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-   -   Problem holding a charge, belt dust around alternator (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/problem-holding-charge-belt-dust-around-alternator-982907/)

19rxseven87 01-08-12 04:21 AM

Problem holding a charge, belt dust around alternator
 
Hi guys,

The problem is that my alternator won't charge above 13.8 ish at idle and 13.7 ish at throttle. There is belt dust that forms around the alternator, the alternator was replaced multiple times finally back to a used OE one. Ones from autozone were POS and wouldn't even charge past 13 volts.

I'm confused at what this problem is. I can charge the car overnight with a battery charger, run the car for half a day then I start needing light jumps to get the car started in the evening after a while. I had the alternator off of the car before I put it in and it tested fine at autozone.

Can anyone help with this? I've tried searching but not quite sure what to check for. I'm not sure whether or not it's the alternator again (though it tested fine at autuzone), the battery is good (newish one, tested good), a problem with the fan clutch, a problem with the water pump (it does heat up pretty hot during the summer, probably 3/4 up). I've had all of the grounds re-grounded, and the battery terminals replaced. Starter is newish as well.

Thanksin advance for input.

dwb87 01-08-12 04:45 AM

Seems like the alternator is fine.

Check for a drain... Remove the negative battery terminal, set a multimeter to AMP current (mA), one prong to the negative car terminal, one prong to the negative battery terminal, BE SURE ALL ELECTRICAL LOADS ARE OFF, now see if the multimeter is reading very very little current (mA) or zero... If it is displaying more than it should be, remove the 60A BTN fuse from the engine fuse box (so that you can open the door of the car without the lights coming on), go into the car and start pulling fuses from the fuse panel by your feet, one at a time. If that fuse doesn't get the multimeter to display zero, then put it back in and try another fuse. You can also try pulling other things... The way I found my drain, was by unplugging my turbo timer. The multimeter then displayed zero, and that's how I knew that was the problem.

dwb87 01-08-12 05:57 AM

Is there any damage to the belt? (Cracks, grease, etc...) - Is the alternator belt properly tensioned?? The pulleys do match up... Right?

19rxseven87 01-08-12 12:15 PM


Originally Posted by dwb87 (Post 10927535)
Seems like the alternator is fine.

Check for a drain... Remove the negative battery terminal, set a multimeter to AMP current (mA), one prong to the negative car terminal, one prong to the negative battery terminal, BE SURE ALL ELECTRICAL LOADS ARE OFF, now see if the multimeter is reading very very little current (mA) or zero... If it is displaying more than it should be, remove the 60A BTN fuse from the engine fuse box (so that you can open the door of the car without the lights coming on), go into the car and start pulling fuses from the fuse panel by your feet, one at a time. If that fuse doesn't get the multimeter to display zero, then put it back in and try another fuse. You can also try pulling other things... The way I found my drain, was by unplugging my turbo timer. The multimeter then displayed zero, and that's how I knew that was the problem.

will try this, thanks.


Originally Posted by dwb87 (Post 10927551)
Is there any damage to the belt? (Cracks, grease, etc...) - Is the alternator belt properly tensioned?? The pulleys do match up... Right?

no damage to the belt, no cracks, no grease etc, yes the belt is properly tensioned, albeit on the tighter side, pulleys do match up.

19rxseven87 01-08-12 02:12 PM

checked for a drain, no drain.

retensioned the belt.

also, checked the b+ terminal at the back of the alternator. it is putting out 14.00 to 14.1 volts at idle but it won't go up as rpm increases.

bad alternator, again perhaps? if so, i have had 4 bad alternators in a row? maybe just very bad luck?

satch 01-08-12 02:29 PM

You might have a problem w/the starting circuit that relates to the wiring or components not including the battery and alternator. When you need a jump, instead take a wire and run it from the positive battery terminal to the Black/White wire at the Starter Cut Relay (found on cars w/factory alarm and has only one plug to it) or the Black/White wire found in a Blue plug near the trailing coil. Doing this will bypass a number of connections as the B/W wire runs to the starter solenoid w/only one connection in between. When you use the jumper wire the starter ought to turn over immediately. See in the future if this makes any difference at all. If there is a stark/noticeable difference then you will be able to further narrow down your problem.

19rxseven87 01-08-12 02:36 PM

what gauge wire should i use? so instead of using an external jumper source such as a jump box, just take a wire from the positive terminal to the b/w wire near the trailing coil?

i've noticed that after the car is run for a while, when it doesn't want to start, it is pretty sluggish in turning over the car, but when the car is fully charged it turns the starter immediately.

19rxseven87 01-08-12 05:57 PM

also when car is warmed up, with the head lamps on, it is only charging at 13.3 volts. :( yuck. from the B terminal it is putting out 13.7ish volts but battery only charging at 13.3. should i bite the bullet for a higher output alternator?

bumpstart 01-08-12 06:12 PM

run an extra B+ wire from alt to the battery

if you have mix matched a s4 alt onto s5 car or vichy versa without appropriate changes to the field switching you WILL get battery issues

one way trickles all the time the engine is off,, the other overcharges and boils the battery

adding s5 alt to s4 car also requires the B+ upgraded as the B+ is marginal already for the amperage

19rxseven87 01-08-12 06:24 PM

should i fuse the additional b wire or just add it to see if it will help with the charging?? the alternator is an s4 alternator, not an s5 alternator. the car is an 87 rx7 tII (probably should've mentioned that)

satch 01-08-12 06:31 PM


Originally Posted by 19rxseven87 (Post 10928003)
what gauge wire should i use? so instead of using an external jumper source such as a jump box, just take a wire from the positive terminal to the b/w wire near the trailing coil?

i've noticed that after the car is run for a while, when it doesn't want to start, it is pretty sluggish in turning over the car, but when the car is fully charged it turns the starter immediately.

What was suggested was to "only" diagnose your problem. If you did what was suggested it will bypass some elements to check to see if there are issues besides the alternator/battery. This is just to check to see if the starter would turn over w/o any problem. One end of the jumper wire to the positive battery terminal and when the other end touches the B/W wire the starter should turn over as if you were starting the car.

19rxseven87 01-09-12 02:30 AM

noted, thanks.

any other suggestions? i've connected the b terminal at the back of the alternator directly to the positive battery terminal and it seems to be charging better *knock on wood*.

19rxseven87 01-15-12 01:07 AM

bump. i've noticed that when the car is cold the car seems to charge better than when it is already warmed up. any suggestions as to why this could be?

88_N/A_GXL 01-15-12 10:26 AM

It being cold and charging better is just because hot electronics lose efficiency.

manbeast 01-15-12 01:47 PM

is the belt dust from the alternator being tensioned too tight? my alternator belt has done the same thing. also not holding a charge.

19rxseven87 01-15-12 07:38 PM

no, the belt is not tensioned too tight, in fact it's maybe a little on the looser end. i can see it wobble up and down more so than my other belts.

is there any fix for this heat? because i've noticed that it gets so hot right now (in the winter time) and i don't think it'll charge well at all. i'm thinking this heat is from the creation of this belt dust.

dwb87 01-15-12 07:46 PM

Don't you have another thread asking about pulley alignment?

manbeast 01-15-12 09:49 PM

yea mine gets hot as hell as well. sounds like we are in the same here almost exactly. im going to go charge my battery tomorrow and trouble shoot ill post anything useful

manbeast 01-15-12 11:44 PM

i jumpstarted my car this evening and with a voltmeter it read 14.2 on the battery terminals and 14.4 for the alternator while it was running. and when off it was at 11.8 for both. isnt it supposed to be at 14.6 at the least while running and above 12.0 (not sure) while turned off? after i let it run for 10 minutes i tried to start it up again of course it didnt start it started to drain the battery i watched as the idiot lights got dimmer every time i tried to start it. it was sluggish and more sluggish after each attempt also it did click a couple times. not every time i turned the key just a few. the car starts just fine when the battery is fully charged. when i jumpstarted it tonight it didnt start up right away i had to let it sit for about 5 minutes so there definitely is a drain. does your car have the same symptoms? I searched threads on here and found some that go through this and one way to find the drain i thought sounded like a good way was to hook up a test light to the battery i think positive terminal and pull the main fuse (not sure) and if the light is turned on (do not turn key over) then you have a drain and to find it you need to start pulling fuses one at a time from the fuse box next to your feet or start dissconnecting wires one at time, also i read in an australian forum that the headlight flippy motors can be pulling power when car is off. anyways let you know tomorro

MIDNFauciUSN 01-16-12 12:24 AM

14.4 is normal while running. 11.8 is normal while off. 14.4 while running at least tells you that your alternator is pushing voltage to your battery. If your battery wont stay charged, but your alternator is sending electricity to the battery, suspect the battery. I say this under the assumption that there isn't an insane drain somewhere.

Finding out whether or not a current drain exists is not, in itself, exactly rocket science. Anyone with the most basic knowledge of a DMM can tell you that. Finding out what exactly is draining the current takes a little bit of time though.

manbeast 01-16-12 12:59 AM

does anyone happen to know the battery requirments for a n/a s4 rx7? i have a 650 cold crank amp battery not sure on all the other info. but it was the battery it came with when i bought it and i went and got a free replacement from walmart cuz it still had a warranty.

19rxseven87 01-16-12 01:19 AM

manbeast- yes, my car does exactly that. i don't think it's a drain because if the car is left sitting there, and started up cold, it charges perfectly. once it starts warming up the engine bay the charging starts to go downhill. there is belt dust buildup at the pulley and i am guessing that the friction caused by creating the belt dust is heating up the alternator much faster than radiant and convective heat created in the engine bay.

dwb87- yes i do have a question about pulley alignment, but after putting a straight edge to the pulley i dont think it is deviation side by side, rather up and down

dwb87 01-16-12 02:07 AM

I do NOT believe that you're getting so much heat from belt dust. Perhaps you should get that out of your mind. UNLESS your alternator is not properly aligned. Even then, it can't produce THAT much heat.

Concentrate on the alternator and the alternator wiring. Especially the wiring.

19rxseven87 01-16-12 02:48 AM

have tried 3 different alternators. I can take a picture of the alternator alignment or maybe even a video to show the alignment, but honestly the symptoms say that the alternator charges better cold than warm. i will try another alternator though..

dwb87 01-16-12 03:22 AM

Nah, you don't need to spend more money... My alternator did this a little bit. Not as bad. Seriously, checking the wiring. Do some extensive research with your multimeter.

19rxseven87 01-16-12 11:23 AM

the thing is, the alternator is connected straight to the positive terminal of the battery (i know this isn't particularly the safest thing to do but..) and all the grounds are good because i regrounded it with 8 gauge wire to the major grounding points.

manbeast 01-16-12 07:44 PM

So I jumpstarted my car this morning again i had to wait about 5 minutes to before i could start. drove about 3 miles to work turned off engine and put my volt meter reader to the battery post and it read 6.1 volts. last night it was 11.8 after i jumpstarted and turned off and checked with volt meter reader. sound like a drain or alternator not charging fully? i kind of am leaning towards drain since it was at 11.8 last night before i went to bed and 6.1 this morning after a drive to work. its losing power from something right? have refurbished 70amp alternator i checked the specs on my battery its actually 640 cold cranking amps its the maxx battery you get at walmart selection #5. Took my battery in today after driving there from work to get it fully charged and an hour later it came back a defective battery didnt have any cold cranking amps so i got a replacement off the shelf. this has happened twice now exact same battery type. cept for the first battery was paired with what seemed to be the stock alternator judging by the amount of rust it had, might have been newer but not much but i replaced it because i tested it at autozone said bad regulator regulator was 60 bucks and refurbished was 65 so i went with the refurbished since the old alternators fan blades were covered in rust and looked like it was grinding against the insides. also replaced belt. SO car now has new battery and I am going to put multimeter to it first thing in the morning and hopefully i find something out. I will do that test with the light as well. hope some of this info helps out further with the issue.

19rxseven87 01-17-12 06:05 PM

my high output alternator came in, installed it, and it is now charging at 15.3-6 volts at idle and 14.4 volts with maximum load (with literally everything on). is 15.3-6 too high for the car or will this be fine?

dwb87 01-17-12 08:26 PM

Should be fine.

What size belt are you using, though??

misterstyx69 01-17-12 10:42 PM


Originally Posted by 19rxseven87 (Post 10940953)
my high output alternator came in, installed it, and it is now charging at 15.3-6 volts at idle and 14.4 volts with maximum load (with literally everything on). is 15.3-6 too high for the car or will this be fine?

where did you get the HI output Alt?..How many amps does it put out?
and got any pics??

19rxseven87 01-18-12 12:28 AM


Originally Posted by dwb87 (Post 10941148)
Should be fine.

What size belt are you using, though??

I believe the belt size is stock?


Originally Posted by misterstyx69 (Post 10941326)
where did you get the HI output Alt?..How many amps does it put out?
and got any pics??

High output alternator from ace alternators on ebay. It looks exactly like the stock FC one.

manbeast 01-18-12 01:26 AM

legit I'm going to purchase one for sure. i tested new battery this morning at 1030 at 12.4 with everything off and let it sit until i got home at about ten tonight and tested it again at 12.4 with everything off so i guess no draw from anything thinking about replacing my new refurbished alternator with one of those high output after i get it tested to make sure its bad of course. i think it might have been a bad alternator to begin with. sweet deal baby jesus

19rxseven87 01-18-12 01:43 AM

forgot to mention it is advertised to have the capability to put out 130 amps.

manbeast 01-18-12 01:48 AM

for 165 bucks it better work right haha let us know if your battery explodes from the high output alternator or anything else weird happens.

RotaryEvolution 01-18-12 09:40 AM

the stock alternators when they get old and start failing usually charge just fine when the alternator is cold and then bleed off amps as the engine warms up, this doesn't really have anything to do with the wiring but the alternator itself.

i see tons of the stock alternators failing these days, they are just about at the end of their lifespan.

look up some of the many upgraded alternator writeups and don't bother with a reman stocker, they usually only last a few months at best.


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