need some help please
10-13-03, 05:54 PM
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need some help please
have an 83 ltd edition, with a new alternator. car was running at 13.6v up until today, got in started it and it pegs all the way to 16v at idle. so i checked the battery with my voltmeter and its showing 17.6v at idle. it lookes like the battery is original along with the cables(all corroded, pretty bad shape) what i would need to know is through process of elimination, what causes overcharging? and what should i start with first. i had the same problem with my 68 mustang, voltage reg. kept overcharging, put a one wire alt and never had a problem. thanks for any help in advance
10-13-03, 06:15 PM
#2
84SE-EGI helpy-helperton
This is most likely your voltage regulator. Depending on your model year, you may either have a voltage regulator which is built into the back of the alternator, or you may have a remote regulator mounted somewhere inline to the battery main for charging. Either way, you'll need to get this replaced fairly quickly to avoid problems with boiling out your battery (due to overcharging when running), and potentially causing other problems with your electrical system.
If you take the alternator out and to your local parts store, they should be able to hook it up to their load tester and tell you whether it's running correctly, or if the voltage regulator is functioning as designed. If not, you may need to buy another alternator. HTH,
If you take the alternator out and to your local parts store, they should be able to hook it up to their load tester and tell you whether it's running correctly, or if the voltage regulator is functioning as designed. If not, you may need to buy another alternator. HTH,
10-13-03, 06:57 PM
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yea, i was afraid of that. so corrosion on the battery and cables being old would more than likely cause a drain in the battery, i.e no decent connections, like not having a good ground and what not?
10-14-03, 03:31 PM
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84SE-EGI helpy-helperton
Corrosion on the battery (terminals) would usually exhibit itself in the form of slow starting (slow cranking), or an intermittent ability to want to crank. Sometimes this gets you the dreaded 'click-click-click' of a starter solenoid that's whacking against the flywheel but not enough juice to turn the motor.
Cleaning the terminals and applying conductive electrical grease usually fixes this up pretty quickly if the battery is still in good shape. Having a bad connection here can cause other problems, however, such as an alternator going bad at being overloaded trying to charge the battery in spite of bad connections. Your alternator will have a heavy load on it trying to overcome the electrical resistance of the crappy connectors, and may overheat or blow out the voltage regulator (very common on Infiniti Q45's, my other car).
As to the engine grounds - I've heard that the 3rd Gen guys sometimes fix idle problems by adding or replacing engine grounds - this is entirely possible, since the electricity to power critical engine components that are grounded (like your alternator) will take the path of least resistance - if that path is isolated due to a poor ground and engine mounts, then it has to go through somewhere else, increasing overall resistance, and decreasing ground carrying capacity.
The engine on your 1st gen is grounded out to the starter motor, so you shouldn't have a problem here unless you also have starting problems (as in a bad starter). HTH,
Cleaning the terminals and applying conductive electrical grease usually fixes this up pretty quickly if the battery is still in good shape. Having a bad connection here can cause other problems, however, such as an alternator going bad at being overloaded trying to charge the battery in spite of bad connections. Your alternator will have a heavy load on it trying to overcome the electrical resistance of the crappy connectors, and may overheat or blow out the voltage regulator (very common on Infiniti Q45's, my other car).
As to the engine grounds - I've heard that the 3rd Gen guys sometimes fix idle problems by adding or replacing engine grounds - this is entirely possible, since the electricity to power critical engine components that are grounded (like your alternator) will take the path of least resistance - if that path is isolated due to a poor ground and engine mounts, then it has to go through somewhere else, increasing overall resistance, and decreasing ground carrying capacity.
The engine on your 1st gen is grounded out to the starter motor, so you shouldn't have a problem here unless you also have starting problems (as in a bad starter). HTH,
10-15-03, 04:50 AM
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ill take the alt. off this evening so i can get it tested, i did a search on the parts house website and it lists a small voltage regulator for my 83. how is this possible if my alt carries an internal v.r? its not like the one for a 79, much smaller. but i agree, even though the alt. is a year old its still a rebuild. those go south pretty quick
10-15-03, 04:38 PM
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alright, bear with me while i am learning the functions and know how of the rotary motor. did not have time to take the alt. to get tested but i did do the old standby of taking the cable off while running. it still ran but was still pegged at 17 volts. can the v.r go bad in the alt. but the diode not and still keep the car running? i know its withjin the alt because it still pumps out 17 .6 volts. thanks for any input
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10-15-03, 06:16 PM
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ok took the alt. off and its stamped "mitsubishi japan" and has what looks like the mitsubishi logo, i assume this is not the correct alt. for my "mazda" (key word being mazda) anyway im taking it in to get tested.
10-15-03, 11:37 PM
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Mitsi made alternators as OEM equipment for a lot of auto companies. I don't believe there is an actual factory-produced mazda-stamped alternator for the 1stgens. How did the test go? 
10-16-03, 01:19 AM
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Of the four theoretically stock alternators I've seen on these cars, all have been Mitsubishi alternators, so I don't think there's any worry there.
Brian
Brian
10-16-03, 12:53 PM
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84SE-EGI helpy-helperton
When replacing alternators, you MUST disconnect the battery terminals from the battery to avoid burning out the diode during installation. You may think that the 'factory rebuilt' alternators that you're using are bad, but this may be caused by not disconnecting the positive AND the ground before installation.
From there, it is pretty straightforward installation, 2x14mm nuts and bolts, and the 10mm connector nut on the back of the alternator for positive and white plastic connector for ground and power leads.
All Mazda cars use Mitsubishi alternators and other parts, including coils, ignitors, distributors and other parts that are subcontracted out in the Japanese market. This is quite common, as a car manufacturer won't want to have to make each of these subcomponents by themselves just to put a car together. HTH,
From there, it is pretty straightforward installation, 2x14mm nuts and bolts, and the 10mm connector nut on the back of the alternator for positive and white plastic connector for ground and power leads.
All Mazda cars use Mitsubishi alternators and other parts, including coils, ignitors, distributors and other parts that are subcontracted out in the Japanese market. This is quite common, as a car manufacturer won't want to have to make each of these subcomponents by themselves just to put a car together. HTH,
10-16-03, 06:33 PM
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man, the alt. was so bad that the tester at the parts house could not finish the test. the diode was shown to be ok, but when he went to do the v.r test it would act like it tripped a breaker. thought the guy didnt know what he was doing so took it to another and the same thing. sure is different getting an alt for a 68 stang and a 70 1/2 falcon pricewise
alt for stang or falcon---$16.00 motorcraft w/core
83 r-x7------ $54.00 rebuilt w/core
but of course you all knew this, hehehe
can afford it tomorrow though
alt for stang or falcon---$16.00 motorcraft w/core
83 r-x7------ $54.00 rebuilt w/core
but of course you all knew this, hehehe
can afford it tomorrow though
10-18-03, 04:08 PM
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ok heres an update, put a new alternator from a datsun(same setup, $20.00 cheaper, made by hitachi)and its putting out 14.29v at idle. pulled the dents with a come along and a 5lb dent puller,and bondo. then to top it off went to the salvage yard today and way in the back i found an 82 fb and it had all the red carpet in the back, also i got the pass. side door panel. drivers side wasnt there until i dropped a screw and reached under the car to get it and whaaaaat, there was the other one wrapped in plastis. some ones going to be pissed.
