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Old 03-09-2013, 01:40 PM   #26
Zaridar
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headlights flickering is only when running... havent noticed the headlights doing it anymore. since i fixed the cable...
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Old 03-09-2013, 03:16 PM   #27
Cougar4
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Well then it sounds like most of your trouble may be dealt with. The trouble with the clock may be due to a problem inside it. There is a well known problem with the solder joint connections of a surface mounted resistor that causes the clock display to go out. Resoldering the connections of the resistor fixes the problem with that. If I remember correctly the resistor number is R151 but I'm not sure of that. The problem is pretty obvious anyways. There are past posts here in this forum with pictues of the problem and the fix for it. If you don't see anymore signs of AC ripple then most likely the alternator is ok and it was just low on charge due to the bad connection.
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Old 03-10-2013, 12:31 AM   #28
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Actually had a chance to drive at night tonight... Headlights dim and brighten noticebly when ac kicks on and off still....
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Old 03-10-2013, 03:33 PM   #29
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Does it matter direction of conection of capacitor?


is voltage drop in sytsem to 12.7 acceptable?
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Old 03-10-2013, 04:23 PM   #30
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Will 1 microfarad 250 volt work?? that is the closest I could find at Radio Shack
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Old 03-10-2013, 05:12 PM   #31
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Yes, that will work. Hopefully it is non-polarized, there isn't a plus or minus sign on it is there? If it is polarized then you need to place the positive end of the capacitor on the plus side of the battery and the negative side of the cap will connect to the positive (red) meter probe tip. The black meter lead will tie to the negative battery post. If the cap is non-polarized then you can connect it in series, in either direction. When you get into capacitors of that size or higher in value, they are generally polarized.
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Old 03-10-2013, 06:58 PM   #32
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Ok will try next time its not raining out.... Thanks! Anyone know if 12.7 v is acceptable? I have to check if does it w just fan coming on or ac comp on...
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Old 03-10-2013, 08:02 PM   #33
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Alternator charge setpoint is usually 15v. Your multimeter should read somewhere around there when you test your positive lead to the positive battery terminal, and the negative lead to vehicle chassis.
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Old 03-10-2013, 11:08 PM   #34
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If the engine is idleing and there is a good load on the charging system then having 12.7 volts present isn't out of the question. Follow the advice I gave you in post 5.
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Old 03-10-2013, 11:22 PM   #35
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Quote:
Originally Posted by Cougar4 View Post
If the engine is idleing and there is a good load on the charging system then having 12.7 volts present isn't out of the question. Follow the advice I gave you in post 5.
I did and posted my results.. but now waiting to try the ac part with capacitor..
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Old 03-10-2013, 11:27 PM   #36
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however i had all accessories on... not just lights and was losing .3-.4 v from alt to batt... it kept fluctuating though every time the ac/fan kicked on.. i will recheck and make sure it is held at 1500.. also should i only have lights on and nothing else?
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Old 03-10-2013, 11:36 PM   #37
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You could also turn the blower on high and if you have a rear defroster you could turn that on. Having all those things on at the same time will present a good load on the system.
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Old 03-11-2013, 11:30 AM   #38
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So what should be my max V drop between alt and batt with all accesories off and w all on? Or does it not matter and .2v is the max allowable difference?
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Old 03-11-2013, 11:58 AM   #39
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The voltage drop between the battery and alternator means nothing! The question is, are you able to maintain voltage at the battery when loaded?

The best way to check the system is to measure the current to the load and the current to the battery. If the alternator is keeping up, the charging system is working and you need to start look for bad grounds. A clamp on ammeter is a relatively cheap investment.
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Old 03-11-2013, 02:01 PM   #40
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Old 03-11-2013, 02:04 PM   #41
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AC voltage fluctuates from .023 the .04...... under full load at 1500 rpm voltage at the alternator is 14.65... and voltage at the battery is 14.49.....
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Old 03-11-2013, 02:09 PM   #42
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I watched the multimeter for about 10 minutes until the car was completely warmed up and Idle went down... voltage slowly drops till it hit the bottom at 12.7... it would then jump up about .3 when the AC kicked on.. and then drop to about 12.5 when the fan kicked on about a half second after the AC compressor... So with everything on its anywhere from 12.5 to 12.8v
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Old 03-11-2013, 03:59 PM   #43
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The AC voltage is OK.
You are not fully charging at idle. Is your accessory belt slipping?
Did you ever fully charge your battery after replacing the bad terminal?
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Old 03-11-2013, 07:29 PM   #44
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Looking at your last two posts here and the voltages you measured it looks to me that your alternator is just fine. You have over 14 volts at normal speed and are running around 12.6 at idle. Just what it is supposed to be. The alternator isn't capable of keeping up with a good load on the system at idle speed so the voltage drops down to the battery level. If the engine runs around 1,000 RPM that should be enough speed to get the charge voltage high enough to charge the battery.
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Old 03-11-2013, 07:50 PM   #45
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wow thats not very cool... wonder if i can get an overdrive pulley for my alt or just find another model with a smaller pulley..... this is not acceptable to me

Last edited by Zaridar; 03-11-2013 at 10:05 PM.
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Old 03-12-2013, 12:37 PM   #46
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so you're sayin that every other WRX owner has this issue and your lights dim and brighten at idle because it's only putting out 12.xx volts... as far as I was aware most vehicles should put out 14.xx v at idle???
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Old 03-12-2013, 01:04 PM   #47
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Alternators can't produce their rated output at idle speed of the engine. Its just the way it is. When you have a heavy load on the electrical system it causes the charging voltage to drop at idle and may even take current from the battery also. This really isn't a problem since the car spends most of the time moving around and there is plenty of engine speed to allow the alternator to keep up with the load. If there is a light load on the system then the charging voltage will come up a little at idle speed and may even be enough to charge the battery a little.
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Old 03-12-2013, 01:19 PM   #48
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So you are saying yes?? All your cars act ths way and cant/dont charge the batt at idle with acc. On? A fully charged batt is 12.5v....
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Old 03-12-2013, 02:16 PM   #49
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As far as the alternator action I previously described, yes. A new fully charged battery should be around 12.6 volts with no load on it. Make sure your fan belt isn't slipping, that will cause the alternator output to be less than it should be.
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Old 03-12-2013, 02:29 PM   #50
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Quote:
Originally Posted by LIChuck View Post
The AC voltage is OK.
You are not fully charging at idle. Is your accessory belt slipping?
Did you ever fully charge your battery after replacing the bad terminal?
Checked belt... Althougth I just replaced it and tensioner was maxed out....( I assumed it was tight)... the belt was loose.. apparently it's stretched out further than the max allowable tension adjustment.... I put a new belt half inch smaller problem solved
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