Author Topic: How to reset MPG, etc questions  (Read 6588 times)

Offline wal74

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How to reset MPG, etc questions
« on: August 15, 2010, 12:26:05 PM »
Hello,
I'm close to purchasing but have a few questions.  Since I don't see a reset button, how is Ave MPG calculated and can it be reset during a trip?  Or does it reset every time the vehicle is turned off or can it be saved to keep a running average MPG over several months?  Also regarding the MAFS input air temperature, is this the same reading you get in most cars for outside temp, or will this air temp be slightly off from outdoor ambient temp?

Looks like a very nice product.  If you should update the firmware in the future, can an older unit be updated?

wal74
09 Challenger R/T
98 BMW 323is
99 Infiniti G20
05 Honda Odyssey

Offline wal74

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Re: How to reset MPG, etc questions
« Reply #1 on: August 15, 2010, 12:49:12 PM »
I should have read the online owner's manual first - it answered all of my questions except for the firmware upgrade.  There is a reset command in the menu to reset the trip functions and the gauge does not re-zero when powering off.

wal74

Offline UltraGauge Admin

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Re: How to reset MPG, etc questions
« Reply #2 on: August 15, 2010, 01:44:35 PM »
  Also regarding the MAFS input air temperature, is this the same reading you get in most cars for outside temp, or will this air temp be slightly off from outdoor ambient temp?

Looks like a very nice product.  If you should update the firmware in the future, can an older unit be updated?

In order to achieve the very low price point of UltraGauge it was decided to not burden every unit with the incremental cost to support field upgrades, especially since statistically fewer than 4% of customers would every update their units.   However, should a major upgrade occur, units can be sent to UltraGauge.com to be updated at no cost for the first year.

Regarding the temp sensor, the Intake Air Temperature (IAT) sensor is different than the temperature sensor used to measure outside ambient air.  The IAT is commonly supported.   The Ambient Air gauge is less commonly supported through the OBDII interface.  When the engine is cold, the two gauges should in theory read the same, in practice we see a few degrees difference.  This is due to the variation and accuracy of the vehicles sensors

Offline wingerr

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Re: How to reset MPG, etc questions
« Reply #3 on: October 15, 2010, 01:12:07 AM »
Interestingly the ambient air temp reading from the gauge doesn't match the outside air temperature displayed on the dash, which is presumably the same sensor.

 And that's different also from the IAT gauge, which is as expected. 

I haven't tried to see which of the ambient readings is closer to correct, but they differed by something like 5 degrees between the outside air temp reading from the car vs. the ambient air temp from the UG.  And the difference wasn't consistent either, the delta varies at different times, as if the readings were from two different sensors.