Wiring question

adam911 · 08-01-2010, 12:27 PM

Hi there,

I've just fitted a 71 engine to my 69 911E. The wiring changed after 69 so I am equipped with 2 wiring diagrams. I am having a bit of difficulty wiring up my alternator. The harness connected to the alternator on the engine was different in that it had a terminal block on the end which wasn't compatible with connectors on the electrical mount plate (where the volt reg,relays and rear fuse box is mounted) in my engine.

I removed the terminal block and spade connected the wires that required them.

I have my black, brown and blue connected to the voltage regulator. I then have a thick red wire that connects to the rear (3 fuse) fuse block.

I then have a red wire left over. According to the 69 wiring diagram this red wire should go to the voltage regulator and connect to the same spade as the blue wire.

Now, I'm aware this could be a costly mistake, so I just wanted to run it by someone before I continue and connect both the blue and red wire together on the same connector on the regulator.

Any guidance would be most appreciated.

Adam

brd · brd's Garage

Any pics?
Maybe a redundant question... but to be sure... has the alternator been upgraded to an integrated regulator model?

BRD

adam911 · 08-02-2010, 05:12 AM

Here's a picture of the rear of the alternator when I was checking the connections, I believe that it isn;t the upgraded type.

86 911 Targa · 08-02-2010, 07:37 AM

Quote:

Originally Posted by adam911

Hi there,

I've just fitted a 71 engine to my 69 911E. The wiring changed after 69 so I am equipped with 2 wiring diagrams. I am having a bit of difficulty wiring up my alternator. The harness connected to the alternator on the engine was different in that it had a terminal block on the end which wasn't compatible with connectors on the electrical mount plate (where the volt reg,relays and rear fuse box is mounted) in my engine.

I removed the terminal block and spade connected the wires that required them.

I have my black, brown and blue connected to the voltage regulator. I then have a thick red wire that connects to the rear (3 fuse) fuse block.

I then have a red wire left over. According to the 69 wiring diagram this red wire should go to the voltage regulator and connect to the same spade as the blue wire.

Now, I'm aware this could be a costly mistake, so I just wanted to run it by someone before I continue and connect both the blue and red wire together on the same connector on the regulator.

Any guidance would be most appreciated.

Adam

Try this.

adam911 · 08-02-2010, 11:06 AM

Really need some help with this.

I have the manual above, but it doesn't show the pre 72 wiring diagrams and I already have the correct wiring diagrams for both the 69 and the 70/71 models.

Anyone

adam911 · 08-04-2010, 12:45 PM

According to my wiring diagram the secondary smaller red should go to the rear fusebox to power the rear window demister.
However, I now have the engine running and the ignition light is staying on.

Can anyone tell me the best way to test the alternator?

Thanks

Adam

304065 · 08-04-2010, 01:47 PM

You connected the B+ to the D+/61, no wonder the light won't go out, and the alternator's not charging the battery, either. I bet if you check the battery voltage with the engine running it's only about 12.5v.

The fat red wire from B+ should go to the starter 30 terminal, the same one the big fat black one from the battery connects to. That way current can flow to the battery and charge it.

The thin red wire goes to the rear fuse box, fuse #3.

Search here for "blue wire" for more information about how the charging circuit works. I would have tried to use the engine harness from the '69, it's a one year only thing.

Needless to say, be extremely careful working around the battery and alternator wires, you can kill yourself with the amperage or burn the car down.

Good luck!

adam911 · 06:31 PM

Sorry, I'm not completley clear on that. Are you saying the way the alternator is wired in the piture is incorrect?
As I didn't touch that, it's as it was when I took the shroud off.

I checked the voltage at the battery with the eninge off and it's 12.35v. With the engine running it's 11.98v, so I'm assumung that would suggest it's not charging.

When I was looking at the picture it dawned on me this alternator is a motorola and the old one was a bosch. The regulator in the car was a bosch, so I swapped it out for the motorola one and ancilaries that I had. Didn't make any difference though. The light is on with the ignition and stays on when the engine is running.

Is it possible to check the alternator at it's wiring, as opposed to at the battery?

I wasn't able to use the 69 harness, as it went with the engine.

My B+ goes to the starter via the brass terminal bar by the fuse box (60 on the wiring diagram).

The thin red wire isn't connected, as I don't have a heated rear widow (fuse 3 on rear fuse box).

The blue wire (D+61) goes to the voltage regulator and judging by the wiring diagram, goes to illuminate the charge light in the dash.

Thanks

Adam

adam911 · 08-06-2010, 06:32 PM

Bump

304065 · 08-07-2010, 08:20 AM

Adam, before you do anything else, tape off that second B+ red wire and insulate it from shorting against the body sheet metal. If that touches ground you will have an 800 amp arc welder on your hands.

I don't think it's the alt connections that are wrong-- to review

Brown D-
Red B+
Blue D+/61
Black DF

It's the connections at the other end that are wrong. You need those same colors to go to the voltage regulator

DF- black-terminates at DF terminal on reg
D+/61- blue goes first to D+/61 terminal on VR and then to the bulb holder in the oil pressure gauge. Other side of bulb holder is switched +12v, probably a red/black wire.
D- ground- goes to D- terminal on VR

Your alternator is not charging. Battery voltage should be 12.5 or better, at 12.3V your battery has only 25% charge. Put the battery on the charger for THREE DAYS nonstop, monitor the charger and connections, you don't want to cause a fire.

Can you post a photo of your electrical console?

Good luck!

adam911 · 09:47 AM

Thanks for the reply.

I've taken a couple of pictures. Excuse the wiring as I haven't tidied it until I get everything working correctly.

As a note I swapped out the Bosch regulator for the motorola regulator and capacitors.

What concerns me is in this post and in other posts I have read on this forum, is that I only have the blue wire coming from the alternator into the VR and no second blue going from the VR elsewhere. The 69 and 70-71 wiring diagrams show a second blue from the VR to the idiot light on the dash. I don't have this second wire and am having trouble understanding how the idiot light is illuminating.

Below are a couple of shots of the electrical console with the alternator wires marked.
There is no connector on the motorola VR for the brown D-. On the electrical console from the 70-71 car the engine came from the brown D- went to ground on the panel, so I have replicated this.

I have tied off and insulated the spare red wire (rear window defrost) and will ultimately connect it into the fuse box in order to tidy it.

[IMG]

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Thanks again

Adam

304065 · 08-07-2010, 09:58 AM

Adam,

You actually have a fairly complete 1969 electrical console there, congratulations!

Complete with the one-year-only and no longer available "slow-acting relay," that's the black cylinder that says "nicht werfen" on the other side. Don't throw it.

OK, this problem just got simpler. In order for the charging circuit to work you MUST have a connection between the bulb holder in the dash and the D+/61 terminal on the voltage regulator that then runs over to the D+/61 on the alternator.

Search my name for "blue wire" for more info, but basically what happens is this

You turn the ignition on, current flows to bulb holder
current flows through bulb and out other terminal of bulb holder to blue wire
current flows back to VR
With the alternator not turning, no current is present on D+/61, so the bulb illuminates, telling you the alternator is not charging. The VR senses this and sends +12V through the DF (dynamo field) black wire, which energizes the field.
You start the engine, field begins to turn, inducing a current in the stator, which is rectified by the single output diode in your motorola and gets fed BACK to the VR D+/61 terminal.
With +12V coming FROM the alternator and +12V coming FROM the battery, the voltage is equal more or less on both sides of the bulb in the dash, and no more current flows
The light then goes out.

With the alternator charging, the "idiot light" does not illuminate.

So where is your blue wire circuit? Gotta get up behind the dash and find out. If it doesn't terminate in the engine compartment, it terminates somewhere! You can even rig a long jumper between the bulb holder's blue wire and the D+/61 on the VR for testing purposes if you want.

Good progress! When this is done we'll set about cleaning up the '69 electrical console so it looks right.

That motorola VR is a museum piece, while you are correct they should match, it's an old electromechanical type, you may want to pick up a Transpo IT201 for testing, or use your bosch. While the "set-point" is different it won't kill you for testing purposes to use a known good VR.

adam911 · 11:04 AM

I had read you other posts re the blue wire and they made perfect sense to me, which is why my lack of a second blue is all the more puzzling

Ok here's what I did.

Pulled the blue wire from the idiot light (note the other terminal on the idiot light has a blue/yellow wire as per the 69 wiring diagram).

Connected a piece of wire to said blue wire and ran it to the back of the car. Set my ohm meter to 200 and tested between my extended blue and the terminal on the capacitor that the blue wire connects to. I got a reading of 82 ohms. Naturally when I test the blue wire running back to the alternator I get no continuity, as to be expected.

Now when i test between my extended blue wire (from idiot light) and ground in the engine bay I get a reading of 28 ohms. Now electrics aren't my strong point (as you may have noticed), but that suggests to me my blue wire from my idiot light is grounding somewhere.

Since writing the above I have now found the end of the blue wire in the engine bay, it was plugged into a weco connector that had a yellow wire on the other side that disappears into the loom down by the console. I'm assuming this in incorrect.

So, should I now take found blue wire and piggyback it onto the connector on the capacitor that then goes to the D+/61 on the VR and reconnect the other end at the idiot light?

What do you think?

Adam

adam911 · 08-07-2010, 11:36 AM

Ok piggybacked the 2 blue wires tigether and connected to the VR and voila....light goes out and I have 14.76 v at the alternator.

Now to find out what should be plugged into the yellow wire that the blue wire was mistakenly plugged into.

304065 · 08-07-2010, 04:32 PM

Adam,

When in doubt you can eliminate all the capacitors from the circuit- those are noise filters intended to meet the German VDE RF emissions tests- they are electolytics. The odds of them still working are pretty slim, 41 years is a long time. You should be able to go straight to the VR.

Anyway glad you have it working. 14.76 volts is pretty high, you really should charge your battery for a couple days. The alternator was not designed to bring the battery back from 25% charge, and it will try, but will get VERY hot and those alternators aren't known for their reliability. This is also why you shouldn't jump-start the car unless it's a genuine emergency-- it's likely to kill the alternator.

Once you charge the battery the charging voltage should settle down, if it doesn't, then look into a replacement VR-- 14.76 is just about "full-field" voltage, i.e. the voltage regulator is powering the field pretty much all the time, as opposed to periodically which would reduce the charging voltage.

When I hear about yellow wire, I think "Starter 50 terminal." But I would have to look at the 69-only diagram to be sure, and the link to the 69-only diagram seems to be down.

please help with tach

adam911 · 09:11 PM

I'll take your suggestion about charging the battery. My charger has a light comes on when it's charged. I wonder if it continues to charge once the light comes on.

There are 2 yellow wires from the starter according to the diagram. They originate at the same pole (starter 50). One goes to the ignition switch and one goes to a terminal, splits and goes to the time limit switch and the temerature switch (start). I'm not sure what those are, but I suspect it's something to do with the MFi which is no longer on this car.

Thanks for the advice, it was a great help.

Adam

304065 · 08-08-2010, 06:24 AM

I figured as much, the factory used solid yellow for the cold-start stuff. FYI, when the starter is cranked current gets sent to the two thermo-time switches (there are 2 in a 69, 1 from 70-on) and depending on the temperature, they send current to the cold-start solenoid on the MFI filter console. You should tape them off and electrically isolate them from the rest of the harness.

I have been looking for a good 1969 "reference" for you, haven't been able to find a factory photo of the early console. Here's the best thread we have on the subject. . .

Early Engine Bay Electrical Panel Restoration

adam911 · 08-08-2010, 07:46 AM

Great thanks. In fact you can see the yellow wire I was reffering to in the very first picture on that thread. It's sat right under the console below the red with white stripped wire. I shall cut the connector off, heat shrink it and tuck it way. I'll also do away with the capacitors too. As you said they're probably not working anyway.

Your second to last post with the link (please help with tach" brings me to another problem I have. When I first got the car the tach worked eratically and in no way represented true RPM. The car has an MSD 6200 installed and a tach adaptor, though when I got the car both the MSD unit and the tach adaptor were just sitting on the rear logitudal section under the bulkhead. I have since made a mount for them and mounted them to the rear bulkhead.

I have checked the wiring on the MSD unit and the tach adaptor. It appears to be correct and yet it still behaves the same. Won't move above 2000RPM and only seems to reflect true RPM at idle.

I read on the MSD site that there are 2 tach adaptors 8910 (white wire trigger) and 8920 (magnetic trigger).
I took my tach adaptor off and there are no markings on it whatsoever, so it;s hard to tell if I have the correct one or not. I guess maybe this is a question for MSD. I'll see what they say.

Adam

304065 · 08-08-2010, 10:19 AM

See the little silver can that says "einbau senkrecht klemmen unten?" That is your "tach adapter" to drive your 1969 tach off a Bosch CDI, which is what the 911E came with. The wiring diagram shows how it's connected or you can find it in this thread : SWB Relays Analyzed - Page 2 - Early 911S Registry Bulletin Board
It's the diagram that says "warning CDI output. . . ."

Now, your MSD box has a 1/4" faston connector in the side that is a tach driver circuit, it's a 20% duty cycle with a 12V square wave. It works OK to drive later tachs, but your 69 Tach needs a 24V square wave (more like hundreds of volts). So the "tach adapter," the little red box you see in on your plate on the firewall, well, that's basically a doorbell transformer in a fancy case-- it's function is to charge up when the points are closed, then when the points open, it creates a big, noisy, dirty "back EMF" that triggers the tach. A wiring diagram for that sort of thing is here: Tach - oh - woe (pre '74) It's the one that says "diode may be optional."

The induction coil tach adapter is electronically crude: a better solution, if you wish to use MSD, is to send your tach to North Hollywood Speedometer and have them convert it for MSD use, this is about $150, and they can fix the movement, etc. Or if originality is important (it is to me) you can source a replacement tach inexpensively and have them convert that one, as well as screening the face with whatever design you want, different redline, etc. Given that they are changing the board, you could even send them a cheapo 912 or 914 tach and they can make it work.

adam911 · 08-08-2010, 05:08 PM

Have my tach converted, buy another and have it converted or buy a post 71 tach?

I'm unable to read what's on some of the cans on the console. I've colour coded them below and I believe you to be talking of the "blue" one, but I want to be sure, as I can't rely on the colour of some of the wiring, as I've come across a few anomolys.

Adam