1987 mustang t-top v8

wolf39us · Jul 25, 2008

ok this car is getting on my nerves...I just had a CAT installed and e-brake fixed and exhaust leak fixed and idling issue fixed and the car sounds great and all...when it STARTS

it has been running for the last 2 months perfectly fine!! I was driving it every 3 or so days

now keep in mind that before everything was done...I had a starting issue because of low voltage and something was draining the battery

just today (after 1 week of no driving) I went to the car to start it up (mind you I was late for work and I took the tops off and everything) and NADDA ZIP ZILTCH ...just a little click and then the alarm sounded really like it had seriously low voltage...

needless to say the car was unable to start and I had to jump into my '00 convertible

I need to find out why this is happening or I'm gonna go crazy!!

HISSIN50 · Jul 25, 2008

Go over all of the glovebox, vanity, trunk and other lights on the car to be sure they're not staying on constantly.

Have the charging system tested once you charge the battery up. Parts stores often do it for free.

If it tests ok, put a DMM in series between a disconnected negative battery terminal and post and note the parasitic current draw. It should be less than 50 mA. Start pulling fuses till the readings goes down. If that doesnt make the reading change, start disconnecting fusible link circuits from the solenoid's starter post till it drops. Then disconnect the alternator charge cable. In doing all of that, you should eventually disconnect the parasitic circuit. Once that's found, dissect said circuit till you find the source of the short or draw.

Good luck.

wolf39us · Jul 27, 2008

haha ok ...so yesterday I went to advanced auto and had them play around with my old battery...the crank amps came out good...but after 30 minutes it tested bad....so guess what...3rd battery in the trash...and $77 later I have a new battery! hooked it up...car starts wonderfully again...so now anytime I shut the car off, I pop the hood and disconnect the negative lead

I pulled my whole house apart looking for my Multi-Meter...I CANNOT find it...

they are only 10 bucks but I might just borrow my Grandpa's lol

anyway I guess as soon as I get a MM I will start doing the fuse test!

2BADSTANGS · Jul 27, 2008

Have the alternator tested too, if one of the diodes goes bad, it will draw current when the engine/ ignition are off and kill your battery. (mabye why you've gone through so many batteries) A simple way to test this is to turn your car off and pop the hood. Go to the back of the alternator, take a screwdriver (or another metal object that can be attrected by a magnet) and touch it to the center of the back of the alternator. If it "sticks" like its being magnetically attracted, it means that current is still flowing through the windings of the alt. This usually means one or more of the diodes are bad and the alt. is drawing current when it should'nt. I know it sounds a like "redneck mechanics" but you dont even have to pull the alt or disconnect any wires and you can diagnose the issue.

1987 mustang t-top v8

wolf39us

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HISSIN50

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2BADSTANGS

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1987 mustang t-top v8

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