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Old 04-08-2007, 04:20 PM   #1 (permalink)
06DMAX00CAMSS
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How does the computer calculate fuel mileage?

I installed a PPE boost controller the other weekend and now my DIC is lower on the mpg. I haven't used a full tank yet with the controller to manually calculate the mileage. It usually reads 20-21 mpg which is really 15-15 mpg when hand calculated, now its reading 15-16 which is what it should read. I surely hope its not making my mileage worse and that its making my DIC accurate.
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Old 04-08-2007, 05:58 PM   #2 (permalink)
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The DIC is really just an estimate for fuel mileage based upon some mathematical formulas that the GM engineers came up with. It uses throttle position, speed, rpm, MAF value, etc.......and develops a fuel consumption value.

Any changes to the truck will mess up the mileage calculation (tires, programmers, gears, etc.)
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Old 04-08-2007, 07:07 PM   #3 (permalink)
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Did you reset the DIC average fuel mileage display? Took me about 12000 miles to realize that!
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Old 04-08-2007, 08:18 PM   #4 (permalink)
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Boost controller lies to the computer. Probably thows off the DIC. With manual boost guage and Edge Juice/Attitude combo, both were the same untill I added boost controler. Then J/A was off by over ten at WOT. Even at partail throttle, J/A was off.
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Old 04-08-2007, 10:07 PM   #5 (permalink)
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Of course I remember to reset the MPG, including the fuel used, trip, etc. I've got a Predator set on 120hp and it threw the DIC off by 5 mpg. So if my DIC displayed 20 mpg at the end of the tank, I really got like 15.

What's happening now with the boost controller is the mpg displayed on the DIC is actually even lower. I'm not sure how accurate it is now to hand calculating. We shall see whenever I use up this tank.

If indeed the calculation is based on MAF value, then it probably is the boost controller because it plugs into the MAF.
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Old 04-08-2007, 10:13 PM   #6 (permalink)
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I have the boost controller installed on my truck and the mpg on the DIC did not change. So not sure how yours is working.
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Old 04-08-2007, 10:22 PM   #7 (permalink)
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What programmer are you running though?
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Old 04-08-2007, 10:38 PM   #8 (permalink)
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Most everything will throw off the mpg's, it is just an estimate anyway, I always hand calculate to get the MPG's.
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Old 04-08-2007, 11:01 PM   #9 (permalink)
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the easyest way i found to do it is if u want to know your highway miles what i do is when i get on the highway reset my Trip A and myFuel Used Gauge at the same point and when i get to the end destination i check both if it says i used 5 gallons of diesel and i went 90 miles that means i was getting a average of 18mpg.......right!!!
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Old 04-09-2007, 05:58 AM   #10 (permalink)
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my DIC is right on with the 85hp predator, off when it is stock. I hand calc everytime I fill up and most weeks I do it twice
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