Why does the Juice Box mess up the mileage calculation on the onboard computer?


I run the truck pretty hard most of the time and I put 80% of the miles on it with the cruise set at 80+. Without the Juice box I average 16-16.5 mpg and the computer is usually close. WITH the Juice box the computer says 19.9 almost always. I can leave it for 5 or 6 tank fulls of fuel and it will get to 19.9 or 20.0 and stay.


How is the Juice box tricking the computer?

the truck runs the same with less fuel.. it thinks. You take the performance level above range X which is stock. You get it to stock X with less pedal and hence, less fuel, according to the PCM

the truck runs the same with less fuel.. it thinks. You take the performance level above range X which is stock. You get it to stock X with less pedal and hence, less fuel, according to the PCM


Mine does the same thing, but I disagree with the above since the PCM measures fuel in and returned, so it doesn't matter what the pedal input is showing. Good question for Edge however.

the truck runs the same with less fuel.. it thinks. You take the performance level above range X which is stock. You get it to stock X with less pedal and hence, less fuel, according to the PCM





It thinks it is using less but it isn't.?.?.... the mileage is about the same with or without the box.

I am interested in how this works as well. I've often wondered if modules like the Edge and Banks "totally fool" the ECM on how much fuel is actually consumed or whether the ECM still gets an accurate reading on fuel consumption.


Like duramaxtom said, good question for Edge.

My understanding is the edge adjusts the pulse width for the injection events. This means for example the computer thing it is going for (I made up this number) .12 ms and the edge extends it to .14 ms. The computer would estimate the volume of fuel dispensed for .12 ms based on the current rail pressure and the flow rate of an injector. Since the computer doesn't know about the additional .02 ms, more fuel is injected in this extra time than the computer knows about.


Someone more knowledgeable should either confirm this or tell me why this is wrong but it is my current understanding.

what your not seeing is that the Juice 'interferes' with the signal AFTER the PCM see's it. There for, the pcm has no idea that the Juice is there, let alone tampering with the fuel pulse width. And the PCM does not monitor return fuel rate

Odd as it may seem, I have the banks stinger TLC kit which has the Ottomind (not the 6 gun) and I consistantly get accurate readings from the DIC vs. what I measure by hand! It's usually right on the money or off by only +/- .1 Plus I love the way it handles our 5th wheel.

Do all the boxes that plug in to those two main connectors skew the results, or just Edge??