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1985 RX7 Electrical problems

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Old 01-17-12, 12:23 AM
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ME 1985 RX7 Electrical problems

Hello everyone I was hoping some one could help me with my RX. I was driving it to work this morning when the voltmeter buried itself into 16 and my speakers made a strange noise. I shut it off and then drove it to work. The volts when down to 12 and held. I checked the Grounds and fuses and battery cables everything seems to be fine; I purchased a wire brush to clean the connections anyway. I attmpted to drive the car home and while on the freeway I noticed my volts where dropping slowly. The volts dropped all the way to 8 and i noticed my car was losing power and my oil gauge only showed 15 lbs of pressure at 3k rpm. The car barely made it home. Now the car wont start lights barely work, and I'm not really sure where to start. I hope I didnt overheat the engine or cause any more damage by driving it home. Could someone please throw me some suggestions. As it is I'm going to clean all the grounds, but thats about all I know to do...

If I'm not mentioning an important detail please let me know. Thanks everyone for reading this.
Old 01-17-12, 12:34 AM
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20 $ says its the alternator. many of my old cars have done this. The built in ic regulator goes out, won't hold a charge. Car gets sluggish and then headlights dim
Old 01-17-12, 11:02 AM
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+1 take the alternator to AutoZone and have them check it. free

Always check the free stuff first!
Old 01-17-12, 11:18 AM
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Originally Posted by milknuggets
Hello everyone I was hoping some one could help me with my RX. I was driving it to work this morning when the voltmeter buried itself into 16 and my speakers made a strange noise. I shut it off and then drove it to work. The volts when down to 12 and held. I checked the Grounds and fuses and battery cables everything seems to be fine; I purchased a wire brush to clean the connections anyway. I attmpted to drive the car home and while on the freeway I noticed my volts where dropping slowly. The volts dropped all the way to 8 and i noticed my car was losing power and my oil gauge only showed 15 lbs of pressure at 3k rpm. The car barely made it home. Now the car wont start lights barely work, and I'm not really sure where to start. I hope I didnt overheat the engine or cause any more damage by driving it home. Could someone please throw me some suggestions. As it is I'm going to clean all the grounds, but thats about all I know to do...

If I'm not mentioning an important detail please let me know. Thanks everyone for reading this.
+3 on the alternator....the internal regulator bit ther dust, spiked your volts, then quit working....the whole time you were driving home you were driving on battery alone, and as power was used, the battery discharged, to the point that you dont have enough amps left in the battery to start the car....replace the alternator and you should be good to go.
Old 01-17-12, 12:12 PM
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Ok its off to the junkyard for a new alt. Thanks so much got the help guys. I'll post how the cat is doing after I get the new alt in.
Old 01-18-12, 06:28 AM
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Since you need a new one, consider getting the GM 105 amp model. That would be a great upgrade, and is usually cheaper than the mazda models.

Just a suggestion....
Old 01-18-12, 01:53 PM
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Exact same symptoms mine had when the alternator went out.
Old 01-24-12, 02:32 AM
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Originally Posted by DerrickS
Since you need a new one, consider getting the GM 105 amp model. That would be a great upgrade, and is usually cheaper than the mazda models.

Just a suggestion....
Is that a direct bolt-on? That's the first time I've seen that suggestion....and I like it.
Old 01-24-12, 06:08 AM
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Not quite direct, but easy enough to do. Do a search on it and see. Basically involves swapping the v-belt pulley to the GM unit, and wiring in a pig-tail that is apparently standard fair at auto-zone/advance/etc...

I think I'm going to go this way with mine when the time comes.
Old 01-24-12, 09:46 AM
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Yep, that's a textbook failure of the internal voltage regulator in the alt. Spiked high & cooked itself, then died; after that, you were running off your battery until it got too depleted to carry on.

Did you get a "GEN" or "ALT" idiot light at the time? If not, you'll want to check the bulb.
Old 02-06-12, 03:59 PM
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alternator update

I installed a s4 alternator and the girl fired right up. Strange thing though; she wont turn off I switch the key to the off position and the radio and ancilliary accesories power off but engine gauges and windows still work. I'm not to sure what to do at this point any help will be appreciated.
Old 02-11-12, 10:00 AM
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Originally Posted by milknuggets
I installed a s4 alternator and the girl fired right up. Strange thing though; she wont turn off I switch the key to the off position and the radio and ancilliary accesories power off but engine gauges and windows still work. I'm not to sure what to do at this point any help will be appreciated.
Sound like you might have the alt wire wired up wrong or a wire in the wrong spot you still have power threw your ignition with the key off. Unplug your alt it should power every thing down if I am correct. The other possibility is your ignition switch but power probing would have to be done to check. Basically it's a system or wire that is applying power to those systems from the sound of it.
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