Major alternator problems on 91 gp se

[StewartFan20]

Ok, the 91 gp se I have keeps blowing out alternators with no rhyme or reason that I have found yet. Over the past year and a half this problem has drove me absolutely crazy. For example, 1st one went bad on a short trip to atlanta, replaced it, lasted about 3 days and went bad. Next one lasted several months and suddenly went bad. replaced it and time I started the car, it went bad. Changed that one and same exact thing happened with the next 2!! Finally the following one lasted a year and two weeks with no problems till a few days ago it went out. Now, I install another one and it lasted 24 hours and went out. Changed it out with another and time I started the car, it went bad. Put another one on and it lasted 2 days and it went bad when I cranked up the car to move it to cut grass. I have already replaced the battery with a new one, checked the positive wire from the battery to starter and up to alternator and it looks fine. I have also made sure that I charged the battery before every changeout. I am out of ideas and am in dire need of help here. Anyone care to take a stab at it? BTW, the alternator is from advance auto parts and its a palladium P79393, which has a lifetime replacement.(thank God for that!) I dont want to throw anyone off from an idea but it seems to me that they all make a slight "pop" sound right as the car is started when they go bad.

[richtazz]

You need to inspect the wiring running to the alternator. It sounds like you have a wire touching metal somewhere and dead shorting, killing the alternator. You need to inspect all positve wires under the hood, including the wire off the back of the alternator that goes back to the battery, the positive battery cable, both from the battery to the starter, and the branch to the "charge post" near the left strut tower. The randomness of time period is what makes me think it's a bare wire touching somewhere. A few times, while replacing the alternator, you've been lucky and while moving wires around, you've moved the offending wire away from it's grounding point. Eventually, it finds its way back due to road bumps and vibration and kills the alternator.

[StewartFan20]

Ok, I came home this afternoon with a better attitude about working on this thing and this is how it went....I started at the alternator, took it and the power steering pump loose, traced that wire all the way to the starter and found no problem. While at the starter I happened to notice that the silver stranded wire from the solenoid to the starter has been repaired by someone crimping on a round connector. About one third of the wire was trimmed off so it would fit in the connector I assume but it was cut short enough not to cause a short. From there I re-checked everything for tightness on the starter with everything ok there. Now I remove the air cleaner box and checked that wire all the way to the battery and didnt find any problems with it. After being frustrated not finding anything wrong with the wires I checked the connection you mentioned by the battery where the fuel pump relay is and it was loose enough to remove with my fingers. As I looked at it closer I noticed it had small burned pits in it which I guess could have been caused by the loose connection? Anyway, I smoothed it back down and shined it up with a file and put it back on tight. From there I found a loose ground from the battery to the chassis right above the top radiator hose so I shined it up and put it back on. I ran out of time so I only checked the motor ground connections to be sure they were tight and they were fine. After putting it all back together and cranking it up, I was happy to notice that first of all the alternator was working and charging at 14.3 volts and that I no longer have a problem with a slight dimming of the headlights, blower motor stays strong even when I hit the brakes.(Before today, anytime I would apply the brakes the volt meter on the dash would drop below 13 volts if I had the blower on high and you could hear the motor slow down slightly) I dont know if any of those loose connections could have caused the alternator to blow or not but so far everything seems to be much better. I guess time will tell. Thanks for the reply richtazz, youve helped me more than once here on the forum and its much appreciated. Do you think any of those loose connections could have been causing all this?

[richtazz]

Absolutely, the loose connections were causing voltage fluctuations and were most likely frying your alternator. Electricity seeks it's own path of least resistance, so when a fitting is loose (especially the main terminal you found) it can backfeed through and cause a surge or short, resulting in a fried alternator or burnt circuit. It sounds like your issue is resolved, and it was my pleasure helping you out. Thanks for the positive feedback, we like happy endings here on AF.

[StewartFan20]

richtazz, I hate to burst a happy bubble but it didnt fix it. Wife jumped in it this morning and the second time she cranked it up.....it fried it. Im not real familiar with the circuitry on cars so this may sound like an odd question but here goes. Is there anything else on this particular circuit other than the starter that could cause this? After my wife called I was wondering if there could have been a wire I missed or overlooked that may feed over to the under hood fuse box or something. If not, maybe its a flakey starter from time to time...Im really at a loss here. Im gonna hunt down the book on this car and see if it has a wiring diagram in it for the starting system. I mean, if I understand car wiring correctly, If it was a circuit shorting out AFTER a fuse it would be blowing that fuse instead of frying the alternator right? I will leave it at that until I hear back from you and go search for that book. Its around here somewhere. We will eventually figure this thing out. ;-)

[StewartFan20]

ok, I just finished up tracing the wiring from the under hood fuse panel and that wire also checks out ok. When I was taking the fuse panel off and I turned it over, a small blue fuse dang near fell out of its spot, very loose. It was a 15 amp and was labled ignition. I took a tiny flat blade screwdriver and closed up the connection better so it fits tight like it should. Dont know if that could cause a spike on the alternator or not but I fixed it anyways. Im heading back out to begin removing the starter and try the one off of a 92 lumina I have in the back yard that I grab parts off of.

[StewartFan20]

Well, I got the spare starter off in case you think it might be the culprit. A huge rainstorm came our way so Im gonna wait till tomorrow after work to get back at it. richtazz or anyone else who might have an idea what to try next, I'm all for it. In the mean time Im gonna go and see if anything comes to mind.

[richtazz]

You may have to pull the relay center under the hood loose and turn it over. Inspect all the wires for corrosion where they come up through the bottom. You may also need to inspect the junction where the underhood harness connects to the interior harness at the firewall. Do you have an aftermarket stereo, amp, etc... in the car?

[StewartFan20]

ok, I did look uner the fuse panel and that was good but I havent checked going thru the firewall but I will shortly, and nothing aftermarket is in the car, its totally stock. If the rain lets up I will post back and tell what I found.

[StewartFan20]

ok, finally quit raining and I went back at it. I found what I believe you were referring to with the large harness that goes in thru the firewall on the passenger side. It appears that maybe the belt had broken at one time and had broken the cover off of it. It was dirty and I cleaned it with compressed air and it looked good visually after I did that. Is there a way to remove it/unplug it to verify that water hasnt made its way in and caused a bad connection. I could see a large torxix screw down inside of it...is that how its removed or is it worth messing with? Im seriously beginning to wonder if it isnt just sorry rebuilt alternators. I did go ahead and put on another one this evening, drove the car for quite a while, had everything electric running, started the car several times and it never failed.....Im just at a loss.....lol......maybe it just doesnt like my wife driving it anymore

[richtazz]

I used to work for Advance, and their alternators/starters are decent. With as many as you've gone through, I say the problem is a short somewhere in your car. On the wiring harness, there should be a bolt in the center of the junction, and removing that bolt separates the halves. One more thing I forgot to mention. Check the wiring harness to the ECM. The ECM is mounted under the hood, beneath the plastic cover that the overflow bottle mounts to in the right front fender area. They are notorious for corroding, and the ECM controls alternator output.

[StewartFan20]

Ok, I will check both of those today when I get a chance. It seems to start raining here the last few days right as I get off work. Post back later with what I find.

[StewartFan20]

Well I was only able to check the computer between the rain showers and the connections were all good. I also wrote down the number just to be sure I dont have one of those faulty ones. It was a brown color, and I could only make out that it was remanufactured and the numbers were 7-7727. I already have the computer out of the lumina and it is silver and the numbers on it are 01227727 if it does ends up needing to be changed.

[StewartFan20]

I have some different news on it today. My wife was driving around town and she said the needle on the battery gauge was bouncing up and down eratically for a few minutes and also the oil pressure gauge will only read 70 no matter what the RPM's are. Dont know that its related to the problem but I wanted to mention it just in case it might lead to something. So far so good on the last alternator install. Other than the wacky gauge thing today, its working fine.

[Mickey#1]

It sounds like you've gone through almost 10 alternators. At what point was the battery changed?
Any chance your fan belt is slipping?

If the alternators are always going when starting then I think your idea of changing the starter is a good one.

Here's a long shot. Could a bad motor mount be letting the engine move & tug on any wires. Hey, I said it was a long shot.