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-   -   electrical drain.... please help electrical guru's (http://forums.mustangworks.com/showthread.php?t=47966)

BowTie Eater 5 Liter 03-02-2006 01:42 AM

electrical drain.... please help electrical guru's
 
well ive been having nothing but problems with my 91 lx 5.0. its killing batterys like no tomorrow. well, here is what i did, i disconnected the neg(-) cable from the battery, and tested the volts between the (-) terminal on the battery and the neg. battery cable. well its over 12v, so i decided to pull the fuses one at a time to see if i could pinpoint the drain. well after an hour of dicking around, i could not find it, i pulled all the fuses in the fuse box, disconnected the alt. cable that goes to the pos. side of the battery, and still, i have a 12+ volt draw. anyone have any clue where else to check?

this is the only thing i can see being my problem, ive tryd so many things with no luck, went through 2 batterys, car still wont start when warm(it cranks over so slow you would think the battery is dead).

any electrical experts have any ideas of where else to check???

much appreciated!!!

BowTie Eater 5 Liter 03-02-2006 02:15 AM

Re: electrical drain.... please help electrical guru's
 
im going to ask just for stupidity sake, did i have it on the right setting, and was it supposed to be on the pos. side of the battery i was supposed to check???

bigred90gt 03-02-2006 02:28 PM

Re: electrical drain.... please help electrical guru's
 
Crank the car, and test the voltage at the battery while running. I would check the pos lead to the pos side of the battery, and the neg lead to a chassis ground. It should be around 14 or 14.4 volts. Then turn the headlights on and check if it drops. If so, pull your alternator and take it to a parts store to have them test it. They test them for free. It sounds to me like your alternator is in need of being replaced.

John Del 03-02-2006 05:14 PM

Re: electrical drain.... please help electrical guru's
 
Quote:

Originally Posted by BowTie Eater 5 Liter
well, here is what i did, i disconnected the neg(-) cable from the battery, and tested the volts between the (-) terminal on the battery and the neg. battery cable. well its over 12v,


Here's what you're missing:

The meter you are using doesn't draw enough current to use that way. In other words, it's a high immpedance unit. You should use an ammeter in line to measure current draw, and compare readings to the manual's suggested value. You can also use a "test light", which will draw current. Put the test light (or plumb in a turn signal lamp) between the battery post and cable (you can use either pos or neg). You can then start pulling fuses and disconnecting stuff until the light goes out (or goes dimmer).

You'll find that when the car is fixed, using the volt meter as you were doing will still show 12 volts drop because of the EECs normal standby current usage.

John

BowTie Eater 5 Liter 03-02-2006 10:04 PM

Re: electrical drain.... please help electrical guru's
 
well thanks for the help all. we tested it and it is my starter, its drawing way too much power(especially when hot), going to replace it tomorrow with a gear reduction starter, and possibly make a heat shield, everything else is fine, no electrical draws

Coupe50h 03-04-2006 03:19 AM

Re: electrical drain.... please help electrical guru's
 
It usually is'nt a draw, i thought the same thing about my car, I suspected it was the alt, startr, bad ground ect....the problem was right in front of me all along, the battery.
Yes the parts store said it tested good? twice!! I finally bought an optima red top battery, my car starts better and faster now then ever.....thought id share that
Take it easy..


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