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#1066303 - 05/06/20 12:28 AM parasitic battery drain HELP!!!  
Joined: Jan 2005
Posts: 131
8T7AERO Offline
Member
8T7AERO  Offline
Member

Joined: Jan 2005
Posts: 131
Corona, CA
Hello I need some help and advise on trouble shooting a parasitic drain on my battery after the car been sitting for a couple of days, Its ruined 2 Optima redtop batteries (one brand new and the other was out of my other car, so bad that it wouldn't take a charge) The Monte has the ECM removed and the harness that goes with the removal of it. Wondering it that could be a cause it? I thought of using a millimeter connected to the battery and pull the fuses one at a time to see if the load on the battery car not running drops? I also have a MSD ignition (box,coil and distributor), electric fans with a relay and a torque converter lockout switch installed ,which was just installed prior to getting the car running about a month ago and Its was sitting since 2014 the garage. I checked the the charging system and grounds and checked out good, prior to realizing that it might be a parasitic problem. Thanks


87 Aerocoupe,Rapp Racing 383.Leather interior. headers, flowmasters, k&n filter,MSD Ing, 17x8 iroc w/ 245/45/17 s.s.b.c.calipers & cross drilled rotors. Kenwood sound system..
#1066309 - 05/06/20 08:14 AM Re: parasitic battery drain HELP!!! [Re: 8T7AERO]  
Joined: Feb 2008
Posts: 795
AkronAero Offline
10+ Year
AkronAero  Offline
10+ Year
Member

Joined: Feb 2008
Posts: 795
Akron OH
If you have a volt-ohm meter, pref with DC amps, you can disconnect the battery and start taking measurements through the meter. Start with the lights in trunk, under hood and glove box; disconnect and look for change when bulbs removed and closed (before/after). I think my MSD had a draw too, so I put in a disconnect on the battery ($15). Swapped out so not sure now. You can check for a bad diode in your alternator which will allow a continued drain when shut off. You can also try to isolate portions of the fuse box or related circuits but its a lot of effort. Like to hear OP experiences too.
Good hunting.
Gordon

#1066312 - 05/06/20 03:03 PM Re: parasitic battery drain HELP!!! [Re: 8T7AERO]  
Joined: Apr 2011
Posts: 1,019
Hunter79764 Offline
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Hunter79764  Offline
Member

Joined: Apr 2011
Posts: 1,019
Grand Prairie, Tx
I had a bad diode that would kill a battery in 2-3 days on a truck I had. Installed a battery disconnect since I didn't use it much, didn't figure out the cause until I replaced the alternator because the bearings went to crap. I also had my glovebox light switch on the Monte act up and stay on, it would kill it in after a while.
Otherwise, you are on the right track. You might go in and pull a handful of fuses, then add them back in and look for changes.


Shawn

'85 MC with budget 5.3L swap, TH350 with stock 2.14 rear end
It ain't much off the line, but it's nice on the highway
#1066316 - 05/07/20 12:23 AM Re: parasitic battery drain HELP!!! [Re: 8T7AERO]  
Joined: Mar 2012
Posts: 821
MC96 Offline
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MC96  Offline
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Joined: Mar 2012
Posts: 821
St. Johns MI
Put a test light between the battery ground wire and the battery ground terminal, if it lights up pull fuses until it goes out.

That will narrow it down to what system the draw is in.


86 SS
400SBC, 4l80e, MSD Atomic injection/trans controller, Tilt glass clip, all tubular arms, corvette brakes, 9" rear
In progress
#1066318 - 05/07/20 12:59 AM Re: parasitic battery drain HELP!!! [Re: MC96]  
Joined: Dec 1999
Posts: 11,655
86ttop Offline
20+ Year
86ttop  Offline
20+ Year
Member

Joined: Dec 1999
Posts: 11,655
Brooksville, Fl
Originally Posted by MC96
Put a test light between the battery ground wire and the battery ground terminal, if it lights up pull fuses until it goes out.

That will narrow it down to what system the draw is in.



This^^^^^^


Leo Paugh
It's not an attitude, it's just the way I am.
POW*MIA
You are not forgotten
If things improve with age, I must be approaching magnificent. thumbs
#1066329 - 05/07/20 02:57 PM Re: parasitic battery drain HELP!!! [Re: 8T7AERO]  
Joined: Mar 2000
Posts: 5,538
upflying Offline
20+ Year
upflying  Offline
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Joined: Mar 2000
Posts: 5,538
Reno, NV
I have a knife blade disconnect on my negative terminal. Not that I have a parasitic drain but more for fire prevention. If I smell wiring burning, I can quickly save the car.
A quick disconnect could temporarily solve the problem until you track down what circuit is on.

Last edited by upflying; 05/07/20 02:57 PM.

86 MCSS Notchback coupe, LS3, 4L65E, QP 9", Eaton Truetrac, 4 wheel disc, column shift, Dakota Digital, silver with maroon bench interior


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