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Old 10-24-2011, 01:40 PM   #1 (permalink)
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Join Date: Sep 2010
Location: Denver, CO
Posts: 1,300

Colorado - '17 Chevrolet Colorado 4x4 LT
90 day: 23.07 mpg (US)
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Diesel EGR Defeat

I finally pulled the trigger and built my EGR defeat circuit, and installed it this weekend. I'm still tweaking the MAF output to reflect the amount of EGR flow the ECM needs to see in order to not trigger the CEL, but the hardware is now in place.

When I get it configured where I want, I will be doing ABA fuel mileage testing. I had hoped to use my Scangauge to calculate trip mileage, taking note of the following data to facilitate comparison between data sets:

Initial coolant temperature
Ambient air temperature
Miles traveled (will only be commute, with no deviations)
Average speed
Scangauge reported average MPG

Unfortunately the Scangauge doesn't like the new mod. The lack of EGR flow must be affecting how fuel use is reported. Typically on my a.m. commute I average 36mpg or so. With the EGR defeat in place, the Scangauge reported 56mpg on todays commute.

Something tells me my little device has not improved my mileage by 55%. Anyone have any ideas for the scangauge or other methods for documenting fuel mileage?

I'm not coasting, I'm shifting slowly.
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