Re-calibrating TCM

[deSanford]

Improved my fuel economy by having my TCM re-calibrated by Detroit Diesel Alision, Coburg Ore. by Ron. My TCM wouldn't go into 6th gear overdrive until I was going 67mph. I guess Navastar Monaco or Cummins didn't expect I would ever need 6th gear with my little ISB340 6.7L engine. They were right as this combo pulling a car just didn't have much "power". Speed limits towing in Calif. and some other highways limits vehicles with trailers etc to a max of 55mph. So my rig spent most of its time at 55 in 5th gear overdrive in econ mode with cruise control on. Well fuel mileage was just TERRIBLE. After a small "chip" and Ron's new calibration I now drive in 6th gear overdrive in econ mode with cruise set to 55. The RPM is between 1350-1400 and the trans and engine temps are GREAT (low). Now this is the TRUTH and NOT a how long was the fish you caught story. Mileage went from 6-7mpg to unbelievable, but TRUE to 15.2 as monitored on my new SCAN GAUGE D. The only trade off is when I hit the "Grape Vine" ( a real long up hill climb in Calif) did I end up going 22-25 mph in 3rd or sometimes 4th gear until I made it over the top. Mileage dropped down to 12.9 mpg when I finally reached home after 7.7 hours of driving. This included 2 hours on the 5-405 freeway bumper to bumper till we got home. Now I'm VERY HAPPY with my little full slide, one bedroom condo motorhome. deSanford

[Barlow46]

I want that Scan Gauge....what speeds were you running to get that 15.2 and were you using the scan gauge when you clocked the 6-7mpg also?

[ahicks]

Originally Posted by deSanford

Improved my fuel economy by having my TCM re-calibrated by Detroit Diesel Alision, Coburg Ore. by Ron. My TCM wouldn't go into 6th gear overdrive until I was going 67mph. I guess Navastar Monaco or Cummins didn't expect I would ever need 6th gear with my little ISB340 6.7L engine. They were right as this combo pulling a car just didn't have much "power". Speed limits towing in Calif. and some other highways limits vehicles with trailers etc to a max of 55mph. So my rig spent most of its time at 55 in 5th gear overdrive in econ mode with cruise control on. Well fuel mileage was just TERRIBLE. After a small "chip" and Ron's new calibration I now drive in 6th gear overdrive in econ mode with cruise set to 55. The RPM is between 1350-1400 and the trans and engine temps are GREAT (low). Now this is the TRUTH and NOT a how long was the fish you caught story. Mileage went from 6-7mpg to unbelievable, but TRUE to 15.2 as monitored on my new SCAN GAUGE D. The only trade off is when I hit the "Grape Vine" ( a real long up hill climb in Calif) did I end up going 22-25 mph in 3rd or sometimes 4th gear until I made it over the top. Mileage dropped down to 12.9 mpg when I finally reached home after 7.7 hours of driving. This included 2 hours on the 5-405 freeway bumper to bumper till we got home. Now I'm VERY HAPPY with my little full slide, one bedroom condo motorhome. deSanford

No doubt you can read the gauge, but maybe you could get back with us when you've confirmed that kind of mileage with actual consumption figures from a couple of trips?

[deSanford]

The speed I used was 55 to 57mph. With 90% at 55mph except when going through small towns and up the "Grape Vine". The Scan Gauge "D" is a powerful little unit that plugs into your 6-pin or 9-pin diagnostic connector. It has multiple trip computers, built-in and programmable digital gauges, and a performance monitor etc. I purchased mine at Camping World in Ore. for $152.00 NO sales tax. The new Navastar Monacos (short ones 37 or less feet) have aluminum side walls, except around drivers area. Going back to the gauge it will also show how much at the end of the day you have spent on diesel fuel and how many gallons to empty in your fuel tank. Have to mention it does show you how many gallons you have used. I believe it to be pretty accurate. It is also dead on what RPM you are running and your speed. What can I say......modern technology at an affordable price. I will list a few of the other items it monitors: distance, maximum coolant temperature, maximum speed, average speed, current tank of fuel, distance to empty, time to empty, and of course fuel to empty, manifold and boost pressure, oil pressure, fuel rate, battery voltage, engine load, throttle position, and intake temperature. Who could ask for more.........? deSanford PS buy one and get to know your vehicle. I will certainly keep everyone informed as I have another trip coming up. The journey is the destination to enjoy for me. I almost forgot the 6-7 mpg was before the Scan Gauge "D". We used the old inaccurate method of filling the tank and dividing the gallons into the miles traveled. I did my BEST to get good economy, but before the "chip" and reprogramed TCM my mileage was TERRIBLE.

[mel s]

Originally Posted by deSanford

Improved my fuel economy by having my TCM re-calibrated by Detroit Diesel Alision, Coburg Ore. by Ron. My TCM wouldn't go into 6th gear overdrive until I was going 67mph. I guess Navastar Monaco or Cummins didn't expect I would ever need 6th gear with my little ISB340 6.7L engine. They were right as this combo pulling a car just didn't have much "power". Speed limits towing in Calif. and some other highways limits vehicles with trailers etc to a max of 55mph. So my rig spent most of its time at 55 in 5th gear overdrive in econ mode with cruise control on. Well fuel mileage was just TERRIBLE. After a small "chip" and Ron's new calibration I now drive in 6th gear overdrive in econ mode with cruise set to 55. The RPM is between 1350-1400 and the trans and engine temps are GREAT (low). Now this is the TRUTH and NOT a how long was the fish you caught story. Mileage went from 6-7mpg to unbelievable, but TRUE to 15.2 as monitored on my new SCAN GAUGE D. The only trade off is when I hit the "Grape Vine" ( a real long up hill climb in Calif) did I end up going 22-25 mph in 3rd or sometimes 4th gear until I made it over the top. Mileage dropped down to 12.9 mpg when I finally reached home after 7.7 hours of driving. This included 2 hours on the 5-405 freeway bumper to bumper till we got home. Now I'm VERY HAPPY with my little full slide, one bedroom condo motorhome. deSanford

What coach do you have that gets 15.2 MPG?

I bet I can find 50 full size diesel powered coach owners that will NOT believe your claim of 15.2 MPG.... before you can find one that does!

If you have such a coach, tell us where you live, coach owners will flock to see it, (like people flocked to see the white buffalo calf).

The only ACCURATE way to calculate fuel mileage is to divide the number of gallons used by the miles driven.
IMO no gauge that shows an average of 15+ MPG is working correctly, (unless of course you only drive downhill with a tail wind). :-)

If any accessory could double the MPG of a vehicle with a diesel engine it would cost thousands of dollars, (and it would be worth it).

Mel
'96 Safari, 3126 Cat
getting an HONEST 8.5 MPG, (averaged over 100,000 miles)!

[JimM68]

I'm sorry desanford. I've always liked and respected you and your posts here...

But 15mpg off your rig is ridiculous. totally beyond belief. do a few runs using the odometer and actual miles, or maybe even using highway mile markers, as your "tuner" could be messing with the digital odometer....

Your rig, on a good day, mostly downhill with a tailwind, would be lucky to average 9 mpg for 100 miles, and certainly could not repeat that more than one other time in a thousand miles....
There are many here who get a little crazy with their mpg brags, and I've always just ignored them. You my friend, are held to a higher standard.

[deSanford]

I discovered a while back after I posted my GREAT MPG readings that my Scan Gauge "D" was not compatible with my MP-8. After I contacted the developer of the Scan Gauge "D" he explained to me how to recalibrate the gauge. So far I have filled the tank up 3 times and will continue to calculate the mileage using a yellow pencil. So far the best reading is 12.1 MPG. My DW and I will continue to use the old fashion way to figure the MPG, and after a few more trips average the results. The gauge fooled me..........deSanford

[walt2137]

Originally Posted by deSanford

I discovered a while back after I posted my GREAT MPG readings that my Scan Gauge "D" was not compatible with my MP-8. After I contacted the developer of the Scan Gauge "D" he explained to me how to recalibrate the gauge. So far I have filled the tank up 3 times and will continue to calculate the mileage using a yellow pencil. So far the best reading is 12.1 MPG. My DW and I will continue to use the old fashion way to figure the MPG, and after a few more trips average the results. The gauge fooled me..........deSanford

Yes DE we had the same issue with the VMSpc it had to be calibrated for mpg the OD and mph.

[bukzin]

Originally Posted by deSanford

I discovered a while back after I posted my GREAT MPG readings that my Scan Gauge "D" was not compatible with my MP-8. After I contacted the developer of the Scan Gauge "D" he explained to me how to recalibrate the gauge. So far I have filled the tank up 3 times and will continue to calculate the mileage using a yellow pencil. So far the best reading is 12.1 MPG. My DW and I will continue to use the old fashion way to figure the MPG, and after a few more trips average the results. The gauge fooled me..........deSanford

++++++++++++++++++++++++++++++++++++++++++++++

What does 'MP-8' stand for?

How much $$$ was the chip and re-calibration that you had done?

Thanks for sharing!

[H. Miller]

Originally Posted by bukzin

++++++++++++++++++++++++++++++++++++++++++++++

What does 'MP-8' stand for?

Google it..............

[deSanford]

I purchased the Scan Gauge "D" at Camping World in Ore. for $152.00 NO sales tax Bukzin. The recalibration for MPH is on going at this time. deSanford There is a lot of info on the web about "MP-8".

[JimM68]

Originally Posted by deSanford

I discovered a while back after I posted my GREAT MPG readings that my Scan Gauge "D" was not compatible with my MP-8. After I contacted the developer of the Scan Gauge "D" he explained to me how to recalibrate the gauge. So far I have filled the tank up 3 times and will continue to calculate the mileage using a yellow pencil. So far the best reading is 12.1 MPG. My DW and I will continue to use the old fashion way to figure the MPG, and after a few more trips average the results. The gauge fooled me..........deSanford

Thank you. 12 is way out there still, but only somewhat questionable.
I'm still thinking a 300 mile run, fillup to fill up, flat ground, on highway mile markers, might be in order...
If it turns out to be real, you'll have a lot of us looking at trading our ISC's for 6.7 ISB's...
your rig is a 33k GVWR, right?

For now, I'll standby my previous statements that Class A motorhome, gas or diesel, get 7 mpg, more or less, that is, 6 to 8.

[mel s]

Originally Posted by H. Miller

Google it..............

Thanks for the well thought out and finely presented informational answer!
(My second grader apparently knows as much abut the 'MP-8' as you do)!
Mel

[deSanford]

JimM68 if you do get a Cummins ISB340 6.7L make sure you install a MP-8 or you won't be happy with the lack of Torque. deSanford