Tuned a guys LB7; he now claims 6+mpg loss??

monster50iii

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Dec 5, 2014
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So I have tuned a few LB7's now, and all have gotten decent mpg (19-20 etc...). A guy came to me with an 02, that had an edge evolution installed on it. He flashed it back to "stock" with the edge, and then I read out his stock file and built off from it. It was a 02600605 OS. He claims he used to get 22-24mpg, and now he has seen as little as 14mpg. The read out stock file looked no different than the other stock files I had saved, but MAYBE the edge left something in?? Look my file over, and make sure I'm not blind, please!
 

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2004LB7

Active member
Dec 15, 2010
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Tell him to remove the pallet of concrete from the bed and stop racing it from light to light. 😁
 

monster50iii

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He claims it was hand calculated. He's a friend of my close buddy. He even told me this guy likes to tell stories. I'm not sure what to do for the guy, so i setup a new file with about 20% less pilot pulse, and I setup tunes 3, 4, and 5 with some experimental pilot timing. I've learned alot with pilot timing on my LMM after installing 60% LBZ tips. I dont just want to give up on the guy, but he's 100% certain his mpg is much lower after EFI. I know there's not but MAYBE 1mpg left in the tune...2 at most. I've already tried around 9deg main timing, and higher than stock fuel pressure and that did worse than the tune I just posted.
 

baggedLB7

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May 1, 2011
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Maybe he has some injectors going bad. Put the factory tune back in and have him check it again and verify.
 

kidturbo

Piston Tester
Jul 20, 2010
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Make sure Fuel Tank size didn't get changed, have saw that one throw it way off before.

I would reload the Canned tune he was running, then read it out with V2 and compare to stock and your own work.

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darkness

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Did you happen to change anything related to tire size? If he’s hand calcing and using the odometer and not actual miles that’ll throw things way off. Based on previous tunes not your tunes.
 
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monster50iii

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So he can't load in his old canned tune, he had edge reprogram his monitor so it is now just a cts insight now. That was the first thing I wanted him to do was flash back in the evolution programming to compare.

Going to double check his fuel tank size, and also if hes trying to correct tire size with the insight even though its already done in the tune. I think I remember him checking tire size on the edge, probably just his old habit from the past.
 

BlkMax

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Aug 31, 2008
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Did you happen to change anything related to tire size? If he’s hand calcing and using the odometer and not actual miles that’ll throw things way off. Based on previous tunes not your tunes.
I agree. I also have a hard time believing he was getting 22-24, I have NEVER gotten that kind of mileage with my LB7s. The best I have ever done with the way I drive is 19 with my triple truck on it's hottest tune driven responsibly, before the rods bent. :p
 

kidturbo

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Jul 20, 2010
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Yeah those are the two common mistakes I've made in the past that had me head scratching on mileage. And it could have been that edge had it reading high, and now you have it correct again.

Tough call, but your following the right path to figure it out.

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monster50iii

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Dec 5, 2014
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Fuel tank size was correct, the tire size deal I know he was trying to correct it with the edge. I'll make sure he doesn't mess with it. Besides that it kind of is what it is I guess. I doubt he's going to see anything magical with the pilot quantity/timing changes I made for him to test with, but who knows. Not sure if his truck has the dash readout, and he was basing much of his opinion on mpg by that, or if it was truly hand calculated.

He replaced a FPR not too long before I tuned it, part of me wondered if that could be part of it somehow (doubtful), but again he's very certain mpg dropped as soon as efi was programmed in. Has me wondering if the 6006 OS isn't jiving somehow. The crappy part is I must not have saved his stock tune like I thought. Just went digging for it and I cant find it.
 

RMJ_LB7

I have a screw loose
Feb 25, 2020
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Does the Edge change the fuel sending unit reading by chance? on my 06 cummins that I had I changed the sending unit reading to see what it would do and it made it seem like I was getting 23MPG pulling a trailer lol.
 

Chevy1925

don't know sh!t about IFS
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Oct 21, 2009
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you can try a placebo affect. take a stock tune, optimize timing and limiters so it feels like it has more power than stock, flash that optimized stock tune in and tell the guy its just a single tune but you need to run a test with this one before you build the dsp. see if mpg comes back or not.

otherwise i would be logging a bunch of things like injector balance and main injection rate, fuel pressure as you drive, what your timing is doing and looking for any oddities.

when my 02 was fairly stock on 37s and 3.73's i would get 20-21 from flagstaff down to phx (this was alot of down hill) and 16-17 on the way back up. both at 70mph, 1700rpm. that was on edge with attitude, PPE hot+2 and efi live. did that run alot as i was going to college in flagstaff and parents lived in phx.
 

darkness

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I definitely wouldn’t discount 22-23 mpg. When my ‘04 was newer and I had Edge with Attitude best highway mileage I saw was 23 mpg. I went from Las Vegas, Nv to Gallup New Mexico on a short bed tank of fuel.
 

2004LB7

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Dec 15, 2010
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I agree, 22/24 is possible. When I had my LB7 I took several trips between LA and Sacramento. 600 miles on 26 gallons.

Like the others said, test him on a stock or optimized stock tune and verify that the tire size is spot on. May want to check what he had for tire settings before too in case he had it wrong giving him higher (false) mpg
 

Mike L.

Got Sheep?
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I never got better than 20 on my LB7 running 85/90 on the hwy with a kill tune from RidgeRunner. (Tony )
 

DAVe3283

Heavy & Slow
Sep 3, 2009
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It is possible to get 22+ on a LB7. I'd get 19 in my CCSB if I kept the speed down on the highway, and my Suburban gets 22+ at 65 MPH.

Back when I had the Edge, the dash would display some really crazy high MPG, but it would hand calculate out about the same as what I got after switching to EFILive.

For what it's worth, I run 5-7° timing in the highway cruise range. Never saw much benefit going more than that.

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S Phinney

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The best I have ever gotten on a lb7 and that had 45 over Motorsports injectors was 21.4 hand calculated. It never got worse than mid 13’s towing more than 15k. That was once for that mileage. Usually it was 17-19.


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