I just started a thread about problems with my fuel system. I've also got a electrical problem and didn't want to mix up the issues. First off my battery's tested ok and just had a full charge from Pep Boys. My alternator is a factory replacement from Auto Zone. I've only had it on the car for a few months but I've had it for a few years in a box. I've got a new 93 mustang starter as well. Just installed a new fat ground wire to the frame and my hot battery cable is in great shape too. I replaced the voltage regulator not long ago either. I have a pretty big Black Magic electric fan but other than that I don't have any electrical drains. With the switch off its reading slightly above 12V. When I start the car its really sluggish to turn over almost like the battery is dead. With it idling around 1k the voltage on the battery slowly climbs up to 13.5ish volts. BUT as soon as I start revving the motor the voltage drops back to just above 12V. I would think this starter had plenty of torque to turn over my motor, stock shortblock 302 with iron GT40s milled .05". I'm just guessing but prob around 9:1 compression. What size battery are you guys running? Cranking Amps, etc? Thx for any help.
You may have more than one problem.. The voltage is a little low you need to check the output at the alternator at 1000rpm you should have 13.8 to 14.2 . Is your elect. fan running ? If so you may not have the proper amperage output ? It you are using a 65 to 70 amp alternator it will not be the proper output to run a elect. fan you will need to step up to a higher output alternator 100 amp min. Jay
I suspected as much, do you know a car model I could tell the parts store to pull up to find a higher output alternator? It looks like the stock one is only 61 amps.
i think mid 80s ford trucks used a higher amparage alt with a external regulator that will directly replace the mav alt. i recomend geting a 3g alt and get rid of the votage regulator. or you can get a one wire alt and its simple to wire in. the 93 start should crank your motor over with ease. do you have it wired corretly. you should have a 2 gage or biger comeing from the positive post on the batery to the big post on the starter. a 4 to 8 gage wire from the positive post to the post on the solonoid that the bat cable used to goto. then from the other large post run a 10 - 12 gage wire to the small terminal on the starter.
Summit have the G2 alternator on sale for $85. It is a true 1-wire hookup. http://store.summitracing.com/egnse...94908331+4294908395+4294755833+115+4294880774
Ford 1G alternators are rather weak items. IMO, they should be sh!t canned immediately. Another alternative is a GM unit (gasp!). A reworked 10SI or stock 94 amp 12SI will work great. You just have to drill out the bolt hole and change the spacer length. As far as "1" wire set ups...well I tried that route and didn't much care for the results (think under drive pulleys and forgetting to rev the engine up to start the charging =...long walk home.) http://www.madelectrical.com/electricaltech/onewire-threewire.shtml
