What is going on with my MPG

plarkin

Active member
2012 Low Roof with SportsMobile (Fresno is now Field Van) Pop-top with 3.0L V6

Completed trip to and from Tucson (Oro Valley actually) after replacing the DPF bracket that attached to the transmission case. Also secured the scorched cable that goes to the DEF doser valve away from the exhaust - looking a a replacement for that wire. It has been a while since I have checked my mpg and was shocked to see it was 13.4 for my camper and we don't even have it loaded up, normally when loaded we get about18 mpg. So, I went back through my diesel receipts since June, and this is what I found for mpg.

Gals Miles MPG Comments
10.8 197 18.3 San Diego to Yuma
11.8 210 17.8 Yuma to Tempe
19.0 279 14.7 Around the Phoenix Valley
4.6 80 17.3 Still around the valley, top-up before heading to Santa Barbara
11.6 179 15.4 Ehrenberg AZ
20.2 352 17.4 Santa Barbara
16.4 271 16.6 La Jolla
7.0 79 11.3 La Jolla
15.2 265 17.4 Ventura
15.7 260 16.5 La Jolla
13.4 148 11.1 La Jolla
30.4 414 13.6 Del Mar - includes 10 $$ gals off I5 to get be to Del Mar
8.8 120 13.6 Del Mar
12.0 208 17.3 Yuma
19.1 324 17.0 Cordes Lake AZ
10.4 211 20.3 Tempe - trip up to Sedona
16.2 330 20.3 Tempe - includes trip to Cottonwood AZ
11.7 161 13.8 Tempe - trip to Oro Valley

The last entry was the first time I happened to check MPG which made be go back to June to see what was going on - varies greatly, need to understand why.

Almost 5,000 miles ago (now at 115,500) I replaced the wiring harness, heat exchanger, had injectors clean and tested (1 failed and was replaced & coded), glow plugs, serpentine and fan belts, idler pulleys, belt tensioner, alternator, water pump, radiator, oil filter, fuel filter, engine mounts and did an oil change.

I checked the engine air filter, so will replace that tomorrow. Went for a 30-mile drive and checked the brakes temperatures. all about 100+ degrees, so no sticking that I can tell. Will jack up tomorrow and inspect close up.

My DPF regens have not been happening till I get to 138% load and them it only regens down to above 30%. Attempted a driving force regen with Xentry, but it would not start because I could not get the pre DPF exhaust temp to 400 degrees, but after that I see that it reset the DPF level lower and I caught it at 6%. Be interesting to see at what % it starts the regen now.

We are setting off for South Carolina a week Monday so trying to get to the bottom of this. Will now start checking MPG with every fill-up to keep a close eye on it, starting with a short trip on Tuesday after air filter is replaced.

I have not had the AEM done yet, planning that for the new year.
Lance
 

Nic7320

2012 Solera 24S
My AEM solved my intermittent CEL issues after they put in a new exhaust system (Selective Catalytic Reduction filter, new Nox sensors, and a new ECU) , and later they replaced three parts on the DEF system, all under warranty. The DPF wasn't replaced, so they said. So before you spend a lot if time chasing your tail, get the AEM done and see how things improve.

But what impact the AEM has on my MPG is yet to be determined. I have to compare similar trips with similar loads to compare apples with apples.
 
Last edited:

lindenengineering

Well-known member
2012 Low Roof with SportsMobile (Fresno is now Field Van) Pop-top with 3.0L V6

Completed trip to and from Tucson (Oro Valley actually) after replacing the DPF bracket that attached to the transmission case. Also secured the scorched cable that goes to the DEF doser valve away from the exhaust - looking a a replacement for that wire. It has been a while since I have checked my mpg and was shocked to see it was 13.4 for my camper and we don't even have it loaded up, normally when loaded we get about18 mpg. So, I went back through my diesel receipts since June, and this is what I found for mpg.

Gals Miles MPG Comments
10.8 197 18.3 San Diego to Yuma
11.8 210 17.8 Yuma to Tempe
19.0 279 14.7 Around the Phoenix Valley
4.6 80 17.3 Still around the valley, top-up before heading to Santa Barbara
11.6 179 15.4 Ehrenberg AZ
20.2 352 17.4 Santa Barbara
16.4 271 16.6 La Jolla
7.0 79 11.3 La Jolla
15.2 265 17.4 Ventura
15.7 260 16.5 La Jolla
13.4 148 11.1 La Jolla
30.4 414 13.6 Del Mar - includes 10 $$ gals off I5 to get be to Del Mar
8.8 120 13.6 Del Mar
12.0 208 17.3 Yuma
19.1 324 17.0 Cordes Lake AZ
10.4 211 20.3 Tempe - trip up to Sedona
16.2 330 20.3 Tempe - includes trip to Cottonwood AZ
11.7 161 13.8 Tempe - trip to Oro Valley

The last entry was the first time I happened to check MPG which made be go back to June to see what was going on - varies greatly, need to understand why.

Almost 5,000 miles ago (now at 115,500) I replaced the wiring harness, heat exchanger, had injectors clean and tested (1 failed and was replaced & coded), glow plugs, serpentine and fan belts, idler pulleys, belt tensioner, alternator, water pump, radiator, oil filter, fuel filter, engine mounts and did an oil change.

I checked the engine air filter, so will replace that tomorrow. Went for a 30-mile drive and checked the brakes temperatures. all about 100+ degrees, so no sticking that I can tell. Will jack up tomorrow and inspect close up.

My DPF regens have not been happening till I get to 138% load and them it only regens down to above 30%. Attempted a driving force regen with Xentry, but it would not start because I could not get the pre DPF exhaust temp to 400 degrees, but after that I see that it reset the DPF level lower and I caught it at 6%. Be interesting to see at what % it starts the regen now.

We are setting off for South Carolina a week Monday so trying to get to the bottom of this. Will now start checking MPG with every fill-up to keep a close eye on it, starting with a short trip on Tuesday after air filter is replaced.

I have not had the AEM done yet, planning that for the new year.
Lance
Without getting too detailed.
, Do you have a fuel leak going undetected, and is the transmission going into lock up condition, or are you in permanent converter phase robbing you of fuel economy.
Dennis
 

Rob S

2008 Navion J on 2007 V6
Short trip stop and go in town vs longer trip steady speed driving makes a big difference.

Speed, load, and headwind vs tailwind makes a big difference.

So can slight differences in exactly how full the tank is each time you do a top-up. This is indicated by a higher than average mileage result immediately following a low mileage result.

I have even once found that a certain fuel station gave me consistently lower results, which can only mean they dispensed less fuel than it says on the pump.

Unless all your driving is under very similar conditions, you will often get significant differences from one tank to the next.

To get a good idea what is going on, if anything, is to calculate your average over several tanks, and then try to explain the deviation from average by the conditions encountered whenever it is significant.
 

plarkin

Active member
Without getting too detailed.
, Do you have a fuel leak going undetected, and is the transmission going into lock up condition, or are you in permanent converter phase robbing you of fuel economy.
Dennis
Thanks for the tips Dennis. Have spent a lot of time under the van and have not seem any leaking, but them I did not see the crack in the DPF bracket when I initially looked. Will follow the fuel lines from tank to the fuel filter then HP Fuel pump to verify and then check the low pressure fuel pump pressure.

How does one check for a permanent converter phase robber?

-Lance
 

lindenengineering

Well-known member
Watch the rev counter drop about 500 r/m in any gear except 1st but better still with a scanner observe the operation of the transmission & lockup clutch in live data.
That's how we do it .
Dennis
 

Kajtek1

2015 3500 X long limo RV
Most of those fuelings are on short trips, so subject to underfills due to air bubble on uneven pump pads.
Observe other factors as well. I've been recording each fill up my whole life and when above records look like having strange jumps on the paper, you should add wind, load, speed to them to make them comparable.
For example, my Bluetec sedan can make
60 mpg @ 60 mph
43 mpg when driven >80 mph
30 mpg when driven in Las Vegas, what is over 50% freeways, but with heavy traffic requiring constant gas pedal fanning.
 

plarkin

Active member
Rob S, thank you and I agree with your points, but some of the swings are too drastic. I have track the mpg in the past on every tank and never saw these variances.

One think I forgot to mention is that I see the engine load is 48% when stopped in gear, but putting it in neutral and reduces to 40% which still seems high.
Lance
 

Kajtek1

2015 3500 X long limo RV
I would worry about average from at least 3 fill ups. Again, single fill up, especially after shorter drive is subject to too many errors.
At idle the engine produce in the range of 20 HP, so 48% of that might be converter resistance.
 

plarkin

Active member
Watch the rev counter drop about 500 r/m in any gear except 1st but better still with a scanner observe the operation of the transmission & lockup clutch in live data.
That's how we do it .
Dennis
I believe the Xentry has that option so when my son comes over later today I will take him for a ride to monitor the computer while I drive.

Cheers, Lance
 

plarkin

Active member
My son did not make over today so will try with the wife reading the computer screen tomorrow, maybe have her capture it on her phone.
 

irvingj

2015 RT SS Agile (3.0L)
Ditto on the converter; mine will go from 35%, +/-, to 30 or less when shifting to neutral (if I'm remembering my numbers correctly) -- never over 40.
 

plarkin

Active member
Dennis - Is this the live data screen I should use for the test drive to check the transmission torque converter lock-up operation?

4606F92B-79AD-4EB2-9F17-6A045F8A3BC2.jpeg
 

Dima74

Independent & Self Reliant - From Chattanooga TN
2012 Low Roof with SportsMobile (Fresno is now Field Van) Pop-top with 3.0L V6

Completed trip to and from Tucson (Oro Valley actually) after replacing the DPF bracket that attached to the transmission case. Also secured the scorched cable that goes to the DEF doser valve away from the exhaust - looking a a replacement for that wire. It has been a while since I have checked my mpg and was shocked to see it was 13.4 for my camper and we don't even have it loaded up, normally when loaded we get about18 mpg. So, I went back through my diesel receipts since June, and this is what I found for mpg.

Gals Miles MPG Comments
10.8 197 18.3 San Diego to Yuma
11.8 210 17.8 Yuma to Tempe
19.0 279 14.7 Around the Phoenix Valley
4.6 80 17.3 Still around the valley, top-up before heading to Santa Barbara
11.6 179 15.4 Ehrenberg AZ
20.2 352 17.4 Santa Barbara
16.4 271 16.6 La Jolla
7.0 79 11.3 La Jolla
15.2 265 17.4 Ventura
15.7 260 16.5 La Jolla
13.4 148 11.1 La Jolla
30.4 414 13.6 Del Mar - includes 10 $$ gals off I5 to get be to Del Mar
8.8 120 13.6 Del Mar
12.0 208 17.3 Yuma
19.1 324 17.0 Cordes Lake AZ
10.4 211 20.3 Tempe - trip up to Sedona
16.2 330 20.3 Tempe - includes trip to Cottonwood AZ
11.7 161 13.8 Tempe - trip to Oro Valley

The last entry was the first time I happened to check MPG which made be go back to June to see what was going on - varies greatly, need to understand why.

Almost 5,000 miles ago (now at 115,500) I replaced the wiring harness, heat exchanger, had injectors clean and tested (1 failed and was replaced & coded), glow plugs, serpentine and fan belts, idler pulleys, belt tensioner, alternator, water pump, radiator, oil filter, fuel filter, engine mounts and did an oil change.

I checked the engine air filter, so will replace that tomorrow. Went for a 30-mile drive and checked the brakes temperatures. all about 100+ degrees, so no sticking that I can tell. Will jack up tomorrow and inspect close up.

My DPF regens have not been happening till I get to 138% load and them it only regens down to above 30%. Attempted a driving force regen with Xentry, but it would not start because I could not get the pre DPF exhaust temp to 400 degrees, but after that I see that it reset the DPF level lower and I caught it at 6%. Be interesting to see at what % it starts the regen now.

We are setting off for South Carolina a week Monday so trying to get to the bottom of this. Will now start checking MPG with every fill-up to keep a close eye on it, starting with a short trip on Tuesday after air filter is replaced.

I have not had the AEM done yet, planning that for the new year.
Lance
Pay attention to where you fill up and what type of fuel you use... For example, if I fill up my 2013 OM642 Sprinter at Pilot/Flying J or Loves, I average at 16-17 mpg on B5 diesel (label on the pump) @80 mph with no def/dpf/egr/ekas/tva... If I fill up at Speedway or Marathon/Murphy (Walmart here in the Southeast) with B20 (label on the pump) I average at 19-20 mpg @80 mph with A/C on in both cases and no DEF injection/Regenerations/Exhaust Gas re-circulation.
 

plarkin

Active member
Dima, I am usually very consistent when I refuel, even to the pump and orientation. The only exception is when when traveling long distance and not returning home in a day or two. But once I reach a destination I will pick a location to refuel with diesel and again pick a pump. In Bend Oregon there is a fuel station that sells fuel blends for custom engines and they have a diesel pump with no biodiesel even through Oregon mandates it. It cost a little more but when in that area that is where I always go. I am going to be more consistent in checking my mpg when I fill up and keeping notes on the what conditions may have resulted in the current mpg result. Today I topped up and from a few local trips and test drive to get transmission live data I am up to 16.4 mpg, same location that I got over 20 mpg and 2 consecutive weekend trips to Sedona and Cottonwood. Although I get better mileage in on trips with a lot of elevation change since I have to slow down to accommodate my wife's sensitive ears.
 

Kajtek1

2015 3500 X long limo RV
MB allows 5% of bio and I never heard about fuel-related problems in last 10 years when the mix become mandatory in USA.
The B20 sold in Michigan (?) creates some problem once the engine reaches 100,000 miles (per members report).
My Ford Powerstroke was approved for B20 just fine and I actually was calculating better mpg on this fuel. All within fill up/wind errors, so not really conclusive, but made me scratching my head.
MPG can play strange games. 2 days ago I used my GLE with OM651 engine to pick up some boxes 20 miles away.
Going there I drove freeway for almost 15 miles, so I averaged 19 mpg with flatbed trailer.
Going back, with 5'tall box and 2500 lb of cargo weigh, I choose street driving, where we have 6-lanes, 45 mph streets in Las Vegas.
So loaded rig averaged 22 mpg on street driving.
 

plarkin

Active member
Dennis - in the Xentry scan for Torque converter lockup clutch i have the following live data streams:

Target gear
Actual gear
Transmission oil temperature in selector level position R or D Degrees C
Selector level position [CAN, EWM]
Status of lock-up clutch {Open|Closed|Slipping]
Transmission output speed [1/min]
Speed difference of lockup clutch [1/min]
On/off ratio or torque converter lock-up [1/255]
Engine torque [Nm]

What should I be looking for in these data stream?

Can I see in Xentry what you are referring to: T/C 720 r/m?

Thanks,
Lance
 

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