Charging System

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Scrubman

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I have a 2000 Corvette Convertible, my problem is if the car sits or a few days it drains the battery.
Took it to the shop and the tech removed the fuse for the lumbar seat control. He stated by removing the fuse I shouldn't have any more problems. Car ran fine for 4-5 driving s, (only drive it on week-ends). Went to drive the car and once again battery was drained. Battery is appr. 2 years old.
I read in the owners manual and the voltage while the car is running is approx 14 but when car is shut off gage only reads 8.
Don't know what to do next.
 
Welcome to the motley crew.....

I would take a DVM in the current mode and hook it in SERIES with one of the battery cables, park the car as per normal, and start pulling fuses one at a time and note the current draw changes greatly with the offending circuit.....

current drain should not be over say 10-15 MA. at most.... 3-5 MA is more like it, far as I"m concerned, just enough to keep the memory on the engine control computer, and radio,

IF you have a 'Body Control Computer' and you pull that fuse, and see the drain change drastically, we go from there....I had a truck do that to me once....it was a funny fix.....

:devil::rolleyes:
 
As an example of what it can be. I had an 06 GTO, the computer had to be replaced because it wouldn't go to sleep when the car was shut down - would kill the battery in 2 days. It also killed the battery in 1 year.... took forever to get the dealership to actually test for the issue - they would simply claim it was a bad battery that was causing the no start issue.
 
ECM doesn't "go to sleep" RAM power is constant 12V the majority of the system is disabled however (injector drivers, quad drivers..blah blah blah)

Put a DVM over the batter and 12V wire and register the current draw then start pulling fuses to see what's up. It does soud like a bad battery. I've had those delcos fail on me all the time, I had about 8 of them, I think I'm down to 0 now, They all crap out rather quickly when car is not being used.
 
Twin_Turbo said:
ECM doesn't "go to sleep" RAM power is constant 12V the majority of the system is disabled however (injector drivers, quad drivers..blah blah blah)
Click to expand...

that's a clever way of taking a clear term and making it opaque?

IIRC on my computers "sleep" is a low power state where most external devices are turned off, but the settings, programs and such are maintained in RAM so that the computer can be quickly restarted....

maybe it's just with the Chinese computers I have.... :rolleyes:
 
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It's not something that goes to sleep. Most of the ECM is fed off ign. switched 12V, turn the key and it's off. The RAM power is fed off battery oltage so it is always active as long as you have a charged battery.

It's nothing like your home PC where sleep mode powers off parts off the main board because you are setting it to that mode. The ECU in the car is simply wired to a switched and a non switched source.. no sleep modes no nothing.

As such the ECU can't be stuck and not go to sleep, if it does it simply means the key was not turned off or there's a short to 12V in the ign. switched feed.

See... not the same difference and no need to roll your eyes and be disrespectful again.
 
You must be an electrical engineer.... For that reason, I get your precision in language, however, I don't get why you get all persnickety over concepts that aren't even related to the PO's original question. I used layman's language to describe a situation that was odd, and was - this according the GM techs - a failure exactly as described. While I'd love to eavesdrop on the argument you could have with them; it's totally off subject.

You may disagree with what I described as imprecise, but you understood it - and I really doubt it's the same problem - and that was the point, to be understood. To continue, my point was the issue may be an insidious problem such as what I just described. Mr. Vette prescribed testing for voltage use, which is exactly what he should do. I followed up with comment that voltage use may not be the whole story. What I said was that just because it has draw doesn't tell you whether or not that draw is what is killing his battery. Too much draw could be the issue - and he needs to test for that....

You followed up with this language game that I still don't understand how it makes a difference to what I said to the original PO or adds to the original attempt to help. As for rolling my eyes - just picture I'll be doing every time you talk to me until you ban me... and even then, your name will come up in other forums and I'll be rolling my eyes at that time too.
 
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OH PLEASE guys, this is a simple thing about CURRENT DRAW, hence the use of the CURRENT mode of a DVM in SERIES with one of the battery leads, we are not measuring VOLTAGE, but current,


we can take a VM and put it in series with a open switch, so no load....and what we measure??? NO voltage, because NO current flow....

but IF we have as much as a computer mem storage demand, we have more than the VM will need to measure voltage, and so it indicates full voltage differential.....

OP, sorry to get into this shit so deep, not to snowball you, just trying to help....

:thumbs:
 
I'm not nitpicky, you tell him it's possible the ECU does not go in sleep mode, it is impossible since there is no such thing so no need to check that or even change the ecu if he might have thought that would fix it. How is that not related? It's completely related and a valid comment.


Like I thought you hav some sort of issue with me, it started some time ago and I have no idea why but it was there in the alternator thread, you telling me I was an idiot for using powermaster alternators, then there was the head gasket thread where you read a lot more into my comment then there really was and now here. What is your problem?

I'm done with your BS, I will not comment on any of your idiotic attempts at ridiculing me but if you post BS info like douchebag boy did I will rectify as I see fit. Yes, you posted BS info with your sleep mode comment.

To the OP, if testing a 20mA draw is about normal. If it's over 4ish I would get worried. There's a lot more stuff still active w/ the key off than on older cars, (ECU RAM, keyless entry doodads, alarm system/maybe aftermarket alarm?...etc)

Is there an aftermarket alarm on it?

I would start by pulling the ign 1 & 2 fuses, they each fuse a bunch of stuff. You can quickly eliminate a whole bunch of stuff by figuring out if the draw is on either of those.
 
SuperBuickGuy said:
As an example of what it can be. I had an 06 GTO, the computer had to be replaced because it wouldn't go to sleep when the car was shut down - would kill the battery in 2 days. It also killed the battery in 1 year.... took forever to get the dealership to actually test for the issue - they would simply claim it was a bad battery that was causing the no start issue.
Click to expand...

Forgive me for being dense but this sure sounds like you are saying that the no sleep mode (which I don't think exists) is "an example of what it can be". Sorry, but this sounds like you are suggesting that this is a possibility.
 
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