Average MPG Erases
Thread Starter
Racer
Joined: Sep 2006
Posts: 389
Likes: 1
From: Roswell GA
Average MPG Erases
Recently my Average MPG gets recent when the car sits overnight or during the day. Trip A and B stay the same though. And I think the average MPH resets as well.
Has anyone had this problem where the memory is lost?
It seems to be related to the cold weather. Maybe a battery that is weakened by the cold?
Has anyone had this problem where the memory is lost?
It seems to be related to the cold weather. Maybe a battery that is weakened by the cold?
Le Mans Master
Joined: Feb 2002
Posts: 6,937
Likes: 21
From: Waldorf MD
I posted this last week. It means your battery is going bad. Get it load tested, it will fail. Your memory is lost when your voltage falls below 8.5 volts while cranking (starting) your engine.
I measured 7.7 volts while starting and my 850 CA battery only load tested at 225 CA. 5 year old Exide Orbital, replaced with Optimal Red Top, now MPG stays in memory.
Here is my post:
http://forums.corvetteforum.com/show....php?t=1865583
I measured 7.7 volts while starting and my 850 CA battery only load tested at 225 CA. 5 year old Exide Orbital, replaced with Optimal Red Top, now MPG stays in memory.
Here is my post:
http://forums.corvetteforum.com/show....php?t=1865583
Last edited by Oldvetter; Nov 27, 2007 at 09:53 PM.
Drifting
Joined: Dec 2005
Posts: 1,720
Likes: 3
From: East Hampton CT
Grounds can affect this too.
I have this problem every winter. My optima red top has plenty of cranking power, however the normal parasitic draw of a C5 overnight in the winter seems to push it over the edge sometimes.
Here are some observations:
-If I leave a battery charger on overnight, the avg will be retained.
-If I leave the door open when I turn the key to ON, it will lose settings
-If I start and stop the car a few times (bring it out, wash it, put it back away, etc) and don't let it charge for >15min) the settings will likely be lost the next time I start it. Starting voltage is around 10.8-11.5 according to the DIC after a few quick start/stops, but normally 11.9-12.1 if properly charged.
-The problem is twice as bad in the winter. My car is a daily driver here in CT and I drive it 4-5 out of 7 days but the problem is definitely worse in the cold weather.
I have this problem every winter. My optima red top has plenty of cranking power, however the normal parasitic draw of a C5 overnight in the winter seems to push it over the edge sometimes.
Here are some observations:
-If I leave a battery charger on overnight, the avg will be retained.
-If I leave the door open when I turn the key to ON, it will lose settings
-If I start and stop the car a few times (bring it out, wash it, put it back away, etc) and don't let it charge for >15min) the settings will likely be lost the next time I start it. Starting voltage is around 10.8-11.5 according to the DIC after a few quick start/stops, but normally 11.9-12.1 if properly charged.
-The problem is twice as bad in the winter. My car is a daily driver here in CT and I drive it 4-5 out of 7 days but the problem is definitely worse in the cold weather.
Tech Contributor
Joined: Dec 2003
Posts: 19,384
Likes: 87
From: Horncastle Lincolnshire, England
2023 C5 of the Year Finalist - Unmodified
I posted this last week. It means your battery is going bad. Get it load tested, it will fail. Your memory is lost when your voltage falls below 8.5 volts while cranking (starting) your engine.
I measured 7.7 volts while starting and my 850 CA battery only load tested at 225 CA. 5 year old Exide Orbital, replaced with Optimal Red Top, now MPG stays in memory.
Here is my post:
http://forums.corvetteforum.com/show....php?t=1865583
I measured 7.7 volts while starting and my 850 CA battery only load tested at 225 CA. 5 year old Exide Orbital, replaced with Optimal Red Top, now MPG stays in memory.
Here is my post:
http://forums.corvetteforum.com/show....php?t=1865583
