How do you know if your alternator is going bad????
08-13-2003, 09:40 PM
#1
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How do you know if your alternator is going bad????
I was driving today, and I noticed that my D5 light gets dim when I come to a stop...then gets brighter once I accelerate. I do have a 2 amplifier sound system, but I also have a 1.5 farad cap. Can my alternator be going bad???
08-13-2003, 10:09 PM
#4
Mazda3 and Honda Civic in
When mine left, it was quick. Engine was wining(altenator), ac would not get cold, had a hard time starting, lost alot power(horse)
I agree w/brianlin87 I dont think its your alternator
I agree w/brianlin87 I dont think its your alternator
08-13-2003, 11:24 PM
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nah your alternator should be fine. its most likely just from the electric draw your system is creating even tho u do have a cap (which imo dont do a whole lot) but i wouldnt worry too much unless ALL your lights start dimming quite noticeably (in and out)
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08-14-2003, 05:52 AM
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Its still doing it!!!!! What could it be.......? It does it in D2-P Its similar to when you roll your windows up and keep holding the button
08-14-2003, 05:54 AM
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I remember being the first to notice this like two years ago. I even took a little video of it back then. And it's not just when coming to a stop. The brightness of the D5 light changes during driving too, depending on if it's shifting gears or if the TC is locking or unlocking, from what I noticed.
I don't think I've noticed the light dimming/brightening since I got the trans replaced though.
Might be a "feature" of the old transmission.
I don't think I've noticed the light dimming/brightening since I got the trans replaced though.
Might be a "feature" of the old transmission.
08-14-2003, 06:11 AM
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I have had he battery replaced....about 6 months ago. JRock: I do remember you posting that video....did you take it to the dealer....if you did, what did they say. Is this something normal? I hope it doesn't mean the trans is going
08-14-2003, 08:02 AM
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Based on what I understand, I do not think that it is the light going bad. My uneducated guess is that it is related to the electrical. According to what I've read, a cap may not be sufficient by itself for your power needs. A more powerful alternator with improved wiring (4 ga is what I saw recommended) may attack the problem at the source.
Again, this is TOTALLY uneducated. I'm just throwing it out there to help problem solve. I wish I could give you a definitive answer.
Again, this is TOTALLY uneducated. I'm just throwing it out there to help problem solve. I wish I could give you a definitive answer.
08-14-2003, 08:07 AM
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Nicky -
Just in case...
For alternators, I have read about this guy, Dominick Iraggi. He seems highly recommended. Do a search for his name here:
http://www.termpro.com/cgi-bin/ubb/ubbiquery.asp
I don't want to alarm you by this post. It's a "just in case" thing.
Regards, J.
Just in case...
For alternators, I have read about this guy, Dominick Iraggi. He seems highly recommended. Do a search for his name here:
http://www.termpro.com/cgi-bin/ubb/ubbiquery.asp
I don't want to alarm you by this post. It's a "just in case" thing.
Regards, J.
08-14-2003, 08:19 AM
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My car has been doing that for at least 2 years and it still drives normally. It dims whenever i accelerate. Oh and it was doing this before I intalled the pullies. i'm on the original battery still even though just to be safe I am going to change it before the winter, since it will be almost 4 years old then.
08-14-2003, 08:29 AM
#24
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Originally posted by Nicky Pass
It sounds like alot of peoples cars do it....I guess its normal
It sounds like alot of peoples cars do it....I guess its normal
Then you'll have one less thing to worry about!
08-14-2003, 08:56 AM
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Ummh, I was told not to disconnect the battery while the engine is running. Doing so will cause a fault in the ecu, at least that's what I was told
08-14-2003, 08:57 AM
#27
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Originally posted by Red-CL
Disconnect your battery while the car is running. If the car cuts off, you need a new alternator. If it stays on, your fine.
Disconnect your battery while the car is running. If the car cuts off, you need a new alternator. If it stays on, your fine.
Your battery also acts as a capacitor taking any extra load if need be. And helps noise from getting into the electrical system.
Your ECU and other circuitry can be exposed to voltage/amp spikes without the battery connected. The second you take the battery off your going to make the voltage spike.
This method would work on OLD cars that do not have an ECU/sesitive electronics...
Go get your alternator tested at the dealership. They have a unit they connect to simulate loads and test the regulator/coils.
08-14-2003, 09:09 AM
#29
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I didn't relaize this would trip out a code. Hell, we used to do it when my Dad had his POS '81 Olds. Delta 88 when we thought the alt. was shot. 
08-14-2003, 09:10 AM
#30
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nicky if u have a radar detector or anything else that can measure the cars voltage make sure its not falling below 10.5volts. I use my escort 8500 to monitor that. I also have a 1.0 cap, jl 500.1 amp and a 10w7 which draws ALOT of power. my installer told me the cap only ensures that the amp gets the power it needs. so kinda like pulling it and then storing so u don't get spikes/lows. but if your batter and alternator isn't sending the power fast enough then all your lights/electrical stuff might dim down, esp when your not on the gas. They've recommned to me to get the top of the line stinger battery which is alot of amps, forgot about the specs but I think cardomain sells them.
08-14-2003, 10:14 AM
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Or an Optima battery....NOVA...let me know what you do. The only lights that dim are my dash lights....especially the gear indicator lights.....everything esle stay nice and bright.
08-14-2003, 02:29 PM
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Oh your problem is different. Mine was specifically and only the tranmission gear indicator light squares on the tach on the dash changing shades of brightness.
And it went away since the trans was replaced.
And it went away since the trans was replaced.
08-15-2003, 09:10 AM
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Use a multimeter, put the test leads on the appropriate battery terminals, you should have the alternator pumping in 12.6 volts DC or a little higher. Try this test with your accessories on, lights and a/c, this will show if your alternator can perform under load.
However, the voltage may drop below 12.6 volts DC with a powerful stereo system turned on and up, so try the rpevious test with the stereo off or at a low volume.
However, the voltage may drop below 12.6 volts DC with a powerful stereo system turned on and up, so try the rpevious test with the stereo off or at a low volume.
08-16-2003, 12:06 PM
#37
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Originally posted by Chemmech
Use a multimeter, put the test leads on the appropriate battery terminals, you should have the alternator pumping in 12.6 volts DC or a little higher. Try this test with your accessories on, lights and a/c, this will show if your alternator can perform under load.
However, the voltage may drop below 12.6 volts DC with a powerful stereo system turned on and up, so try the rpevious test with the stereo off or at a low volume.
Use a multimeter, put the test leads on the appropriate battery terminals, you should have the alternator pumping in 12.6 volts DC or a little higher. Try this test with your accessories on, lights and a/c, this will show if your alternator can perform under load.
However, the voltage may drop below 12.6 volts DC with a powerful stereo system turned on and up, so try the rpevious test with the stereo off or at a low volume.
And a multimeter will not tell you if your alternator is going, it will only tell you if you votlage regulator is working correctly.
You need to do a AMP test to really check your alternator. You alternator could be producing 13-14 volts, but not enough amps. A voltmeter will not tell you that.
08-16-2003, 11:15 PM
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your wrong siggy. I have had my car running and disconnected the battery and it continued to run fine with no code... It didn't run as buttery smooth as with a battery hooked up because the battery acts as a buffer for the whole electrical system including the ignitions coils.
I spent 2 1/2 years working for a company that made batteries and we would also test electrical systems when installing batteries. Your alternator should be putting out 13-14 volts. If your voltage regulator is bad the voltage will be really high(like 16-17 volts)
90 % of the time voltage is a pretty good indication of the health of the alternator.
So if your worried about the alternator just disconnect the negative wire on the battery using a 10 mm wrench or socket. (it is normal for your car to run a little rougher though but should still continue to run)
I spent 2 1/2 years working for a company that made batteries and we would also test electrical systems when installing batteries. Your alternator should be putting out 13-14 volts. If your voltage regulator is bad the voltage will be really high(like 16-17 volts)
90 % of the time voltage is a pretty good indication of the health of the alternator.
So if your worried about the alternator just disconnect the negative wire on the battery using a 10 mm wrench or socket. (it is normal for your car to run a little rougher though but should still continue to run)
08-17-2003, 10:33 AM
#39
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Originally posted by AK_MOBBER
your wrong siggy. I have had my car running and disconnected the battery and it continued to run fine with no code... It didn't run as buttery smooth as with a battery hooked up because the battery acts as a buffer for the whole electrical system including the ignitions coils.
I spent 2 1/2 years working for a company that made batteries and we would also test electrical systems when installing batteries. Your alternator should be putting out 13-14 volts. If your voltage regulator is bad the voltage will be really high(like 16-17 volts)
90 % of the time voltage is a pretty good indication of the health of the alternator.
So if your worried about the alternator just disconnect the negative wire on the battery using a 10 mm wrench or socket. (it is normal for your car to run a little rougher though but should still continue to run)
your wrong siggy. I have had my car running and disconnected the battery and it continued to run fine with no code... It didn't run as buttery smooth as with a battery hooked up because the battery acts as a buffer for the whole electrical system including the ignitions coils.
I spent 2 1/2 years working for a company that made batteries and we would also test electrical systems when installing batteries. Your alternator should be putting out 13-14 volts. If your voltage regulator is bad the voltage will be really high(like 16-17 volts)
90 % of the time voltage is a pretty good indication of the health of the alternator.
So if your worried about the alternator just disconnect the negative wire on the battery using a 10 mm wrench or socket. (it is normal for your car to run a little rougher though but should still continue to run)
I *never* said it would throw a code. Why don't you read my posts before stating things which I *didn't* say.
I also said 13-14 volts was normal for a alternator.
You battery acts as a capacitor to clean the electrical systems noise too amongst taking any extra load/starting the car. Which is why your car was running rough when you removed the battery. Because your electrical system is out of balance
If your A/C decided to turn on and off while your battery was disconnected your system, you for sure would have seen a voltage spike. Soon as you disconnected the battery you created a voltage spike. Any major spike could potentially fry your ECU or any other electronics. I've seen it happen.
I suppose you connected an oscillo scope and watched the signal to verify the noise on the line? And got a true voltage reading.
I agree a lot of the times voltage is a sign of the alternator going bad. But you can have fine voltage and the alternator not being able to produce enough amps. Since really the voltage regulator can be fine, and the coils/contacts in the alternator are dirty/going bad.
So the fact I worked as a mechanic and was ASE certified means nothing eh? takes a bit of studying/work
Your logic is kinda like playing russian roulette. You pointed the gun and your head, and you got lucky. So based on that logic everyone else should be ok doing it...
What did you do for the battery company? install batterys?
Working for a tire company installing tires doesn't mean you understand how tires are made or engineered.
Sorry, bottom line is the best test for a alternator is a machine which simulates loads to the alternator. Removing the battery while the car is running doesn't prove your alternator is working 100% correctly. And it DOES put your cars electrical system at risk. Showing your alternator is putting out 13-14 volts shows it has enough to charge the battery. Not neccessarily keep up with load of A/C fan,stereo, ECU, or coils at high RPMs.
So ummm what exactly did I say was wrong? A voltmeter will ONLY show you the voltage regulator is working correctly. Thats all you can determine for sure with it.
Are you a EE or EET?
b.t.w.
The reason the car would throw a code is because of all of the noise introduced in the electrical system when you disconnect the battery. It throws everything off. The ECU would get misreadings and assume something is wrong. But I'm sure you knew that...
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