ORM fall off?

ccattie · **Posted:** Mon Jul 30, 2007 8:20 am

When I first did the ORM I went from like 420 a tank to 490/500. Now I am back to 430 or so. Do I have to run normal for a little and then switch it back to get the gains again? The power is still there, but the mileage isn't. Anybody else seeing it?
-c

dgeist · **Posted:** Mon Jul 30, 2007 9:21 am

ccattie wrote:

When I first did the ORM I went from like 420 a tank to 490/500. Now I am back to 430 or so. Do I have to run normal for a little and then switch it back to get the gains again? The power is still there, but the mileage isn't. Anybody else seeing it?
-c

Are your numbers based on the EVIC or hand-calculation? Some have suggested that the EVIC/ECU are slightly inaccurate for the short term immediately following the application of the ORM.

Dan

DarbyWalters · **Posted:** Mon Jul 30, 2007 9:40 am

I also think that some are aiming for unrealistic numbers based on others "single tank" mpg figures. The new EPA ratings are 19/23 and I am right in there for the city and a bit higher highway. Also the odometer is off about 4% on stock tires so you should adjust 100 miles to 104 miles for example. My 235/75/16s are 6% off!

fatweasel · **Posted:** Mon Jul 30, 2007 10:54 am

If you think about it the mileage should be lower with the ORM. the reason is that you are filling the combustion cyclinder completely with fuel/air rather than fuel/air/exhaust mixture.

It makes sense that the power would increase - more fuel/air = more power.

nursecosmo · **Posted:** Mon Jul 30, 2007 10:59 am

fatweasel wrote:

If you think about it the mileage should be lower with the ORM. the reason is that you are filling the combustion cyclinder completely with fuel/air rather than fuel/air/exhaust mixture.

It makes sense that the power would increase - more fuel/air = more power.

The response to this one should be interesting.

BiodieselJeep.com · **Posted:** Mon Jul 30, 2007 11:42 am

ccattie wrote:

When I first did the ORM I went from like 420 a tank to 490/500. Now I am back to 430 or so. Do I have to run normal for a little and then switch it back to get the gains again? The power is still there, but the mileage isn't. Anybody else seeing it?
-c

I kinda noticed that...but..with so much fiddling, I can't nail it down to some sort of ORM taper-off. Everytime you unhook the battery, the thing starts to "learn" all over again. I fiddle a lot!

Cowcatcher · **Posted:** Mon Jul 30, 2007 12:21 pm

Mine tapered off with real tires and a roof rack.

bugnout · **Posted:** Mon Jul 30, 2007 12:44 pm

Did you fill up from the same place?

Diesel quality can vary considerably. I have found that where I fillup affects my mileage much more than anything else. The cetan can vary from 40 to 50 and all points in between. My avg MPG varies from 21 to 26 depending on the quality of fuel. Even at the same station, One tank can be great and the next lousy.

ccattie · **Posted:** Mon Jul 30, 2007 2:32 pm

I wasn't really using the EVIC at all, I was speaking just from a miles traveled between fillups. I always get gas at the same truck stop by work every week. Earlier I was going ~490 miles when I was filling up with ~19 gallons. Now the odo reads something along the lines of ~420 and still taking ~19 gallons. If anything, since the ORM the EVIC seems more accurate/realistic. I just don't know if I need to pop the cable back on every other day or something to keep the mpg's up.
-c

KenJennings · **Posted:** Mon Jul 30, 2007 3:33 pm

nursecosmo wrote:

fatweasel wrote:

If you think about it the mileage should be lower with the ORM. the reason is that you are filling the combustion cyclinder completely with fuel/air rather than fuel/air/exhaust mixture.

It makes sense that the power would increase - more fuel/air = more power.

The response to this one should be interesting.

Ahhhh, yeah... The cylinder has the same volume regardless of what's being pumped into it.

Here's an oversimplification:

Let's say with the EGR running the cylinder is being filled with one part fuel, one part clean air, and one part recycled exhaust/sewage.

But, when the ORM suppresses the EGR the cylinder is being filled with one part fuel, and two parts clean air, since the EGR is not displacing good air for engine flatulence.

So, which one burns better: fuel + clean air, OR fuel + Already burnt air ?

(Or, which gum would you rather chew: a dry clean stick straight from the paper wrapper, or ABC gum stuck to granny's dentures?)

techTim · **Posted:** Mon Jul 30, 2007 8:18 pm

just ran 450 miles interstate with a bit of town driving, B20 and ORM for around 7000 miles previous, my highway mileage has been the same ORM or stock,
Cowcatcher, with my Yak rack and Basketcase installed I still get 27-28 by EVIC.
still waiting for the monsoon season to begin till I go with the 245/70/16's,

I'm still going with the thought that this CRD gets better mileage than my normally aspirated volvo, and most subaru wagons this side of the turn of the century, while being a "real" SUV that will tow 6000 pounds all day long if needed, and still wheel like a low range T-case should.

I run the ORM for the longevity of the engine, not the MPG. :wink:

as for the abc gum metaphor, I like the other one, the one where you are ingesting your feces :twisted:

Saber · **Joined:** Fri Jul 07, 2006 10:48 pm **Posts:** 160

have you cleaned your MAP sensor lately? MY MPG were slowly dropping then I cleaned the MAP, and they shoot right back up to were they had been.

Joe Romas · **Posted:** Tue Jul 31, 2007 11:31 am

Three weeks ago I drove my 19-22 mpg crd 360 miles each way to buy a travel trailer. I got 23 mpg going over. Coming back with 2500 a pound trailer and in a hurry to get back (ran the snot out of it :roll:

) I got 17 mpg. Not bad. BUT I filled up yesterday and with all in town and short trips I got 25.6 MPG

I have never gotten over 23 period in the 9000 miles on it. I cn only think that the trip back pulling my new camper loosened it up a little :lol:

There are two plugs under the hood that keep falling off and I had also just changed to synthetic fluid in both differentials and topped up the transfer case.

retmil46 · **Posted:** Tue Jul 31, 2007 11:54 am

Know it's been brought up before, but that's the standard advice for Cummins/Duramax/Powerstroke owners - to get the engine broken in to where it starts getting optimum fuel mileage, load it down and/or hook up a heavy trailer behind it, then go out and run the snot out of it for a couple thousand miles.

Noticed the same advice over on the MB forums - if you start seeing mileage and performance dropping off for no good reason, take it out and hammer it to blow all the crud out.

I guess with all diesels, every once in a while you have to show it a little "tough love" to keep them running happily.

dgeist · **Posted:** Tue Jul 31, 2007 1:26 pm

Joe Romas wrote:

Three weeks ago I drove my 19-22 mpg crd 360 miles each way to buy a travel trailer. I got 23 mpg going over. Coming back with 2500 a pound trailer and in a hurry to get back (ran the snot out of it :roll:

) I got 17 mpg. Not bad. BUT I filled up yesterday and with all in town and short trips I got 25.6 MPG

I had been getting about 24 MPG with mostly sort-trip highway driving. I went about 2 hours with a CANOE o the roof and nearly hit 28

I'll bet the canoe's shape ofset the turbulence normally created by the racks. Anyone want to make a canoe-shaped MPG mod?

ORM fall off?

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