same 4 mpg when we first got our 05 387 with acert. After a lot of money and trial and error we have been able so far this year to average better than 6 mpg on our ifta. And we haven't been to see Haney for a ecm tune yet.

We saw a substantial fuel mileage increase after overhead and later on we had the truck on the dyno and found the air compressor was throwing lots of harmonics and blow by into the crankcase. Since the compressor replacement we have been staying in the 6 pretty easily.

How much does he idle?

If we idle we can tell real fast. I think this thing drinks gallon and a half per hour.

 

Having the overhead adjustment done every 100k miles is routine maintinence. Making sure the alignment on all axles is in spec. Tossing out, replacing the air filter every 50K miles. Changing, cleaning fuel filters. Checking for boost leaks. All of this is routine maintinence. I would assume if this guy has been driving this truck for 2 years he would have been doing these things. Other than that it's just a matter of driving, idling habits. Once all that stuff is out of the way the best thing that can be done is an ecm tune. The stuff above will net you a couple maybe 3 tenths. A tune can pick up 5 tenths or more on an accert. I know all of us guys with tuned ecms sound like a bunch of cheerleaders but it's hard not to be happy with solid results that were easy to get, paid for themselves in 4 weeks time in my case, and only took about an hour to fix with a laptop. And if you are getting 6mpg avg with a 387 that's decent but you could do a heck of a lot better in that truck, you should be bumping 7, if you'd get your ecm tuned.

 

To the OP any numbers from the dyno would be very helpful.

I agree all these things should be done/checked has routine maintenance but I know many guys who have been driving and owned rigs for years who don't. I was just pointing out basics to rule out anything obvious.

Unless this guys drives like a tard and idles constantly I don't believe that's what's giving him 2mpg.

I'm not knocking a ECM tune. I do agree a ECM tune is a great thing but 5 tenths is going to net him him a whopping 2.5mpg. That's not gonna cut it. There is something else going wrong that needs to be addressed.

 

2mpg is Aussie road train territory.. i find it pretty hard to believe that it could be burning that much fuel.

sounds like somone may have either been loosing fuel, or selling it