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i put in a universal ford painless system in a 72 mach 1 351 cleveland. the wireing has gone pretty well for as little electricial experience i have. i also have a msd ignition box and msd billit dist. i have the alt. hooked up the way the manual tells me then i fire it up and drive it and it goes dead within 15-20 min. i have also noticed that when i hook up the main terminal a small arc happens. does this mean i am drawing power from somewhere? please help me i just want to be able to drive it without getting jump started! any help would be greatly appreciated. Dylan
 

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I would say you have a short somewhere, even without the alt not charging, on a charged battery you should be able to run longer than 15-20 min, you need a VOM or DVM (volt, amp, ohm meter of some type), first to determine if you have a short drawing power, remove the pos battery terminal and place the ammeter side of the meter in series, this means the pos lead of the ammeter goes to the POS battery post and the neg lead of the ammeter goes to the POS battery cable end, if it reads anything other than a few milliamps, your battery will run down, the greater the draw the faster the battery will be discharged. If this is okay, then you just have a charging problem, double check the wiring to the alternator and the regulator, here's a link to a wiring diagram Wiring & Vacuum Diagrams - Mustang tech and info links.
 

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Here is the way to check your charging system. You need to use your voltmeter to check some places, this is for a system with an external regulator, the big red terminal on the alternator should run to the solonoid (battery side) it should have the same voltage to ground at both places without the engine running the A terminal on the regulator should have battery voltage also, the F terminal on the alternator should have 6 -14 volts with the engine running depending on the load and the charge on the battery and the temperature, the S terminal of the regulator should have battery voltage with the ignition key on (not accessory). If there is no voltage on the F term of the alt, shut the engine off, disconnect the battery neg term, and unplug the connector from the regulator, reconnect the battery and start the engine, use a piece of copper wire, and jumper the A terminal of the connector in the wiring harness that was removed from the regulator to the F terminal of the connector of the wiring harness (that was removed from the regulator, this will bypass the regulator and put full battery voltage on the field of the alternator making it put out maximum output, if you connect the voltmeter to the battery terminals you should see the voltage rising indicating it is charging, this is only a test, it cannot be left this way the system voltage will exceed 17 volts. If this test was successful, then you are half way there. Then shut the car off, disconnect the battery, remove the jumper wire, reconnect the connector to the regulator, reconnect the battery and start the car once again, now measure the voltage on the S terminal of the regulator, it should have battery voltage around 12-14 volts, if it has no voltage then that is why the regulator is not turned on, the S terminal could run to the ignition side of the ignition switch. Post your results. Good Luck.
 

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One quick way to determine which circuit is the culprit for the constant drain is to remove fuses one at a time. With each fuse, check for that arc you mentioned. When you no longer get the arc, you have located the circuit you must trace/fix.

Replace each fuse as you go. If you get the arc on each one, then you have a drain on more than one circuit. If this is the case, you can use the multi-meter to determine which ones are draining. Simply remove the fuse and bridge the terminals in the fuse box with the leads of the multi-meter. Read your amp draw. If it is zero, then that circuit is fine. Make sure the doors are close when you are doing this since the interior lights will cause amp draw and may fool you.
 

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if the car is still running and the battery is truly dead then the alternator must be working car won't run with no electricity at all. have you checked your voltage regulator?
 
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