Alright... before the flaming begins, I just want to point out that I have done the search and have looked at maybe 20 or 30 threads on here talking about charging system issues. I've tried to find this information as opposed to posting a question. The closest thing I found did indeed give me a schematic, but not the one I need.

Anyway, I have an '87 305 with the TPI. I've been having charging system issues. Wires from battery to starter and alternator are good. Grounds are good. I don't know about the wires on the alt's weather pack... which is why I need a schematic.
So, what have I done so far? When I first noticed the problem, I got the car running and checked alt output with my 6 LED quick check device. It siad I was getting battery voltage. Pulled the alt and took it to Advanced Auto to get tested... output on their machine was like 9V. Yep... fried. Replaced the bugger. Put new alt on... still have the same problem. Checked the fan fuse... good.
At one point I bypassed everything between the battery and alt by running a single 4awg wire from the battery to the alt... same issues took place.
Finally, I disconnected the battery cable from the alt completely, and started the car. Checked the output at the battery terminal of the alt to ground... nothing.
1) Does anyone have any idea what could be wrong?
2) Does anyone have a copy of the schematic for an '87 305 TPI? Please note, the weather pack has 3 wires: red, brown, and brown/white.

 

I'm having the same issue. I checked wire from starter to alt, and wire from battery to alt. All checked out good. Took the alt to autozone to get it tested. tested good. I too would like the pinout for the rectifier plug. where does the brown and the brown/white wire go to?

 

Ok... no responses?

How about this... anyone have any clue which wire on the weather pack energizes the stator field?

Whose idea was it to not use a friggin permanant magnet for the stator field anyway?!?

 

I know there is someone who can help us out. What do the brown and the brown/white wires go to?

 

This is from the Tech Articles on TGO for an '86

http://92b4crs.tripod.com/86wiring/dia-pics/30-10.jpg

I don't think the '87 would be that much different (but I've been wrong before). Hope it helps some.

That link isn't working. Go to the homepage thirdgen.org and the tech articles section under electrical.

 

Ok... I used the link above and one I found by Yahooing "LB9 Charging system schematic" and I've determined this: the brown and brown/white wires are, electrically, the same internal to the alternator's case. Outside, the brown wire runs to the volt meter in the dash and the brown/white wire runs to the ignition switch.

I just took my voltage tester (it's really a cheap unit... 6 LEDs with circuitry to make them light up at different voltages, from 5V up to 15V). I checked the battery as it sits... I got more than 5V but less than 10V based on the 5V LED fully on and the 10V LED trying to come on (I expected this... the battery is run down from having the car running on it). Checked the red lead on the weather pack, to ground, expecting the same response... got it. Checked the other wires, with the key in run, with the same expectation... both bad.

My next course of action is to run a wire from battery to the weather pack pin for the brown/white wire to see if straight output from the battery will power the stator field. If this works, I'll figure a way to run a line from an ignition slot on the fuse box to the same spot on the alt. I'll keep you all posted.

 

ok my connector is broken so i need to know which wire goes to which pin.

 

Ok... I actually just clipped the brown/white wire and capped the loose end. The end coming from the weather pack, I spliced with a wire running straight to the battery... still nothing from the alt.

Makes no sense!

More work will ensue.
This is getting pretty rough... I moved from Hawaii to Maine in August. I'm not used to working on my car in 25 degree temperatures... or in total darkness at 6PM!

 

First....Is yer test E.Q. workin right?Second with the mods ya have you have done (unsure what procedures your using)would you have to change your test procedures?Third question....Have you checked the batt?I have had bad (dead cell)batts screw up alt testing in the vehicle,and kill an alt in the wifes 01 blazer.
I do seem to recall running across multiple diagrams for alts.Will check files and see what can find.Also are you useing the old style hookup like in my 79 olds?1 wire runnin to batt/2 or 3 wire plug in connector?If so then this link might help.
http://www.acs.ucalgary.ca/~csimpson/Tech/RConvert.html
I used it to install the internaly regulated G.M. alt in my 70 ford F-100.If memory servs me the brn wire referanced in diag was running to grnd.I referanced my ford schematic for the brn wire off the pictured diagram.And the alt diag from the pic for the rest.Best of luck will check files see what i have....Bill

 

Also check this link.It's on highoutput but hookups and tech should be same just more output.
http://www.alternatorparts.com/cs130_sbpage1.htm
Again best of luck.Still lookin...Bill

 

Wire diag from autozone for car might help.
http://www.autozone.com/servlet/UiBr...3d801eef19.jsp

Assorted wire diags from 85 service manual someone refered me to forget whom.3rd gen is 3rd gen.
http://www.geocities.com/vtcamaro/Wire-Diagrams.html
Yet again best of luck this ole R d eck is gone to work......Bill
P.S.I miss Maine.Winters on Vinalhaven were a blast and ice fishin is awsome.Not to mention catchin a Musky in the summer is an adventure initself.Watch for the teeth.

 

Update on this...

Hadn't done anything for a while... Uncle Sam had me working 13 hours a day, every day, for the last 2 weeks. Today, I finally have a day off, so I used the time to fix this.

Before I left off, I had narrowed the problem to the brown/white wire I spoke of earlier (which goes to the middle pin on the weather-pak). Some continuity checks showed that the wire is broken somewhere between the ignition switch and wherever it taps off and goes to the fuse box. I ran a wire from an "IGN" tap in the fuse box out to under the hood. Took continuity across that and the brown/white wire where I snipped it earlier... good. Voltage check on the extra wire, key in "ON"... good. Voltage check on brown/white wire... bad.
So I ran the extra wire through a grommet in the firewall, routed it to the weather-pak, and charged the battery. Once all that was done... hit the ignition. Car fired. Checked voltage at battery... 15V! Works like a champ.
This'll stay in place until I swap the motor out for a 383.

 

Hi SpeedKnight,
I'm in the same boat, and before I try your idea, just wanted to know if it's still working?

After replacing the fuse panel and wiring all new wired up to it my alternator has not been working. I'm assuming I've left the field wire unconnected and this should fix my problems, but just wanted to see if yours is still going, or if the wire is keeping the alternator on and draining your battery?

 

on the stock alt, it requires a switched 12v source for the alt to work properly (as the OP found out his wasnt working and ran a new one). its not all that uncommon for something to happen to that switched 12v wire and thus the alt will stop charging. its usually the first thing i check on these cars when the alt stops working. since its a switched 12v source, it has no power when the key is off, so it shouldnt drain your battery or do any harm. it WILL drain your battery and greatly reduce the life of your alt if you hook that wire to a constant 12v source (like directly to the battery)

 

What about the deal with this resistor or diode? Is it necessary or can I get away with running a new wire on an ignition rail from the fuse box?

 

the diode just keeps voltage from backfeeding and keeping the ignition going after you shut the car off and the alt and/or electric fan is still spinning.

 

oh ok, so it doesn't need a specific signal or resistance to trigger the charge?

 

nope, just the switched 12v source and the connection to the battery

 

Fantastic,
I'll try it today and see how I go, thanks for the help!

I was wondering why the diagrams showed the tan/white wire going to the voltage gauge, but then still showed voltage while the plug was off the alternator, and that was screwing me up.

 

New annoying symptom.... I haven't done anything to car yet, went to go get lunch from up the road and when i started the car....14.9V on the gauge!!!
I hate cars!
Still not sure if it's a short/loose wire, or the alternator itself bugging out.