Is my alternator going bad?
02-02-2013, 08:43 PM
#1
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Is my alternator going bad?
I bought my Civic about 3 weeks ago and thus far it has served me faithfully, even after I pushed it to the limit on a back road. However, I feel like the alternator may be starting to die. I noticed tonight as I was driving around that my car would idle very low and pull itself back up, almost as if it wanted to die. My lights and accessories work, but when I crank the heater from OFF to 4 right away the revs drop (normal) and the lights dim. There is also a rev drop when I turn the steering wheel while stationary (normal). But the weird idling tonight had me legitimately concerned. After looking under the hood I noticed it is the original alternator, and the car is about to pass 140 K on the clock. PROBLEM: anyone who has a D16Z6 will know that the alternator is not ideally placed in the engine bay. It is deep in the engine. I wish it was where the power steering pump was, but it's not. I'm not sure how I will change it, even after changing my friend's alternator on his 88 escort (alternator was on top, right in plain view). Probably gonna take it to a shop and have them deal with it. Any ideas though? What could be causing this unsteady idle? And what are signs of a bad alternator WHILE DRIVING OR IDLING, not using instruments?
02-02-2013, 08:51 PM
#2
Seagull Management
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Re: Is my alternator going bad?
Get a multimeter and see if it's putting out 14.2V at idle. Seriously, this whole trying to diagnose a bad alternator without actually doing any basic tests on it is just plain stupid.
If they use road salt where you are you may have a very miserable job changing that alternator, and you make not have a core to take back either. If you live in a place with no salt it's actually a pretty easy job.
If they use road salt where you are you may have a very miserable job changing that alternator, and you make not have a core to take back either. If you live in a place with no salt it's actually a pretty easy job.
02-03-2013, 07:05 AM
#4
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Re: Is my alternator going bad?
What do you mean about the whole salt/no-salt stuff? I live in Illinois, where it snows a lot, so yes, we have road salt. I know salt can screw with electrical systems, but how does this matter? The alternator is inside the engine and I doubt will be touched by any salt. And even so, why would that make a difference in changing it? 
02-03-2013, 07:09 AM
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Re: Is my alternator going bad?
What do you mean about the whole salt/no-salt stuff? I live in Illinois, where it snows a lot, so yes, we have road salt. I know salt can screw with electrical systems, but how does this matter? The alternator is inside the engine and I doubt will be touched by any salt. And even so, why would that make a difference in changing it?
The through bolt that as the name implies goes through the bottom of the alternator gets seized in the aluminum alternator body. Sometimes you have to smash the alternator around the bolt and take it out in pieces to remove it. Sometimes you'll break the cast iron lower bracket as well.
02-03-2013, 07:20 AM
#6
Re: Is my alternator going bad?
^ exactly
Happened to me, Iowa uses salt like nobody's buisness. That through bolt got stuck in the alt and it was an absolute ***** to get out. Good luck.
Happened to me, Iowa uses salt like nobody's buisness. That through bolt got stuck in the alt and it was an absolute ***** to get out. Good luck.
02-03-2013, 09:06 AM
#7
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Re: Is my alternator going bad?
It's not inside the engine, it's behind it.
The through bolt that as the name implies goes through the bottom of the alternator gets seized in the aluminum alternator body. Sometimes you have to smash the alternator around the bolt and take it out in pieces to remove it. Sometimes you'll break the cast iron lower bracket as well.
The through bolt that as the name implies goes through the bottom of the alternator gets seized in the aluminum alternator body. Sometimes you have to smash the alternator around the bolt and take it out in pieces to remove it. Sometimes you'll break the cast iron lower bracket as well.
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02-03-2013, 09:52 AM
#8
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Re: Is my alternator going bad?
If it is idling weird and almost stalling, I would pull and clean the idle air control valve (IACV) aka EACV. Also clean the throttle body in place (follow the directions on the carb cleaner), especially if it feels sticky when you move it by hand.
Check the "Sticky: FAQs - Frequently Asked (Tech) Questions" for a how-to on cleaning the IACV.
As far as the alternator, what was said above, test with a multimeter while it is running. You can get really cheap multimeters if you don't have one.
EDIT: Some major chain auto parts stores will do this test for free.
Check the "Sticky: FAQs - Frequently Asked (Tech) Questions" for a how-to on cleaning the IACV.
As far as the alternator, what was said above, test with a multimeter while it is running. You can get really cheap multimeters if you don't have one.
EDIT: Some major chain auto parts stores will do this test for free.
02-03-2013, 11:09 AM
#9
B*a*n*n*e*d
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Re: Is my alternator going bad?
My boys at AutoZone tested my alternator and the news is in: everything is fine. So I am going to do what dazebreak said, which is cleaning the Idle Air Control Valve. It's funny, because I also suspected the IACV was dirty because sometimes when I start the car when it is still a little warm the idle will fluctuate from 1500 to 1000 revs for about 7 or 8 seconds before dropping back to normal 800 rev idle. I think the ol' IACV is due for cleaning.
MODERATORS: please close this thread.
MODERATORS: please close this thread.
03-09-2014, 06:51 PM
#10
B*a*n*n*e*d
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Re: Is my alternator going bad?
***UPDATE***
I hate bumping old threads, but this one was mine and I am having similar issues again.
Replaced the alternator belt a couple weeks ago, everything ran great after i adjusted the belt tension. Still the same old *** alternator. I also have a dashboard mounted voltmeter. Most of the time I get readings around 13.9 to 14.4 while driving. Idling with some accessories on gets me 14.2 or 14.1. All accessories at 14.0.
Recently it has warmed up.
Drove earlier today, all normal.
Went to take my girlfriend home 20 minutes ago (night time) and I noticed when I stepped on the brakes the headlights flickered hard core then came back up, and the stereo cut out. Voltage readings went crazy. When I got to her place I was idling, and it kept jumping around from 13.3 to 14.6 volts nonstop, occasionally settling at 14.4. At one point I stepped on the brakes and the volts went to 11.7 before jumping back up. It wasn't doing this a few hours ago, and I haven't touched the car. i'm gonna let it sit overnight and see how she is in the morning.
I checked under the hood. Belt is tight and rotating. quickly opening the throttle a lot will slightly increase the brightness of the headlights at idle. I made sure the battery cable to the alternator was firmly planted.
Please help.
03-09-2014, 06:59 PM
#11
Re: Is my alternator going bad?
A year later. Probably no longer related to your original post, which is why necro'ing posts is a bad idea.
Do this.
"Repair procedure" is "Replace alternator".
Do this.
Diagnosis
1. Test the battery (see page 23-77 of the 1996-1998 Civic Service Manual). To accurately test the voltage regulator, the battery must be in good condition and fully charged, with any surface charge removed.
2. Warm up the engine to normal operating temperature, then connect a voltmeter to the positive and negative terminals on the battery.
3. Read the charging voltage after running the engine at 2,000 rpm for 5 to 10 minutes with all electrical loads OFF
^ If the reading is less than 13.5 V or more than 15.1 V, go to REPAIR PROCEDURE.
^ If the reading is between 13.5 V and 15.1 V, go to step 4.
4. Turn off the ignition switch, and connect the voltmeter to the battery positive terminal and the alternator B terminal.
5. Start the engine, then read the voltage drop with the engine at 2,000 rpm and all electrical loads ON.
^ If the reading is less than 0.4 V, the charging system is working OK at this time. Return the vehicle to the customer.
^ If the reading is more than 0.4 V, tighten the nut on the alternator B terminal and the bolt attaching the white wire to the under-hood fuse/relay box. Go to step 6.
6. Repeat the voltage drop test.
^ If the reading is less than 0.4 V, the charging system is working OK at this time. Return the vehicle to the customer.
^ If the reading is still more than 0.4 V, go to REPAIR PROCEDURE.
1. Test the battery (see page 23-77 of the 1996-1998 Civic Service Manual). To accurately test the voltage regulator, the battery must be in good condition and fully charged, with any surface charge removed.
2. Warm up the engine to normal operating temperature, then connect a voltmeter to the positive and negative terminals on the battery.
3. Read the charging voltage after running the engine at 2,000 rpm for 5 to 10 minutes with all electrical loads OFF
^ If the reading is less than 13.5 V or more than 15.1 V, go to REPAIR PROCEDURE.
^ If the reading is between 13.5 V and 15.1 V, go to step 4.
4. Turn off the ignition switch, and connect the voltmeter to the battery positive terminal and the alternator B terminal.
5. Start the engine, then read the voltage drop with the engine at 2,000 rpm and all electrical loads ON.
^ If the reading is less than 0.4 V, the charging system is working OK at this time. Return the vehicle to the customer.
^ If the reading is more than 0.4 V, tighten the nut on the alternator B terminal and the bolt attaching the white wire to the under-hood fuse/relay box. Go to step 6.
6. Repeat the voltage drop test.
^ If the reading is less than 0.4 V, the charging system is working OK at this time. Return the vehicle to the customer.
^ If the reading is still more than 0.4 V, go to REPAIR PROCEDURE.
03-09-2014, 08:54 PM
#12
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