Ok, let me see if I can explain: Your car is not wired properly and you are therefore having very unpredictable trouble with your starting-charging system. Does that pretty much sum it up for you? You can choose to whine and do nothing or you can attempt to fix it.

The 'S' terminal controls the voltage ouput. I like to think of the 'S' stands for sensing since it senses the voltage at the remote site (fuse box) and adjusts the output to maintain 14.4 volts. In an absolute pinch, it could be hooked up to your 'B' terminal, but you will not maintain the 14.4 volts, more like 12.8v to 13.2v. This would be functioning like a one wire alternator.

The 'L' terminal is a little more fuzzy in my mind. Some people go along without it with no trouble, some have minor voltage variances. You do need it, but could get by without it.

To recap, you must have the 'B' terminal and the 'S' terminal.

You should have the 'L' terminal.

Like it or not.

Done.

 

jackhild59 is right that the S is the sensing line. What that means for you is that if your car is running, the alternator needs to know that it's supposed to be putting out voltage. It does this by "watching" the S terminal through a diode. If you don't have this hooked up to a power source, then (in my understanding), the alternator will only put out power when it's a high load condition such as higher RPM.. That's basically "Shocking" your alternator to life as it's sitting there, not getting any signal saying that the electrical system is getting weak then all of a sudden gets hit with a high load condition and jumps to life.

The L terminal is mostly used to display your voltage to the ECU/gauge cluster. I don't know that the Rx-7s do anything with this information (other than display it as a gauge).

There's a more detailed description, now go and hook up your alternator properly so that way people don't have to keep beating you over the head with it!

As indicated by the picture posted by jackhild59, the S/L connector for the S4s has a black/white wire and a white/black wire.

/not hailers, but I want to be when I grow up!

 

i 100% appreciate your help..thank you very much. i wasnt whining i was just wondering why it would run for so long without that connector..thats all.

 

******************The L terminal is mostly used to display your voltage to the ECU/gauge cluster. I don't know that the Rx-7s do anything with this information (other than display it as a gauge).
************************************************** ***************
It has Nothing to do with the voltage gauge .

The L wire initially feeds the Field of the alternator voltage and also is used to alert the driver, thru the warning lights, that the alternator is working or not working.

Thats why in the ENGINE ELECTRICAL section of the FSM, they have a trouble shooting procedure where you have the key ON, engine OFF, and with all electrical plugs on the alternator, check the L wire for a reading of 1-3vddc. It's to assure you that there is voltage there to excite the Field in the rotor when you start the engine. After it gets running, the field is fed from the diode trio and the field regulated from...the regulator in the alternator.

The voltage gauge gets it's reading/power thru the Meter fuse. The meter fuse gets it's power from the ignition key/switch. The ignition switch gets its power from the engine bay fuse box when the alternator isn't putting out and directly from the alternators B terminal when the alternator is charging.

 

The only explanation I have, is that the rotor in the alternator has residual magnatism and that is what gets the alternator excited enough to put out. Once it *puts out* the three diode assy feeds the Field and the thing keeps on a running. But with no S wire it can't be regulated voltage imho.

If you have a na with a volt gauge, don't completley rely on that for a reading. Go to the B terminal on the alternator itself to see what the real/total output is.

 

ok..i can see how the wires are supposed to go but i dont really know where to start when it comes to doin this... where do i get the wire..is there a certain way that is optimal to wire it

edit:

i can see that the b-terminal goes directly to the battery..as well as the s- terminal. my b is already hooked up so i just have to wire the s to the battery and the L to the dash. how do you wire the L to the dash

 

DoH! I was close...

HAILERS - Check your PMs!

 

another question...so what plug did i have goin into the alternator..it fit perfect and had one yellow and one white wire

 

what about the fact that where the alternator bolts up is painted ...does that affect the grounding in anyway

edit:

i also just realized that the plug that i had in the back of the alternator(yellow and white wire) made the warning lights come on when i turned the key..if this was the wrong plug why did that happen

 

You probably have the right plug on if it fit perfectly. Your colors don't seem to match the FSM wiring that is online. I guess their faded or ?????? W/L is white with a blue stripe. W/B is white with a black stripe.

So if the plug fits and the warning lights come on when the key is put to ON/engine OFF, that's the way it works

The guts of the alernator ground thru its case mating to the engine. So the spot where the alternator attach bolts meet the brackets should be bare or free of paint. I mean where the alternator mates with the adjustment bracket and where long bolt on the bottom of the alternator meets the engine should be paint free. You can see if it's making good contact by putting the meter on ohms and one meter lead on the case and the other meter lead on some part of the engine. Reading should be less than .3 ohms or so. Preferably zero or .1ohm.

Seems in this thread you had no plug on the alternator..............then later in the thread found the plug and attached it. Now you turn the key ON and the warning lights work right.

Measure the output by putting your positive lead on the B terminal and the meters negative lead on the case of the alternator (some bare metal spot). At idle it should be over 14vdc.

Then while your still there, and I know this might sound odd but do it, leave the meters Positive lead on the B post and put the negative lead on the Batterys Positive post. IF you read over a half volt then you have a bad connection b/t the battery B post and the main fuse box/battery. Meter on dcvolts when you do the above.

Tell you what, if that last part makes no sense, go here: http://www.aa1car.com/library/charging_checks.htm

and go down that page to where it says VOLTAGE DROP TEST and read that and do that.

Sorry, I never ever read PM's. UNLESS you can tell me where the money is that I lost in the years 1999 and 2000 (Dot Com BUST) and where the money is that I lost somewhere around Sept 2008 (the NINJA LOAN BUST). I've looked under the couch and in the backyard and under the car seat. Can't seem to find out where it got lost.

NINJA meaning No Income-No Job- No Assets required for a housing loan from the banks, resulting the bums not being able to make a simple five percent housing loan payment. I wish them ILL.

 

well theres no other plugs anywhere in the engine bay that are the same?? i have the A/C removed so i assumed it could of had something to do with that

 

I doubt its some other plug. I have a series four car with series five alternator. The series four elect plug is on a short breakout of the harness. I looked at the series five ENGINE ELECTRICAL pages and notice the series five alternator plug is on a faily long breakout of the harness and seems to be biased to the left side of the car. I'll attach a jpg of what I mean....

The two jpgs show the two different locations of the plug on NON TURBO and TURBO engines, and if you follow the wire on the plug, it seems to be pretty long in the two jpgs attached.

Last time I looked, the a/c compressor uses a lone wire with bullet connector.

 

ok this makes me think i have the right plug..soo i just reinstalled the alternator with the plug in. with 2 clicks of the key all of the warning lights come on now. unfortutley i have a dead battery so i cant start it to see what happens.. at this point would it be a bad a idea to jump the car? i have one of this little jump starter packs u charge in the wall

 

MD0101 - Sorry to threadjack

Hailers - It wasn't about free money in your PM, but about free beer! I'm in town until friday was offering to buy you a beer (or beverage of your choosing) for some help a few years ago Give me a call if you want to meet up tomorrow or something 570-974-1786.

 

Thank you, but no. I've got Pink Eye right now.