Battery volt reading
Thread Starter
Intermediate
Joined: Feb 2013
Posts: 27
Likes: 0
Battery volt reading
When turning the key from OFF to ON the gauges do their sweep and then go to their respective values. When I watched battery voltage today it slowly ramped up to just under 13 volts. I mean slowly. This is a new fresh charged battery. Then when I cranked the starter it pulled the voltage down to approximately 8 to 10 volts. Today after battery installation it clicked once then fired right up. First time it happened. Usually pops right off. I'm using a standard 5/16 short combo wrench to tighten the cables. Maybe I'll see if I can torque the posts to 8ft/lbs which is what the battery manufacture specifies. What are you seeing on your in car voltmeter when turning to ON fast or slow meter ramp up?
Thanks
Thanks
Le Mans Master
Joined: Sep 2003
Posts: 8,847
Likes: 794
From: Longview Texas
My display shows voltage immediately, but does read .5 volts lower than at battery terminals... I would make sure grounds and all connections are tight...
Have you tried reading the actual voltage across the terminals?
Have you tried reading the actual voltage across the terminals?
Melting Slicks
Joined: Feb 2001
Posts: 2,791
Likes: 355
From: Northville, MI
Your battery needs 12.5V or more to start and control all the electronics correctly. Remove the battery cables and using a VOM measure the voltage at the battery. You can charge you battery but once you remove the unit you are to the base voltage. Less that 12.5V and you encounter hard starting, the dreaded column lock problem, and other gremlins. I pushed my OEM battery too many years and even with the CLB installed still enabled the column lock-fuel cut off problem.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
The DIC Digital Volt meter and the analog voltage gage do NOT read actual battery voltage. They read the battery voltage after it goes thru the IGNITION SWITCH!
Your ignition switch has 5 main contacts inside and those 5 contacts can get carboned and burnt. The resistance caused by the damaged contacts is what you are seeing.
Here is a detailed post that explains it all and how to fix it:
- C5 ignition Switch repair - http://forums.corvetteforum.com/c5-t...ch-repair.html
If the switch contacts get bad enough, it can affect proper module operation, fuel pump output and cause all kinds of weird DTCs to set.
Bill
Your ignition switch has 5 main contacts inside and those 5 contacts can get carboned and burnt. The resistance caused by the damaged contacts is what you are seeing.
Here is a detailed post that explains it all and how to fix it:
- C5 ignition Switch repair - http://forums.corvetteforum.com/c5-t...ch-repair.html
If the switch contacts get bad enough, it can affect proper module operation, fuel pump output and cause all kinds of weird DTCs to set.
Bill
Thread Starter
Intermediate
Joined: Feb 2013
Posts: 27
Likes: 0
A voltage drop across dirty contacts is normal. I'm not concerned with that. I read 12.72 across the battery measured with a calibrated Fluke 87. The battery is one month old and fully charged before install. I'm going to look at the connections bat+ to fuse box, bat+ to starter. Plus I'll torque the posts to the manufacture specified torque. If I can get my 1/4" torque wrench in there.
Ps. This is a great forum. People like Bill and others spent a lot of time with these cars. Much appreciated. This is my first C5. Got a C4 to.
Thanks
Ps. This is a great forum. People like Bill and others spent a lot of time with these cars. Much appreciated. This is my first C5. Got a C4 to.
Thanks
