Cougar Posted March 29, 2012 Share Posted March 29, 2012 You're welcome for the help Heartless. Yes, the output lead of the alternator is the heavy gauge wire that ties to the stud bolt with the nut. It has to handle a lot of current so a large wire is needed along with a solid connection point. Using the procedure I mentioned above the meter is set to measure DC voltage. There are a lot of good easy to read books available that cover how to work on and learn about electrical systems for the automobile. They will show you how electricity works, how to use test equipment, and make tests on various things. It is well worth the small cost of a book. There are a lot of things on the internet you can refer to also. Quote Link to comment Share on other sites More sharing options...
Mikevan10 Posted March 29, 2012 Share Posted March 29, 2012 I just reread this thread since it is quite informative for me. I am paying the price for having avoided really learning about electrical circuits for most of my life. Question 1: In his first post on this thread, Heartless said that the voltage was a “…hair shy of 14 volts at idle, no accessories on. Switch headlights on, and it bumps up just a tad, as expected.” Well, that is just the opposite of what I would have expected. I am assuming that the voltmeter is, for all intents and purposes, measuring the voltage across the terminals on the battery, and I would expect that voltage to DROP slightly when a load (i.e. the headlights) was placed on it. Question 2: In a later post, Heartless reported that “…apparently there is nothing wrong with the alternator - it was pushing out 15.5 volts at 2000 rpm, with hi-beam headlights on, and heater blower going full force. (guage only showed 13.5 volts)”. I do not understand how you get these two different voltages. Again, aren’t we really talking about the voltage (potential difference) across the battery terminals in all cases here? If so, how could the alternator be “pushing out” 15.5 volts but there is only 13.5 volts across the battery terminals. Sorry for being so dense about this stuff. Just trying to understand what is really going on. Thanks! Mike V. Quote Link to comment Share on other sites More sharing options...
Cougar Posted March 29, 2012 Share Posted March 29, 2012 (edited) The voltage regulator range can vary some with different loads on it. As long as it stays within a certain range (13.2v to 14.8v) things should be ok. It sounds like there may be a little issue with the alternator since the voltage went over 15 volts. That is a little too high. The difference in the voltage readings is mainly due to where they are taken from and a little bit due to using different meters. The meter in the dash takes the reading from wiring in the dash area. There are voltage drops due to wire and connection losses between the battery and the dash wires. This can be as much as a volt. The more the current load in the wires the greater the voltage drop with be. The dash meter is also just a cheap meter and isn't nearly as accurate as a DVM will be. It is accurate enough to give you a close reading though. Edited March 29, 2012 by Cougar Quote Link to comment Share on other sites More sharing options...
heartless Posted March 29, 2012 Author Share Posted March 29, 2012 the max voltage that the alternator will put out (for this unit anyway) is around 15.5 volts - so, that particular day, at that particular point in time, it was pushing out the maximum. anyway - back to the issue at hand... cleaned all the ground connections that i could find. Other half used the car to take the dog to the vet and reported no problems for the trip (about 15 miles each way) driving to school this evening, the dash light dance started up again - all the warning lights came on, voltmeter dropped to just under 12, then just as suddenly, everything went out & meter returned to 13+ this little light show happened several times in my 18 mile drive. about ready to pull my hair out! what am I missing? (and just for the record - heartless = female ) Quote Link to comment Share on other sites More sharing options...
heartless Posted March 30, 2012 Author Share Posted March 30, 2012 same light show on the way home - on and off, on and off... does not appear to be any rhyme or reason to when they come on, or go off (don't have the light hooked up on the gauge, so cant see that after dark). sometimes just a brief flicker, other times on for a minute or more. does not seem to be tied to bumps in the road (of which there are plenty) grounds that have been cleaned: *Main negative battery cable ground to trans bell housing bracket (both bolts) *smaller cable off main to front chassis *there is also a smaller gauge wire (12 ga?) running from the neg battery cable clamp to the chassis below the battery box - possibly an add on by a PO? *ground between dog-bone bracket & firewall anyone have any other ground locations? I feel like I am missing something, somewhere, but danged if I know where. Quote Link to comment Share on other sites More sharing options...
Cougar Posted March 30, 2012 Share Posted March 30, 2012 (edited) The warning lights are tied to the alternator lamp circuit so they can be tested when you turn the ignition switch to ON without the engine running. When the alternator is working it supplies a backfeed voltage on the lead and the lights turn off until there is a problem with the alternator. From your previous statements about the alternator it sounds like there is an intermittent problem with it. I think if you replace the alternator you will clear these troubles. Edited March 30, 2012 by Cougar Quote Link to comment Share on other sites More sharing options...
heartless Posted March 30, 2012 Author Share Posted March 30, 2012 The warning lights are tied to the alternator lamp circuit so they can be tested when you turn the ignition switch to ON without the engine running. When the alternator is working it supplies a backfeed voltage on the lead and the lights turn off until there is a problem with the alternator. From your previous statements about the alternator it sounds like there is an intermittent problem with it. I think if you replace the alternator you will clear these troubles. Yeah, that is what I thought too, but (big But here) I have no money to buy a new one, and in order to get it replaced under warranty, it has to "test" bad with the parts store's equipment....so basically, I am screwed. I do have an old stock unit I can swap in to test the theory, but I dont know as I trust it to last for very long. Quote Link to comment Share on other sites More sharing options...
heartless Posted April 2, 2012 Author Share Posted April 2, 2012 Well, went saturday to get the alt tested once more - still getting the light show periodically. Again I was told that the alt tests fine. The person that did the testing this time claims to be a former "master tech" - and we had a rather interesting conversation. He asked if the car was a slavage, had ever been under water/gotten wet - answer: no, clean title and to my knowledge it had not. he asked a few other questions - and then I remembered - the first winter I had this car it got completely packed full of snow under the hood (see my avatar?), and some had even managed to get inside, past the door seals...oops... :-\ ok, so sunday I dig into the dash area that had gotten snow in it - behind the lower dash panel where the little "tray" is - which happens to be very close to where the fuse box is located. I was very careful about drying everything out back when this happened, but ya never really know, it is possible that i missed something, so I went with that assumption. I went so far as to completely pull the fuse panel out to make sure there wasnt corrosion anywhere - did not find any corrosion under the dash, but I did find that the greater majority of the connectors had a lot of very fine dust/dirt in them. So everything got cleaned up, blown out, and reassembled - only some driving time will tell if this has done any good, or if the problem continues to persist... Now - anyone know where the big "super junction" referred to in the FSM is located??? Or is that something that would require pulling the entire dash out to get to? (not sure I want to go there) Quote Link to comment Share on other sites More sharing options...
Fairtax4me Posted April 2, 2012 Share Posted April 2, 2012 There's a huge one under the dash where the wire harness comes through the firewall. It's way over in the corner over top of the drivers kick panel I think. Did you happen to check inside the plug on the alternator for corrosion/dirt/crud? Quote Link to comment Share on other sites More sharing options...
heartless Posted April 3, 2012 Author Share Posted April 3, 2012 There's a huge one under the dash where the wire harness comes through the firewall. It's way over in the corner over top of the drivers kick panel I think. hmmm...looking under the hood, on my car, there is a harness that goes thru the firewall on the passenger side of the tranny..."diagrams" (line drawings) do show this, and also show that wiring as spreading out under the dash to various components other "diagrams" in the FSM do indicate that the SJ is on the drivers side, more than likely up behind the guage cluster, but i dont see where any wiring goes into the passenger compartment on that side of the engine bay as the diagram "suggests"? Would this be the large loom that goes into the fender area, and disappears from sight? and would it be possible to access by pulling the guage cluster out? Did you happen to check inside the plug on the alternator for corrosion/dirt/crud? Yup - all clean there, the main feed wire is also clean. doing the check as described by Cougar Another good check to make in case you think there is a charging problem is to check the voltage drop between the alternator output and the positive battery post while a good load is on the system. You should hopefully see less than .3 volts across the connection due to standard wire losses. showed a very tiny reading of only 0.03 volts - I am assuming that this is very good, and that the alt is, in fact, fine. (meter set at 20 VDC) Also, when checking ground points at various locations with the car running, i see 0.02 volts, or less, difference between reading at the actual battery terminals and reading at the ground points I know the car is a 22 yr old rust bucket, but it is all I have and I cant afford to have to replace the darn thing. being jobless for more than 2 yrs really sucks the big one. Quote Link to comment Share on other sites More sharing options...
Cougar Posted April 3, 2012 Share Posted April 3, 2012 doing the check as described by Cougar showed a very tiny reading of only 0.03 volts - I am assuming that this is very good, and that the alt is, in fact, fine. (meter set at 20 VDC) Also, when checking ground points at various locations with the car running, i see 0.02 volts, or less, difference between reading at the actual battery terminals and reading at the ground points Your testing shows the external wire connections are good but that has nothing to do with the internal operation of the alternator. I believe it is bad. If you have a spare one I suggest you put it in the car to try and confirm it. Quote Link to comment Share on other sites More sharing options...
heartless Posted April 4, 2012 Author Share Posted April 4, 2012 i am carrying a spare & tools with me just in case. Took it for a short drive this evening, so far so good, but didnt really go long enough to know for sure. will know more tomorrow night after driving to town Quote Link to comment Share on other sites More sharing options...
hankosolder2 Posted April 5, 2012 Share Posted April 5, 2012 I had a similar problem with a Honda some years ago; parts store guy claimed that alternators "are never intermittent." Being an electronics technician, I was quite confident that I had checked the wiring thoroughly, so I deliberately fried the alternator to ensure it would test bad. "Gosh, it seems like it's quit entirely now, could you test it again, please?" Installed the new alternator and the car worked fine for close to a decade after that. The problem with taking measurements with an intermittent problem is that the measurements are only relevant WHEN the issue is occurring. I would suggest that you install your spare alternator for a test or try a junkyard alternator if money is tight. Hope that helps. Quote Link to comment Share on other sites More sharing options...
heartless Posted April 5, 2012 Author Share Posted April 5, 2012 yeah, i was told the same thing - alternator problems aren't "intermittent" - horsepuckey! anyway - the drive yesterday/last night went well, no light shows at all. I even pushed it a little the last 8-10 miles home using the high-beams and the heater - still no light shows - not even a flicker. I am cautiously optimistic about the issue being resolved - the thing is, it has been cooler the last few days than it was when the problem started, so I am going to hold off on the "fixed" dancing banana thing until it warms back up again to see if there are any changes. if the problem does rear its nasty head again, I will swap in my spare to test the theory for a week or so. I don't do a whole lot of long distance driving - most of my driving is 30 miles or less one way so even if it does puke completely, I should be able to make it home at least. My only real "fear" is that the darn thing will crap out after dark when I will need to use headlights at the very least (which is why the spare remains in the car, with tools to swap it out, and a flashlight just in case!) Quote Link to comment Share on other sites More sharing options...
heartless Posted April 17, 2012 Author Share Posted April 17, 2012 Well damn - the light show is back. After all the cleanup, and cleanout a few weeks ago, everything had been fine for a while. But this evening i drove to school, was in class about 1.5 hours, left school went to get gas, then started for home - about a mile from home the dash lit up just like before. And I am fairly certain now it is not weather related - was down right chilly today, even had snow flurries - was warm when all this started. Will be swapping in a different alternator tomorrow - hoping this proves (to me) the current alt is bad....if it does (and I will give it time) the next step will be "proving it bad to the parts store... Quote Link to comment Share on other sites More sharing options...
heartless Posted April 18, 2012 Author Share Posted April 18, 2012 Changed out the suspect alt with one from a parts car - an original stock unit no less - not pretty to look at, but it seems to be working - maybe. initial start @ idle I get a DMM reading of 14.02 +/- volts at the battery (13.5-ish on the guage inside the car - roughly a half volt difference) drove to school - in class for 2.5 hours, then drove home last night with no light shows. also noticed my crazy, fluctuating idle once warm seems to have gone away as well - a might early to say for sure on that one yet, but... While driving it "reads" fine - staying right around 13-13.5, depending on the load (lights on, radio on, etc) but at warm idle, the guage is only showing around 11 - 11.5 volts - going with the half volt reading difference from cold idle, that would be 11.5 - 12 volts at the battery? that just seems a bit low to me... guess I should double check it when warm with the DMM at the battery to see just what it is doing. Quote Link to comment Share on other sites More sharing options...
Cougar Posted April 18, 2012 Share Posted April 18, 2012 The voltage readings seem pretty normal to me though maybe slightly on the low end. It would be nice to know what the battery voltage is while the engine is running around 1,500 RPM while the lights and blower are on full. Quote Link to comment Share on other sites More sharing options...
heartless Posted April 18, 2012 Author Share Posted April 18, 2012 (edited) well, when the other half gets home (and if it isnt pouring down rain), I can get those readings for you Cougar - kind of hard to do by one's self, however! LOL Found a local rebuilder of alternators and starters with a good reputation - gave them a call, explained the problem to the guy, and he at least has given me confirmation that yes, it could be failing intermittently (which the parts store says they dont do - yeah right) - but without actually seeing it, testing it, and possibly cracking it open, they cant really tell me much. Edited April 18, 2012 by heartless Quote Link to comment Share on other sites More sharing options...
heartless Posted April 19, 2012 Author Share Posted April 19, 2012 Ok Cougar - here are some numbers for you...these were taken after everything was warmed up good No Accessories: Low Idle (700-750rpm) - 12.02 volts High Idle (1750-1900rpm) - 13.42 Accessories on - High beams, heater blower on high, stereo (same idle ranges as above) Low Idle: 11.8 High Idle: 13.2 + it seems that the old stock alt is functioning reasonably well as long as the rpms are above a certain point - other half was on the meter at the battery, said as soon as I started to bring the rpms up, the meter started going up as well. But thru all of that, not once did I see the dash light show that I was getting with the rebuilt unit - not even when it was reading under 12 volts! Also, the erratic, surging warm idle really does seem to have gone away - have not had that happen at all since swapping in the old stock unit. I do have at least one other stock alt here that I can try out to see if it works any better - which I may do this weekend, just for grins & giggles. I took the suspect alt in to the local rebuild shop to have them give it a look over, should have more info tomorrow morning on that. I may just say screw it all with the "lifetime warranty" unit and have the local shop rebuild one of the old stockers - cost would be about the same as buying yet another piece of junk one if I cant get the one replaced... and these guys do stand behind thier work. They dont advertise at all, and have almost more business than they can keep up with. Its either that, or go the upgrade route mentioned earlier...but I would need both the alt, and the pigtail to plug it in for that one... Quote Link to comment Share on other sites More sharing options...
Cougar Posted April 19, 2012 Share Posted April 19, 2012 Well I think it is safe to say the other unit is bad and hopefully the store will exchange it for another one. You have proven it is bad. The one now in the car might have some damaged diodes since the output voltage is a little on the low side. I would like to see between 14 and 14.8 volts at high idle. At least it is working well enough to get you by. As far as having the shop rebuild one you should watch the costs of doing that. Sometimes it can be more than buying a remanufactured unit. Quote Link to comment Share on other sites More sharing options...
heartless Posted April 20, 2012 Author Share Posted April 20, 2012 yeah, I am aware of the potential cost differences - have already looked into it. The problem is, Advance wont replace the one under warranty unless it "tests" bad on their equipment - since it is a heat related failure at this point, it probably wont "test" bad, until it completely fails - and I can not afford to have it completely fail and ruin a good battery along with it. To purchase a replacement remanufactured alt it would cost me $120 - less the $34 core charge - net cost of $86. The Beck-Arnley unit is over $200... to have the local shop rebuild would run between $70 to $100 on average - about a horse a piece when you get right down to it. Sure, I get the "lifetime" warranty on the reman unit from Advance - BUT - getting a replacement is turning into a huge hassle anymore. I have had quite a few of these "lifetime" alternators go bad after only a year or so - same "brand" was used on the old GL, and I had to replace it just about every year. the current one with issues is about 1 yr old (this month) Getting pretty sick of it. Quote Link to comment Share on other sites More sharing options...
heartless Posted April 26, 2012 Author Share Posted April 26, 2012 ok, swapped in the second of the two used alternators we have, this one seems to be charging better at lower rpms - have not actually put the DMM on it to verify, but the guage is reading better... BUT The irratic warm idle is back - not as bad as before, not as often, but it does get a weird every now and again... can't seem to win for losing... anyway, at this point I am convinced that the first alt is bad, even if it wont test so at the parts store. going to see about having one of the old stockers rebuilt - If I have to spend money yet again, it wont be on another inferior, mass produced unit. Quote Link to comment Share on other sites More sharing options...
eulogious Posted April 26, 2012 Share Posted April 26, 2012 http://www.ultimatesubaru.org/forum/showthread.php?t=129024 My write up on the EJ alt swap. I would just order the '97 alt from the dealer. It was going to cost me about $100 to rebuild the stock alt locally from a good alt rebuild shop, and only $78 for the newer EJ alt from the dealer. Just go with the dealer alt if you are trying to save money. Other reason I would go with the newer alt is that if it fails again, you have an alt that is off of a newer car and you might have better luck finding something that will work with newer gen parts. Quote Link to comment Share on other sites More sharing options...
heartless Posted April 27, 2012 Author Share Posted April 27, 2012 http://www.ultimatesubaru.org/forum/showthread.php?t=129024 My write up on the EJ alt swap. I would just order the '97 alt from the dealer. It was going to cost me about $100 to rebuild the stock alt locally from a good alt rebuild shop, and only $78 for the newer EJ alt from the dealer. Just go with the dealer alt if you are trying to save money. Other reason I would go with the newer alt is that if it fails again, you have an alt that is off of a newer car and you might have better luck finding something that will work with newer gen parts. Interesting write up, and I may do this in the future, but the nearest dealer is over an hour away, and the shop that is rebuilding is only 20 mins - they also have an excellent reputation for doing quality work. just because - alternator I am running right now is out of the other half's old car - which has over 260,000 miles and I "think" it is an original stock unit. The alt i took to the shop today for rebuilding I also believe to be a stock original unit, but came out of a 162,000 mile car. Quote Link to comment Share on other sites More sharing options...
bosango Posted May 1, 2012 Share Posted May 1, 2012 This thread has reminded me to remind myself to update my original post on the bizarre charging problems I was having. Maybe my fix might work for you. I believe I went through three replacement alternators and two or three replacement batteries before the problem was solved. I had also checked every connection and possible problem source a million times. You can do a search and read the story, but the short version is the charging light kept coming back on and the battery wasn't charging. The replacement alternators and batteries proved only to be temporary fixes. On the advice of one of the forum members who also had mysterious charging problems, I replaced the starter with a rebuilt one. That was about 10,000 miles ago and I haven't had a problem since. The only indication that the starter might have been bad was very rarely, maybe one start out of 50, there would be a short split-second delay from the time the key was turned to the time the starter turned over. I have since talked with someone who seems to have also fixed his charging problems with a new starter. Go figure! Hopefully someone here can explain the reason behind this. Quote Link to comment Share on other sites More sharing options...
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