Looking for Early S Man

[DEL]

Hello,

I'm a new Porsche owner. I bought a 1982 911 SC Targa last Friday. On Sunday it left me stranded with a dead battery. I'll try to make this brief as I can.

I've replaced the battery, and tested with a volt meter, confirmed that it was not charging. I then replaced the alternator and it sitll won't charge. I verified the battery light bulb on the dash is good (although it never comes on) while checking the bulb I somehow created a problem of a shorting (burning) brown wire that connects between the two left most gauge clusters! Keep in mind that (prior to the burnt brown wire problem) the car would start, run and drive just fine. All accessories worked great. I didn't even know I had a problem until the battery ran down and the car died.

I've read a lot of stuff on the web, and I have a Haynes manual here. I'm 36 and have owned many cars. I'm a descent mechanic but I'm totally new to Porsches. Any help would be great. I was told that Early S Man would be a good resource to contact.

Thank you!

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Dave Loney
1982 911 SC Targa
1986 Buick T-Type 10.43 @ 129

[Jack Olsen]

I'm no Warren, but here are two Pelican tech articles on the subject:

http://www.pelicanparts.com/techarticles/911_alt_replace/911_alt_replace.htm

http://www.pelicanparts.com/techarticles/mult_starter_diag/mult_starter_diag.htm



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Jack Olsen
My Rennlist home page • My Pelican Gallery page • My Porsche Owners Gallery page

[Early_S_Man]

Dave,

I hope you got the burnt ground wire (in Greman cars conforming to the DIN standard, ALL BROWN WIRES ARE GROUND) replaced and the short fixed!

The non-charging is related to your inoperative warning lamp, since pre-excitation current for the alternator field coils comes through that circuit ... open warning lamp circuit = no charging!

It is important to find out which type of alternator you have, and a very significant change was made during '82 model prioduction. The alternator was changed to an integral-regulator model, and several wiring changes were made at that time, and a service bulletin addresses some oversights that caused charging and electrical system problems for that model year. If you look on p. 310 and 314 of your Haynes manual, you will find the later version circuit for cars with the integral-regulator alternator, whereas the Pelican '82 diagram features the earlier version with separate regulator.

Here are the Pelican diagrams:





If your fan pulley shaft has a 17 mm diameter, it is the later-style alternator, otherwise it is the other style, and you should find a regulator on the panel with relays, and the CDI-unit on the left fender side of the engine compartment.

Did you happen to notice a ground strap from alternator case to engine block when you replaced the alternator?

The Blue wire from terminal D+/61 must have continuity from the regulator (if separate) or alternator to the dash instrument lamp holder, and you can test it with a multimeter ... if you have/make a set of test leads long enough! I made a set of 10-foot leads just for such testing.

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Warren Hall
1973 911S Targa

[DEL]

Warren,

Wow thanks for the information. There was no ground strap from the Alternator. There were only three connections on the back (one of them had two wires) so there are a total of 4 wires going to the Alternator. Is there a part number I can look for to locate the voltage regulator? There is a module on the left rear panel but I can't tell what its for.

So it sounds like I'll be tracing the wire from the battery light back to the alternator? Are there any factory connections there (or fuses/fusible links) that I should check first?

I have not replaced the burnt brown wire yet. I have no idea where the short is. The wires are all right there in front of you when you pull the gauges out. I couldn't see where the problem started from. I'm tempted to cut the burnt wire to avoid further burnt wires. It's really a drag because everything looked perfect in there before I started
I'll look further there tonight. Is there a chance that one of the gauges could have failed and caused this problem?

Thanks again for the info.

[DEL]

A couple more things I should ad.

When I tested the battery light bulb I also probed the two posts with my test light. I have 12 volts at both posts (which explains why the light won't come on)

Also the diagrams I have in my Haynes manual are the same as the ones on this page. They show a separate voltage regulator.

Is there a way to be sure which car I have ? (VIN decoding?)

Not sure if this leads us anywhere specific.

[This message has been edited by DEL (edited 07-10-2001).]

Just a shot in the dark...I had a similar situation in a '73T. The battery just ran down and the alternator checked out fine, but the light on the dash never came on. So someone suggested that I check to make sure there is good contact in the bulb holder itself. There wasn't and after I cleaned the contacts, the light came on and I never had charging problems again. The bulb appears to be in series with the charging circuit and as such must conduct to keep the circuit operating.

[Early_S_Man]

Dave,

There is a pic that should help find the regulator on p. 206 in Haynes. Yes, go ahead and cut the burnt ground wire until you get the charging problem fixed. The grounds are 'daisy-chained' along the instruments, so isolating it will help prevent more problems. It could be something simple, like a loose lamp holder that got cocked and shorted out when you wiggled the instruments.

I will try to scan the service bulletin about the alternator ... it may be a day or two, as Win98 decided to 'eat' or corrupt my SCSI card driver, and scanner has to have the SCSI card to work!

If you have a local dealer, try to pick up a copy of the 128 page 'Parts and Technical Reference Catalog: 911 Models 1974-1989' ... besides the other good info, it has the bulletin I mentioned on p. 110. It shows the ground strap on the alternator, and where it attaches to one of the 8 mm studs on the top of the case. i recommend that you install a ground strap ... it is recommended in the bulletin, too!

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Warren Hall
1973 911S Targa

[DEL]

Great info guys, thanks!

I'll see if I can't get some more literature here locally. Feel free to try and e-mail if it's easier than scanning.

quarter_miler@hotmail.com

Thanks again,


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Dave Loney
1982 911 SC Targa
1986 Buick T-Type 10.43 @ 129

[Ted Stringer]

Warren - that is what you get for useing win98! :-D As a user of scsi interfaces in all my computers I feel your pain. The only one I havn't had problems with in the new one (SCSI everything, fast box), than again it is running win2k.

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Ted Stringer
nuke3@juno.com
'84 911 Targa aka pocketrocket

[Early_S_Man]

Dave,

Here are the bulletin pages, and the Haynes page with Paris-Rhone alternator with built-in regulator:




From the lack of a ground at the indicator lamp, there is an open somewhere, because the ground has to come from the alternator, through the slip rings & field windings. Check the alternator for a fairly low resistance at Terminal 61. Add a temporary ground to the engine case and re-measure! The #61 lead has to go through the 14-pin connector (pin #11) at the bottom of the relay/fuse/CDI -unit 'console' or panel.
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Warren Hall
1973 911S Targa

[This message has been edited by Early_S_Man (edited 07-12-2001).]

[DEL]

Just an update and to see if there are any other ideas.

I grounded the blue wire in the gang-connector in the left rear corner of the car. I was told that this would isolate the problem of the battery light not coming on. They said if the battery light comes on I have a wiring problem in the engine compartment. If it doesn't come on the wiring problem is between the engine compartment and the dash. The light did not come on.

I also cut the brown wire that had melted. Not sure what was wrong there, I still don't see any reason for it. The pressure and fuel gauges work fine, can't tell about the temp and oil level gauges as the car was cold.

I also confirmed that I do infact have an internally regulated alternator.

If anyone has any further ideas, I'm all ears!

Thanks,
Dave Loney

[DEL]

Warren,

By the way I did get the Parts & Technical reference book. Great illustrations comparing the two styles of alternators.

On the testing of the wiring. When I remove the gauge and probe both sides of the bulb socket with my test light. It lights up on both sides. I'm confused as to how I could have an "open" in the system when both leads show a 12 volt source is present.

I'll try grounding the alternator and see if it makes a difference though.

[Early_S_Man]

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Warren Hall
1973 911S Targa

[Early_S_Man]

These two pics depict the '82 SC sircuit wiring with the Parris-Rhone alternator with integral regulator ... notice that there is a bit missing from the Pelican dwg above, and it is exactly where the alternator warning lamp is labeled!

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Warren Hall
1973 911S Targa

[This message has been edited by Early_S_Man (edited 07-11-2001).]

[DEL]

I should mention a couple other things I tried. I removed the alternator again to install the ground strap as per the bulletin. When the alternator was out I noticed it had what felt like a bad bearing (and the hits just keep on comin!) Anyway it's probably for the best because I ended up replacing the 4 day old rebuilt unit with an actual Bosch rebuilt which I assume is better. And they even warrantied the 4 day old one

I also jacked up the car and confirmed that the wires at the starter are tight, as well as the big ground strap from the trans to the body.

A good point was brought up on another bulletin board. Maybe my light bulb socket (for the battery light) is faulty. I'm going to check it out tonight.

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Dave Loney
1982 911 SC Targa
1986 Buick T-Type 10.43 @ 129

[DEL]

Just wanted to say thanks again. I pick the car up on Friday from the repair shop. They fixed the alternator (it was a wiring problem behind the dash) And they did a PPI. It also needs brake switches (for the brake lights?) and a vaccum advance assembly (the diaphram was bad)

Just over $500 which I can deal with. Other than that the car checked out great, good compression, etc.



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Dave Loney
1982 911 SC Targa
1986 Buick T-Type 10.43 @ 129