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Author Topic: Fuel Mileage  (Read 1086 times)

Dave Atherton

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Re: Fuel Mileage
« Reply #15 on: October 10, 2017, 02:48:58 PM »
Fred, the ECM on Caterpillar engines reads out, fuel used engine idle hours, fuel used engine
running down the road gallons per hour, engine speed in rpm’s, engine fuel mpg. Note: the
engine reads only fuel used in engine not gen set or house heating. The information is pulled
from the ECM by using Caterpillar service tool called Cat ET and can be printed out. This has
preformed for many member by Dave at rally’s and many members have a copy of this. What
Dave posted earlier is information pulled from many motor homes. To answer your C-12 question,
the C-12 holds in most motorhomes 10 mpg. Again there are many areas fuel mileage can be
affected as stated by many. There are many add on information programs like the silver leaf
that also reads fuel mileage that may differ with Caterpillar OEM equipment but all information,
that is stored on Cat ECM is used for diagnostic information related to repairs and troubleshooting,
and only can be pulled from the ECM by Service tool called Cat ET of which Dave has.
Dave Atherton Retired Cat Mechanic
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Fred Cook

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Re: Fuel Mileage
« Reply #16 on: October 11, 2017, 01:48:47 AM »
Fred, the ECM on Caterpillar engines reads out, fuel used engine idle hours, fuel used engine
running down the road gallons per hour, engine speed in rpm’s, engine fuel mpg. Note: the
engine reads only fuel used in engine not gen set or house heating. The information is pulled
from the ECM by using Caterpillar service tool called Cat ET and can be printed out. This has
preformed for many member by Dave at rally’s and many members have a copy of this. What
Dave posted earlier is information pulled from many motor homes. To answer your C-12 question,
the C-12 holds in most motorhomes 10 mpg. Again there are many areas fuel mileage can be
affected as stated by many. There are many add on information programs like the silver leaf
that also reads fuel mileage that may differ with Caterpillar OEM equipment but all information,
that is stored on Cat ECM is used for diagnostic information related to repairs and troubleshooting,
and only can be pulled from the ECM by Service tool called Cat ET of which Dave has.
Dave Atherton Retired Cat Mechanic

Thanks for the info. I am getting ready to put fuel into my coach for the first time. Was wondering if I should use a fuel additive.... like opti-lube. Is an additive recommended?
Fred & Cindy
2002 Beaver Patriot Thunder 455
South Central Missouri

Dave Atherton

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Re: Fuel Mileage
« Reply #17 on: October 11, 2017, 03:36:12 AM »
Fred, Caterpillar does not recommend any fuel additive in all there engines such as injector
cleaners etc. They do approve Fuel anti-jell in diesel fuel tank in cold weather operations.
Dave Atherton Retired Cat Mechanic

Steve Huber Co-Admin

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Re: Fuel Mileage
« Reply #18 on: October 11, 2017, 05:11:54 AM »
Fred,
The C12 is not loaded down with heavy emissions controls and runs at a considerably lower RPM than some other CAT engines. Both contribute to the MPG. My C12 gave about 8.5 mpg, running at 65 MPH. (Wish I had another one in my current coach).
Steve
Steve
2015-          07 Contessa Bayshore C9,  400 hp
2013-2015: 00 Marquis Tourmaline, C12, 425 hp
2005-2013: 01 Contessa Naples, 3126B, 330 hp
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Bob Bulot

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Re: Fuel Mileage
« Reply #19 on: October 11, 2017, 07:16:09 PM »

[/quote]

Is this right.... C-12 gets 10 MPG?  Also will an additive make a difference?
[/quote

The consensus on this blog and others is that fuel additives are not recommended by most engine mfg, and generally do little or nothing to help modern diesel engines improve mileage or performance.
Bob & Carolyn Bulot
Palm Desert, California
06 Marquis Onyx
Cat C13
Ford C-Max Energi

Gerald Farris

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Re: Fuel Mileage
« Reply #20 on: October 12, 2017, 05:36:22 PM »
Fred,
There are many variables that influence fuel economy, and even though the C 12 is a very fuel efficient engine, I do not think that you should expect a consistent 10 MPG. From my experience, your coach normally runs in the 8 to 9 MPG range.

I have driven two different C 12 equipped coaches towing Jeep Grand Cherokees over the last 13 years, a 38,000 plus pound 2000 Marquis (8 to 8.5 MPG) and a 50,000 plus pound 2002 Solitaire (7.5 to 8 MPG), and in about 180,000 miles, I have never seen a consistent MPG over 8.5 regardless of the speed. I have seen 10 MPG on trips with a consistent tail wind, especially if I was dropping in elevation, but I have seen 5 to 6 MPG with a head wind or when gaining in elevation.

Gerald       
« Last Edit: October 12, 2017, 10:31:02 PM by Gerald Farris »
2002 Solitaire (2017 -  )
2000 Marquis, C12 (2004 - 2017)
1993 Patriot  (2000-2004)

Bill Lampkin

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Re: Fuel Mileage
« Reply #21 on: October 12, 2017, 10:18:32 PM »
My Aladdin monitor shows 5.5 mpg from 'born on' date (0 miles) to now. We bought our Patriot Thunder with 35000 miles on the odometer; we've put on about 10,000 mi over the last 3 summers, and the 5.5 mpg that the Aladdin reports seems to be pretty accurate, much to my dismay. 10 mpg on a C-12? Tell me it ain't so.....
2005 Patriot Thunder
525 hp C13

Dave Atherton

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Re: Fuel Mileage
« Reply #22 on: October 12, 2017, 10:28:11 PM »
Gentleman, fuel milage information off Caterpillar ECM, many good post and many areas that
are different. I guess being a trained with Caterpillar electronic engines and service tool to
Retrieve information off ECM called Cat ET is Caterpillar Service tool, to this date Cat ET is used
daily. All information is stored on History section starting since key started engine for the first
time. Myself cannot dispute with fuel milage pulled off ECM, with computer information using
Caterpillar service tool ET. In Next note: Cummins engines use what is call InSite service tool
to retrieve same information that Caterpillar ET does and many members have copy of information
That Dave has made for them doing Diagnostic readout for problems and active fault codes.
Dave Atherton Retired Cat Mechanic

Dennis Belfils

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Re: Fuel Mileage
« Reply #23 on: October 12, 2017, 11:19:29 PM »
Once again, lots of good info here. In following this fuel mileage thread, we have seen 3 different readouts on our rig & am not sure if different tire Mfg's have different dimensions or what may be the reason for our inconsistencies. Our Garmin GPS says 62mpg, speedometer says 59, Aladdin says 60-60.5. Can the ECM/speedometer be corrected to match the Garmin, as I believe it to be closest to actual?

Dave Atherton

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Re: Fuel Mileage
« Reply #24 on: October 13, 2017, 12:00:30 AM »
Dennis, I guess the last reporting Device is Caterpillar Service tool to readout all Caterpillar
ECM. One thing maybe several do not understand. The Caterpillar ECM is made strictly for
Caterpillar and the information on the ECM and other engine info. is bought from other companies
from Caterpillar and over the years certain values and information is held back from these
Aftermarket company's to maintain there edge on technical information for there own product
and service shops. There are several data connections to connect to ECM which mainly you
will find 6 pin J-1708 and 9 pin J-1939 to connect up your engine. Where problem comes into
play the software on aftermarket and Cat OEM not all the same along with fault codes. Again
service Cat ET is used in the electronic engine for many diagnostic problems and some areas
such a silverleaf and other brands Caterpillar will not give out much information but I do
know miles traveled, engine rpms, fuel used per Hour, miles per gallon can be bought up at
a caterpillar service shop as to what is on your Caterpillar ECM for a cost.
Dave Atherton Retired Cat Mechanic

Jerry Emert

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Re: Fuel Mileage
« Reply #25 on: October 13, 2017, 03:32:36 AM »
Just to add to the conversation.  My 03 PT with C-12, Aladdin displays MGP since born is 7.2.  12K+ miles this summer from FL-Alaska and now in Albuquerque is 6.9MPG.  I would sure love to see 10 MPG.  Better than the 5.0 I expected when I bought the coach 3.5 years ago.  until this summer I cruised at no more than 62.  I have increased to 68 this year just because the coach seems to have a sweet spot at 68-70 where everything just gets smooth and easy!

Edit:  I tow a 6500 LB PU truck everywhere!
« Last Edit: October 13, 2017, 04:47:25 AM by Jerry Emert »
Jerry, Chief USN Retired
2003 Patriot Thunder Lexington 40' 3 Slides
C-12 Ser#  2KS89983
4000MH

Dwight Wilson

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Re: Fuel Mileage
« Reply #26 on: October 13, 2017, 03:48:28 AM »
Hi Folks, I thought I would pitch in here. For the past 5 years we seem to average about 6.5 miles per gallon with our C13, pulling a 2011 Ford Edge, and we are almost always driving through mountains. We tend to drive the speed limit. I think the mileage is reasonable for the weight and aerodynamics (not).
Dwight Wilson
Calgary, Alberta
05 Patriot Thunder C13 Cat

Dennis Belfils

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Re: Fuel Mileage
« Reply #27 on: October 13, 2017, 01:24:28 PM »
Had another Senior Moment & miss-typed the readings in earlier question. Should be MPH not MPG. Am trying to get consistency between the 3 different readouts I am getting. I can only guess that MPH are based on rear end ratio, tire size, & engine RPM for the speedometer & Aladdin readouts. Not too worried about gas mileage with this rig.

Bill Sprague

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Re: Fuel Mileage
« Reply #28 on: October 13, 2017, 02:15:38 PM »
Cat once published a book called "Understanding Coach/RV Performance".  I no longer have a printed copy but I can email anyone a .pdf version.   I'm not comfortable posting my email address on any forum, but it is in the membership book.  Send me a note and I will return it with the .pdf attached.  You might also be able to send me a "private" email on this forum.

Bill

« Last Edit: October 13, 2017, 02:17:46 PM by Bill Sprague »
Bill Sprague
Past Region 1 VP
2015 PleasureWay Pursuit w/6.8 L Triton V10
PAST 12 year owner of '04 Monterey w/Cummins ISC 350
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Steve Huber Co-Admin

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Re: Fuel Mileage
« Reply #29 on: October 14, 2017, 04:15:24 PM »
The CAT document "Understanding Coach/RV Performance" covering the contributing factors to fuel mileage is published in the Technical Library under Beaver Owners Manuals and in Common Problem under Poor Fuel Mileage. Thanks to Bill Sprague for making it available.
Steve
Steve
2015-          07 Contessa Bayshore C9,  400 hp
2013-2015: 00 Marquis Tourmaline, C12, 425 hp
2005-2013: 01 Contessa Naples, 3126B, 330 hp