npena80

SUMMARY: Seemed like i had a dead battery, but the alternator was bad. I replaced it w/ a new one, and drive 100 FT and the car wont start anymore. WTF? car WILL stay on, only if i connect another battery.

LONG VERSION: 88 NA GXL

I started my car and drove it around, and all was well. when i want to go out again, the coolant buzzer came on. So i turned the car off and filled my radiator. I try to start up again, but I have symptoms of a dead battery.

I get a jump start, and the car turn on w/ ease. pull the jumper cables and it wont idle. It runs if i keep my foot on the gas. i look at the voltage and it is at 14V or 15V if i have it connected to another car. while the car is off, it is at 0V - 8V w/o jumper cables. I pulled the cables after i got it started, and the voltage gauge danced around 12V. I decide to test alternator and it failed. so i replaced it w/ a new one.

I jump started the car and all seems well. I idle a couple of mins, rev to 3K a couple of times and it all stays on. I drive a couple of hundred feet and press the brake. car is DEAD! wont turn on. 0V on voltage gauge. I jump start again, but the car wont stay on w/o the cables.

pressing the brake pedal causes a BIG voltage drop on the volt gauge. I also thought i heard the sound of a motor activating when pressing the pedal. smaller drops occur when the hazards, turn signals, AC or wipers are turned on. My power steering is disconnected atm.

what are some possibilities? i want to know ANYTHING i can check for.

HAILERS2

Make sure the small, two wire plug on the back of the alternator is on the alternator.

Make sure the alternator belt isn't slipping.

The volt gauge in the instrument panel should read close to 14vdc if the car is idling. IF not, rev the engine to 1000 rpm and it should read 14vdc for sure.

If not, then pull the small plug off the alternator and make sure the Black/White wire reads batt voltage with the key ON, engine OFF. Should.

Then with the small plug attached to the alternator, put the key to ON, engine OFF and ***** the WHITE/BLACK wire with a sewing needle or such and see if that wire reads 1-3vdc with a volt meter. Should.

If the small plug on the alternator is left off for an extended period of time the alternator voltage regulator will destroy itself. Voltage regulators cost about 25 bucks.

Actually, a lot of your problem seems to be with the battery cable connections on the battery. They don't seem to be connected to the battery good or have heavy corrosion on the cable terminals or???? Just not making good contact with the battery posts.

Another possibility is that the small cable on the positive post of the battery (go look at the positive cable and you'll see it has one large and one small cable connected to the fitting) isn't making good contact with the fuse box in the engine bay. The smaller of the two cables on the positive cable goes to the middle of the engine bay fuse box. It's held on with a small 10mm socket size bolt, located under a plastic flap on the front of the engine bay fuse box.

IF you don't have a cheap Digital volt meter..........get one. This isn't rocket science. Just looking for dcvolts here and there. No I= E/ R stuff. Just reading figures on a meter.

'88 s5 t2

alright, i know you have a non-turbo car, but i had a very similar issue with my tII. so, how i got to diagnosing my issue was using a dvom(multi-meter) to test the resistance(no battery connected!!) between the alternator power anode(eyelet installed with a nut on dr side of alt) and the positive end of the vehicles harness that gets installed on the battery. there should be pretty much 0 resistance between the alt and the battery. if you have some resistance, try flexing the wire where it runs into the harness. on my tII that is where the wiring had been cooked and when wiggling the wiring, it would go from little resistance(4-5 ohms) to crazy high resistance(9 MEGA-ohm). if this is the case for you, just cut out the wiring where effected(will be discolored under casing) and splice in some monster cable or other quality wiring. hope this helps you out!

npena80

UPDATE:

the resolution to this problem was to replace my battery cables. as it turns out they were heavily corroded.

the lesson i learned is that we should all properly ground our electrical system.

rotarygod

iTrader: (1)

Bad wires is the cause of most electrical issues. Poor connections will kill batteries and alternators. If you know someone who has gone through multiple batteries or alternators in a fairly short amount of time, the issue is with their cables. As long as your wiring stays good, you will probably never kill the alternator in the life of the car and even the worst batteries will still last 4-5 years with good ones topping 7-8. Always check connections first. If something goes bad, there was a reason. Those cables are usually the reason.

npena80

cool insight...

thx