Couple suggestions.
First, its better to use an inductive amp probe if you can. That way you dont have to break the circuit to test. I understand that you may not have such a tool at your disposal.
If you have no choice but to use an ammeter in series, make sure it set to 0.00. Even at that low a setting, it may not be sensitive enough to register a draw of less than 50 milliamps
Second, the optima batteries are known for being less than stellar. I know it stays up out of the car. BUT, without properly testing it, its possible its borderline and doesnt show its azz til its in the car.
A good battery test without a load tester is to first make sure its fully charged, 12.6, install it, turn the headlights on for 2 minutes, monitor the voltage level. If at anytime it drops below 10 volts the battery is junk. If it doesnt drop below 10 volts, turn the lights off after 2 minutes, and monitor the lenght of time it takes to recover, and the voltage level it finally returns to. It should return to a voltage level of at least 12.4. Any less and its junk.
Another couple things to consider.
A 194 bulb (common interior bulb) draws .280 amps. No where near enough to drain a good battery overnight. SEVERAL of them on at the same time, equalling 2 plus amps, MAY kill one over night, but I've seen otherwise.
Basically what I'm saying is if with your ammeter you're seeing zero amp draw, or close to it, chances are the battery is shot, and it just doesnt show until you put a small load on it.
If you have access to a load tester, we call em hot dog grills , put a load on that rascal and you will probably see it drop to well below 10 volts. Hope this helps
If ya need any more 'lectrical info let me know.

 

I am sorry but that tool only works with AC power.

I agree.....this is a good idea and easy enough to do.

ski_dwn_it, you may want to read up in your manual for your meter if you have not already. There are so many different types of meters out there it is hard to tell if you are using it correctly or if you are actually reading zero load on the battery when the car is not on.

Basically it is like this though......either you have a draw of some kind that you have not seen or your battery is loosing a charge on its own, you must find out which. Eliminating the battery will be the easiest. Load test it at home or take it to an auto parts store and have them test it. If it checks good, you are not getting a proper reading with your meter. Check the manual for reading current and take your readings from the positive lead. Once you see the draw there you can start hunting around the car for it.

I am interested to hear what you find out.

 

On the contrary.

Several Digital DC Clamp-On Meters are available these days
for reasonable prices. For example, less than $100 will purchase

Extech Mini DC Clamp Meter
Model DC400

 

Everybody already gave you great tips,better than I can do...but heres a long shot...is your battery cables original?

Any of them swollen,cracked,or showing signs of old age?

If so to any,I would suggest new cables to be put in,I didnt have a draw you did,but notice a power loss on start up and etc with old cables.

Hope you figure out the problem...draws are a pita to track and i removed fuses one night at a time to see what may be causing a drain I once had in another car.Never did find the ****!

 

Uh, that would be a NO. I've owned 2 pretty high dollar low amp inductive pickups for the better part of 10 years. Use them with an o-scope to do some high tech testing. Stuff like primary coil saturation, injector coil testing. Fuel pump testing. Very cool, stuff.

I also have a separate/dedicated one for AC.

This is why I said to make sure the meter is reading 0.00. If its reading to the hundredth, it should pickup any amount of draw. If the meter is accurate. And bein a fluke it ought to be.
And this is why I told him to load test the battery with the headlights. Without a good load tester, this is the best way to load test a battery. After 2 minutes with a 7-8 amp load (average headlight draw on lowbeams) the battery should recover to at least 75%, which is 12.4 volts. Just because a battery has 12 volts doesnt mean its good. I've seen em 12.2 at rest, and as soon as you hit em with a load they're down below 10. Charge, remove surface charge and retest, same thing.

 

I spoke too quickly.....please excuse me.

 

No problem.

 

Does the car have the bose audio system?
Possibly the bose relay behind the dash.

 

Well fellas today I got a new optima for it. Took it into Autozone and told the guy to test it. They load tested it and said that it was borderline, plus out of warranty.

However, as the manager put it....you are in here enough to own the place, so go over and get a new one, and told the kid to give me it for free and put a new warranty on it starting today!! Told me he doesn't wanna see me get to the track and have a problem.

Told him he did not have to do that - and he said not to worry Put this one on the load tester and it did not even hardly move compared to my old one.

Anyways I am going to pull all the fuses that I do not need....since I am running the DFI most all of them are useless anyways - vats, injectors, so on....maybe of them will be the one that was draiing it or all along it was just the battery. We shall see.....thanks a million for all the help.

 

keep us posted, brah...

 

I was wondering, couldn't he pull the fuses one at a time and replace them with the meter set to read amps or milliamps as the case may be, and then find which circuit is drawing his power in more than the 20 milliamp range. This would narrow it down considerably. Or am I misunderstanding the use of a multimeter in some way?

 

Jesse, had the same problem and it turned out it was the Bose relay behind the breadbox as noted above.

 

Anyone?

 

My vote is that, aside from requiring a DMM, this approach would identify
the circuit with the drain just as well and would perhaps be a little
faster.

Once the circuit was identified, it would still be necessary to trace
the draw within it.

.

 

Your Fluke VOM is perfectly capable of measuring your leakage current but not on the 10 amp scale! Use the 400 Ma scale with your probes plugged into the right two sockets (ground and +V/ma). Pull the courtesy light fuse and put the hood down or unplug the hood lights. Remove the negative cable from the battery and connect the Fluke between the neg batt terminal and the neg cable. GM says leakage should not exceed 50 milliamps, my 87 draws 27 ma. If your Fluke still shows 0 ma. take the case off and pull the 400 ma. circuit fuse, if it is blown, your meter will always show 0 ma. Replace the blown fuse.
Before you measure leakage, at night check for underhood lights, vanity mirror lights, door panel map lights, center console light. Do not leave your key in the ignition parked because you keep the anti-theft circuit on. Do you have a radar detector, aftermarket radio, alarm, audio amplifier? Check em!
If your leakage current doesn't exceed 50 ma. you have a battery that won't hold a charge and should be replaced. If well over 50 ma. , start pulling fuses one at a time while watching the ammeter, a dramatic drop will tell you what circuit requires further investigation . Behind the battery is a jump start bolt, remove the nut and remove one at a time, the 8 wires while watching your ammeter. There are some other circuits that have circuit breakers and these breakers I believe can be unplugged. Charge the battery up and connect the batt cables, after a while, feel the seat adjust motors for warmth, these are on circuit breakers and we have had C4 posters that had defective seat switches keeping one motor on which rapidly discharged their batteries. Let us know what you find.

 

To answer your question- Yes, he could do this. But his current problem might be before his fuse box. Most of the earlier gen vettes have issues with capacitor breakdown(aka-Leaky caps). I just put a master on off switch at the battery. I don't have the time or resources to replace every electronic capacitor in my car.

 

Here's another possibility based on my experience. If you have sport seats, there is a constant power supply to the rocker switches that control the lumbar pump, recline and side bolsters. One of my switches fell apart inside and caused a short. Although the breaker in the fuse box did it's job, it would cycle on and off and eventually kill the battery in about 6 hours.

 

Its problems like this that are hard to find. Using an inductive amp probe and a graphing DMM/o-scope makes it alot easier. Again, its having the right tools and resources to make the job easier.
That being said, even after you graph the intermittent draw, you then have to systematically find it. Thats the hard part.

 

A drawback to cutting off current with a battery disconnect switch is that
the ECM needs to relearn engine parameters for a short period of
operation after the battery is reconnected. There is also the
inconvenience of operating the switch, not to mention the expense and
labour to install it.

As a matter of safety in case of an electrical fire, I have one of these
switches from Mid America. Understand that the memory bypass
feature must be excluded if one of these is used for the purpose of
preventing battery drain.



.

 

I spent about 4 hours saturday pulling fused and measuring load. I couldn't find any one single circuit that was loading the battery.

First battery was purchased 9/06 and went dead, second 01/07. After testing every circuit, I brought the battery to autozone saturday night. They charged and tested it. Junk.

I put a new battery in yesterday morning (sunday), fired the car up and brought it to my house from the shop. Let it sit, went to Boston for the day, came back and fired it up last night. Drove to Salem, shut it down. Fired it up an hour later, drove to the video store, shut it down, fired it up 20 mins later. It appears to have solved the problem.

That wouldn't bother me soo much as I run open-loop only. I spent more than enough time trying to get closed loop working 'properly' with my cam, and I gave up.

-- Joe