fd alternator problems...
 

Ok guys i have a 89 TII which has a supposed to be new fd alternator on it...Problem is when you first crank the car the alternator dosent put any voltage out untill you unplug the electrical connector and plug it back in. After you do that the alternator kicks in and charges good for a little while or untill you drive it a little then it stops charging again..You can keep repeating this procedure for awhile untill it gets to where that dosent even work anymore and you have to wait till the next day...What would cause this?? Voltage regulator maybe???

My battery is relocated to the rear storage bins and is done correct as ive went throu it to double check...optima yellow top battery that is about 4 years old...

thanx

How is the Alt wired.. Is the sense wire coming direct from the battery?

All the wiring for the alternator is stock I just tied my new positive cable into the old one under the hood and left all the other wiring alone

Just to make sure is the S terminal (closest to the B+ terminal) going to 12 volt constant while the L terminal goes to dash (W/B wire).

yes the s terminal has constant battery voltage...

One other thing I forgot to mention was do the idiot lights light up w/key to on but engine off and then turn off w/key to on but engine running? Since turbos don't have voltage gauges, correct me if I'm wrong, then how do you know when the alternator is putting out or not. If you wired up an aftermarket unit then are you measuring the voltage output at the alternator with a multimeter as well and comparing the two readings?

yes the gauges light up like there supposed too...im measuring the output with my fluke meter at the b terminal on the alternator...

Next time the alternator shows that it is not putting out try reving the engine and see if this changes things. If it does your alternator is damaged goods.

already tried that...has no effect...only thing that makes it put out again is by unplugging the electrical plug and plugging it back in....

You might want to focus on the plug itself as the contributor to the problem at hand.

hmmm dont really know what to look for...i took the alternator off and took it to a alternator shop and they said everything checked out fine....what are the symptoms of a bad voltage regulator???

Excessive voltage or just the opposite would be the symptoms. When you check the alternator and you see that it is not putting out check the S terminal to verify that it is still sending 12 volts on it. With respect to the plug make sure the two wires are firmly inserted into the back of the plug and not pulled back such that a faulty connection is occuring. Also, check the metal components inside the plug to make sure they are grabbing the alternator prongs firmly as opposed to barely hanging on.

ok thanx will check that tomorrow and report back

ok update...went and cranked the car today...and the alternator was putting out 16.5-17 volts right off the bat...i let the car run for about 5 minutes then it just randomly quit charging...i tried unplugging the electrical plug to make it charge again and this had no effect...and the s terminal did have battery voltage at the time when it wasnt charging...also when i first cranked the car and it was charging so much i unplugged the electrical plug and this made no difference it was almost 17 volts with the plug on or off....

The W/B wire should have 1 to 3 volts while plugged in and key to on but car not running. You'll have to back probe this wire for results. Also, this wire should have 12 volts on it while the car is running. If it does both then the problem is not the wiring but the alternator itself.

everything has the voltage that it should...so im thinking voltage regulator...does anyone know where i can buy a replacement one??

can anyone confirm that its prob the voltage regulator...and if so where can i buy one at??

its a ground issues i have the same problem as we speak for me it the grounds under the dash by the way does anyone know where is the ground locations under the dash

The alternator grounds to the engine.

other grounds .

With the car running and the multimeter set to DC volts place one meter terminal on the casing/housing of the alternator and the other meter terminal to the negative battery post (not clamp) and the reading should be about .2 volts or less. If it is then the grounding is fine. Poor connection(s) related to grounding causes resistance along the wiring which leads to voltage drops and not voltage increases. Also, placing a meter lead to the B+ terminal and the other lead to the positive battery post (not clamp) should read .2 volts as well. If not, then the wiring needs to be cleaned up.

There aren't any grounds under the dash related to the charging circuit except for the alternator warning light, which that particular grounds purpose is to only turn the warning lights on or off in certain instances but it does nothing else.

well u know that cpu( fb01)on the driver side kick panel,, i turn on the car and theres no alternation but when i move the plug the one on the front when u are looking at it , it kicks ,and then theres alternation

thats why i want to know the locations of ground under the dash for i can clean them , ive looked at the fsm already doesnt show wheres the ground under the dash

That would be the result of a cold solder/poor connection as opposed to a grounding problem. The ground wire in that largest plug grounds the alt. warning light which is not connected to the alternator and that ground wire also grounds the warning buzzer unit as well. It's labeled as grounding point #10.

iv been searching that too i wondering how do u take the apart?

i know i ve seen it done but i cant find anything

You would remove all plugs, remove the mounting bolts, remove the CPU and pop off the front cover to gain acces to the circuit board.

EDIT: http://www.johnr.com/rx7faq/faq3.html