Another Mileage Thread to chew on

[DieselFiend]

I've been keeping track of my fuel mileage for about a month and I'm starting to think edge has incorporated an overhead mileage fooler along with their boost fooler. Before I installed the box my overhead was pretty accurate when compared to hand calculation. I just got back from a 600 mile weekend round trip and my overhead was showing 20 MPG (yes, I reset it at every fill up). When I hand calculated my mileage, I come out with 16. 75 MPG. Whats up with that??? This is driving at about 70 and under with the J/A set on 3/3. This is a two part story. Here's part 2. Occasionally I tow a couple snowmobiles. Trailer with the sleds probably weighs 2K. My milage only dropped to 15MPG. Is there something wrong here? I'm comparing this 3rd gen to my 2nd gen 02 that got 20 hand calculated. Could this be the result of winter blend fuel? I'm in southern Idaho and didn't think they switched over because of the mild temps here. I've also been running diesel injector cleaner in every tank. Hopefully someone here will give me some better insight. Otherwise I'm pulling the Edge J/A, buying some guages and a pyro and calling it good.

 

[Spooled-up]

I have the same situation as you with my Edge Attitude. The overhead shows 20 MPG but I'm averaging 18 or so hand calculated over the course of a tankful. I wouldn't be so quick to get rid of the Edge because of the error it causes in your overhead mileage. Try running it on level 0 for a while and see how you miss the power. I can't stand it!



I have been getting consistently better mileage (by 1-2 MPG) with the Edge installed. I don't baby my truck, but I don't do burnouts either. I have been running mine on level 3 (Drive) for the past few tanks, and have gotten the best mileage so far. Better than on level 2 (Mileage). The lower the level I use, the closer the overhead is to my actual mileage. When the truck was stock, I was getting about 1MPG higher than the overhead indicated.

 

[SKnopp]

The overhead display does not know about the added fuel the box is giving. It will read higher than you are actually getting beacause the box is lying to the ECM about the timing and what it is giving to the engine.

 

[betterthanstock]

The overhead MPG display gets its signals from the ECM.

The ECM adds up all the little electrical pulses that open the injectors, and keeps a record of the rail pressure (from the rail sensor) because at higher pressure more fuel will flow in the same "open" time. Then it sums up the total fuel used from the last time you pressed RESET.



It does NOT measure the fuel flowing thru the pump, as most of the fuel returns to the tank and is just used to cool and lubricate the pump and internally open the injectors (like a hydraulic servo).



EDGE fools the rail pressure reading, to force a higher rail pressure, and thus more fuel thru the same injector hole in the same time.

Honed injectors will flow more at the stock pressure and duration.

The VA3. 2 duration box keeps the injector open for longer, so it also flows more than the ECM is aware of.

Hence the overly optimistic MPG numbers.



In fact, the Cummins computer keeps a record of all the fuel that your engine has burned since new. This way they can tell if something is fishy, like very high mileage would indicate you are running a box or honed injectors.

It also keeps a permanent record of how hard your engine has worked, idled, etc.

 

[DieselFiend]

I thought the edge J/A for the 05's was timing and duration? Not pressure. Enlighten me...

 

[RankRam]

I thought the edge J/A for the 05's was timing and duration? Not pressure. Enlighten me...

You are correct, the 600/610 trucks are timing and duration, no pressure.

 

[BHolm]

The "600" trucks generally will not ever reach the milage level you had on the old truck. The 305/555 engines from '03 and early '04 are the milage champs IMO. Those trucks are capable of low 20's all day long. I even cruised at 80-85 mph an knocked down 18-19 in my '03 QC. The average, once broken in, on my '05 was 17-18. My '06 with an identical powertrain is up to about 15-16 with about 12k miles on it. Don't count on ever getting 20 again

 

[betterthanstock]

I thought the edge J/A for the 05's was timing and duration? Not pressure. Enlighten me...

Timing will not affect the accuracy of the overhead, duration will.

 

[Spooled-up]

Makes you wonder with all the emissions they are adding to new vehicles that decrease mileage, the exhaust is cleaner, but there's more of it!

 

[GWBourne]

i normaly get a hand calc 21. 2 MPG on the highway. cruise control is GREAT. just got back from new mexico, 13 hour drive with an averaged out MPG of 22. 1 doing 68 to 72 the entire way. never over 15lbs of boost, even through the hills.

 

[DieselFiend]

GW, more of a reality with a 2WD. You're much closer to the ground than me. Makes for a much more aerodynamic environment.

 

[Trophy1]

edge box

I have read here that the edge box will not increase fuel rail pressure for the 600's. What about the 03 HO's? Is it still duration and timing? I really don't want to mess up too much here as I have an 03 HO.