Aright,
Recently I purchased a one owner 1987 T2 with 68000 miles for $1500(not so perfect compression... i think around 6-7 on the mazda compression test... Beautiful Body tho!!!). I was driving down the highway one night and I noticed lights go dim, radio cutout... etc. I get it to where I'm going and hang out for a bit. Nervous, I stick the key in the ignition and tadah! Car starts again, get to where I'm going again and hang out. Try to leave... car starts... gets me a mile down the road and blah.... dead. Obviously the Alt. Right? so turns out the previous owner had the same problem and purchased an alternator from autozone... dun dun dun. Autozone is ****. I know that. Apparently he didn't. Anywho, get the alt replaced and then the alt belt snaps. Dry rotted. Get the car towed home, that was 4 days ago. Last night I replaced all the belts. Car needed a jump. Easy? No. Apparently not. Step dad crosses the terminals and fry's the main 80A fuse. I Go get a new one. Replace it. Jump the car (without crossing the terminals) and the car runs for about 15min. Then dies. Extremely Dim door lights. I checked all the fuses, checked the battery fluid level. Everything checks out. Rexy defeated me for the night and I decided to go ponder exactly what the hell had happend.

Couldn't figure it out. So i came here. and searched. and searched. and searched. Didn't find anything.

So... Bad alt? Obviously the battery isnt getting a charge. Also the car will not remain running. So bad alternator, duh. But what made it die so soon? Autozone said this was the twelfth one. What gives? Bad ground? I know these cars have inherent grounding issues. When the car was running, I noticed a strange hesitation that is not constant at around 5k rpm's... Issues linked? I Made sure the battery terminals were connected properly. Checked all the alternator connections. Don't know where else to look or what else to do. HELP!!!!

 

My alternator was bad in mine, it probably had something to do with my amp drawing to much power. It murdered my alternator and caused my battery to die the day I got it. I ended up getting a 70amp alternator from CarQuest and it has worked ever since, charging at 14 volts. The only thing was the pully was too deep and was eating through my belts. We had to replace the alternator belt 3 times or so. We put a smaller pully on it and it's doing fine. So I suggest an alternator from a better place than Autozone. I hope it's not your wiring or something grounding out or bad ground. That would be a pain to try to find and fix.

 

I know the alt. is dead. The bigger question is why has it gone through twelve? isnt it kind of weird, even for an autozone part, to go through so many without getting a decent one?

 

ok.. this it out of my book.. (were covering this in class right now)
u will need a voltmeter.
for proper operation of any charging system, you gotta have good elec connections between
1)positive terminal on the battery to the alternator output terminal
2)the alternator must be prooperly grounded

whenever there is a suspected charging system problem simply follow steps to measure voltage drop of the power side charging circuit

step1) start engine and run at a fast idle (about 2000 rpm)
step 2) turn headlights on to ensure an electrical load on the charging system
step 3) using a voltmeter, connect the positive test lead to the output terminal of the alternator. then the negative ttest lead to the positive post of the battery.

if there is a 0.4 volt reading or less, then wiring and connections are ok.

if voltmeter reads higher than 0.4 volts there is an excessive voltage drop between the alternator output and the positive batt post.

if voltmeter reads battery voltage, or close to battery voltage, there is an open circuit betwen the battery and alternator output.

you can also check the ground side by connectig the positive terminal of the voltmeter to the negative batt post and the negative terminal of the voltmeter to any part of the alternator frame. the maximun volt reading for this is 0.3 volts

 

em... what if the car doesnt run? if i jump it... itll die right after i remove the jumper cables... i think...

 

It sounds like you may have a short. I'd charge the battery up with the neg post disconnected. After charging, touch the neg cable to the neg post, and see if you get a big spark, if not; turn the ignition on, and try it again. If you get a big spark; start looking for a short. Make sure all your fuses are the right size. If the previous owner was having problems, he may have up-sized a fuse on a problem circuit. I can't understand going through alternators like that. An Autozone alternator is good for a couple years anyway, and they do have a good warranty.

 

Took the batt. and alt. out. took them to autozone, both tested good. Charged the batt and then installed everything again. Everything seems to be working.... Ran until i shut it off. and promptly started back up again. Friggin weird. Could it be that the battery(being near dead, 1.5 volts output) was creating to much of a drain on the alt causing the car to shutdown? I dunno, i did all the continuity checks and everything was good. still tryin to figure this out... would hate to get stuck on the way somewhere i HAD to be... any ideas?

Also, ive noticed that the only warning lights that come on when the key is turned to on is the e brake light and the door light, if i have the door open and the ebrake engaged... what gives? what lights are supposed to come on?

 

You may want to check the bulbs in your alarm panel to start with. If it's running and your showing good voltage on your charge guage, your probably OK. I would make sure all the fuses are the right size.

 

well, drove the car for the past few days. nothing to fishy. thats a lie.

All was well until i forgot to pick something up... was supposed to pick up some sugar on the way home. I had forgotten until i got home. so i turn back around and head back to the car. put the key in and try to turn over. flooded. *****! put the peddle to the floor, which usually works, still flooded. pull the egi fuse, turn it over for about five seconds, stop, repeat twice. put the fuse back in, try to turn it over again. Still flooded, only this time when i turn it to on, ALL the warning lights come on. I've certainly got an electrical demon somewhere in this car. Hunt begins tomorrow. The warning lights are controlled by the cpu arent they? under the drivers side of the dash???

 

all the warning lights should be on if the key is in On or Crank and the engine is not running.

If there are not on during Crank and On with the engine not running, that is a issue.

If the idiot lights are on while the engine is running, then you have a bad alt or bad CPU or disconnected alt.

 

They do not *normaly* come on if the key is turned to the "on" position". I think this may have something to do with why the heck it's been through so many alternators...
Thankfully they have not come on while the engine was running. But, the last time the alt. went out, i dont recall them coming on at any point either.
Why'd i have to fall in love with such a needy car? I'm seeing a pattern in my life... beautiful cars... beautiful women...

 

The reason your car was dying is because your battery was too dead. An alternator needs some battery power in order to create the field in order to charge If your battery is stone dead, you boost it and take the cables off right away, it will die most of the time. When you put a new alternator on you NEED to have a decently charged battery, and you need to make sure your battery is good. With the car idling, with lights and **** on, make sure the alternator is putting out more than 12 volts, less than 15. Charge should go up slightly as you rev it.

In case you don't know how to check how much the alternator is putting out, take your volt meter, and put one probe on the pos. terminal and one probe on the negative terminal on DC volts.

Can't remember with my FC, but in almost all cars, with the key on ignition off, the dummy lights should all light up. They will slowly go out one or more at a time. When the car is running properly (AKA electrical system is charging properly) they should all be out. My old N/A had some issues with the ignition though, sometimes I had to fiddle with the key while it was running to get my wipers to work and stuff..

 

They should.
Perhaps then you have not installed the alternators correctly. Is this the correct alternator for series car, or are you trying to use a later model or higher output alt and it is not wired correctly???

 

Where should i start looking for the culprit?
Nope, correct alternator for series car. Being bone-stock has its benefits... no need for more amperage.

 

Lesson: don't replace alternator without first taking the battery to be tested and fully charged.

I actually fried a brand new 100 amp alternator because I hooked it up to my battery that was now toast.

 

Lol it seems i learned that lesson. I just hope thats all it was. ya know? Just have to track down the culprit for the warning lights... Checked all fuse sizes, all check out. Any pointers?

 

Took the warning light cluster out, resoldered the cold solder joints... what else could i be having an issue with? Been searching... cant find anything as to why the warning lights arent coming on... With the exception of people having bad connections with the alt. Made sure everything was hooked up and checked out. twice. What now?!

 

The idiot lights are turned on by the CPU on a S4 car, that gets its signal from the Alternator.

So at the CPU, do you have voltage (12+ volts) on the Black/Yellow and White/black when the engine is running and ground on the White/black when the engine is off?

If yes, then if you ground the Yellow/blue at the CPU with the key on, does it turn on the idiot lights??

 

I didn't read previous posts so flame me if i missed it..but the easiest way to fry an alternator, is a bad battery..Check battery voltage, should be ABOVE 12.6...below this is no good. And once the car is jumped expect a surface charge of 14 even 15 volts if alternator is working..also you can jump the car and watch the battery voltage on a DVOM, you should see the batt voltage raising somewhat steadily..



edit: I just read previous posts hehe..if your battery was down around 1.5 volts the thing is completely Sulfated, get a new battery..end of story.. I recommend an optima gel cell, best battery for the money..

hope that helped..

Dave.

 

I will be checkin that tonight!

Battery has not been actin funny, took a charge, has been taking a charge. If i have electrical issues again, the battery will be the first thing i check. thanks for the tip!

 

well being that we are talking about a wiring problem and icemark is sharing his input on the problem at hand-i have a similar and even worse issue...

first- i had an alternator grounding out problem-changed out the lead wiring (the ones going under the oil filter 8-)..) in hopes to solve a chemicaly exposed wire. everything was grand under one rainy afternoon... battery died taken some chick home. so from there i get a continuity(spl) tester and have at it, my 10A door/trunk light fuse was always grounded at and strong. tested my s4 tII it would come on a bit then fades out. then on my s5 gxl tested and the tester comes on then fades out. also if i try to turn my light on next to the rear view mirror, the clock goes out!
sacond. tested other circuits to find my headlights are grounding out at the main fuse box, but only when there on. so unless its dark or bad weather thats no causing it.

third-never get a key chime-never get a key illum, engine code spitted out a fuel relay, changed that out and still spits out fuel relay, tryed changing out the main fuse today, but that resulted in a no start-so i guess my replacement was bad...

but as the car is now i can drive it for 3 or 4 days, then when the volts start dropped i charge the batt.

this is on a 145k miles 89 vert. after reading on this post i have a few qs.

could this be the CPU or ECU? also do i have to replace with a vert specific CPU/ECU or with the 91 gxls work. thanks yall

 

My clock goes out sometimes when I turn my headlights on. Not that it works right anyways...


Just ohm out your fuse. If it maxes out, it's broken. If the Main Fuse was shot, not much on your car would work (relating to the car running). Your headlights still would.

 

CPU or ECU doesn't controll the idiot lights in a S5, and your issues would be entrily unrelated to the problem this thread was started with. The ECU controls the engine, and of course would be un-related all together.

In fact your issue sounds like a blown room fuse.

 

Yes, there is around 13-14 volts on the black/yellow white/black when the engine is running.
no, there is no ground on the white/black when the engine is off. nor does grounding the yellow/blue turn on the idiot lights.... whats all that mean?! im scared...

 

bad or dsconnected idoit light cluster