Starter Wiring Help

[arbita1]

I probably should have take a picture before I disconnected the starter wiring, but I figured the wiring diagram would be clearer.

I'm a bit confused on the wiring because there's some kind of square device that is bolted to the underside of the body next to the starter that shares wiring with it. I don't really see it on the Bentley or factory diagrams. What is this device?

Anyone have a picture of the wiring in this area? Thanks.

[RoninLB]

wild guess is that it's a relay

[al lkosmal]

Matt,
I can't picture what you mean by some sort of square device. Can you post a picture of your starter, wiring and the square device. I have only had fairly early 911's, so your SC may be different, but I can't recall there being anything more than power from the battery, power to the alternator (both of these are typically large gage, red wires that connect to the starter post....and the yellow wire with a flag terminal, which switches power to the starter/solenoid.

post some pix and we'll see if we can get you going.

[Gunter]

Year and type and pix always helps.

If it's an SC, someone may have added a relay to reduce the load on the ignition switch.

Meaning: One of the yellow wires from the IS would energize the relay, which transfers power from the main starter terminal to the Solenoid post where the yellow wire would have been before the relay was installed.

The second yellow wire (for the cold-start circuit) stays on its usual Solenoid connection.

[arbita1]

83 SC.

What is this?

[psalt]

Matt,

Looks like a photo of a FORD starter solenoid.

[Gunter]

Interesting.
Please, post a picture of the actual starter.

[arbita1]

[47silver]

you do not need the solenoid that you show in the picture if you have a porsche starter as it has a solenoid. They may have used this solenoid as a relay from the key to the solenoid start terminal but I cannot be sure.
See this diagram from Pelican.


you need \
1 thick red power from the batter to the main lug.
1 yellow wire from the key to terminal 50 this engages the solenoid and powers and puts power to the starter motor.
1 yellow wire that runs through the firewall to the cold start valve.
1 smaller red wire runs from the large main lug to the alternator through the firewall.

[Gunter]

Do you have 2 yellow wires? And one black and one red heavy wire?

Normal set-up would be 2 yellow wires (one from the ignition switch, one for the cold-start circuit) going to the spade connector (s) on the Solenoid.
2 heavy black/red wires go together on the threaded terminal.

For some reason? an auxillary Solenoid was added. But why? To reduce the load on the ignition switch?

Provide ground to the starter case and test the Solenoid on the starter by connecting a wire with an aligator clip to the spade connector and then connect the other end to a 12 V source.
Careful!!! It'll spark a little.
Make sure the car is out of gear because the Solenoid should engage and spin the motor!

[arbita1]

Yes. I have all those wires. See pic.



The red and two yellow wires are there. The black one is on the car. It looks like the thick yellow wire was modified to a different connector so it could be attached to the "Ford" solenoid. The yellow wired on the solenoid in the other picture has a spade connector on it.

No idea why it would be like this. I never had any starting problems though. Maybe I should connect it back to stock and see what happens or just leave it and not tempt fate.

Can I do Gunters test while the engine is out?

[Gunter]

If the starter has many miles/hours on it, this would be the time to service/rebuild because later it's more difficult to get out. The top Allen socket bolt is hard to reach.

I believe the Ford Solenoid was added to reduce load on the ignition switch.

Follow the wires from the Ford Solenoid.
Where is the red wire on it going to? In other words, where did the power to it come from?
And does the yellow wire have a female end on it for the male spade connector on the Bosch Solenoid?

[arbita1]

Originally Posted by Gunter

If the starter has many miles/hours on it, this would be the time to service/rebuild because later it's more difficult to get out. The top Allen socket bolt is hard to reach.

I believe the Ford Solenoid was added to reduce load on the ignition switch.

Follow the wires from the Ford Solenoid.
Where is the red wire on it going to? In other words, where did the power to it come from?
And does the yellow wire have a female end on it for the male spade connector on the Bosch Solenoid?

I can't rebuild right now. I have to get the engine in and the car back in my garage before the winter.

The yellow wire on the Ford solenoid has a spade connector on it which connected to the Bosch solenoid. The yellow wire on the engine wiring harness (the fat one) was connected to the Ford solenoid. (Second connector from the right of the solenoid.)

The red wire on the Ford solenoid was connected to the Bosch solenoid along with the red wire on the engine harness and the black wire from the battery. So power came to the normal place on the Bosch solenoid and then fed the Ford solenoid.

What do you think?

[psalt]

What do you think?
__________________


Matt

My "guess" would be that the PO had starter problems, attempted to solve them with a rebuild (part number.....X), and when the symptom came back, fitted the FORD solenoid to increase the voltage to the Bosch solenoid when cranking. If you are unfamiliar with the 911's starter issues, search and read the archives. As the Bosch starter ages, it becomes sensitive to voltage drops and develops an intermittent problem. The 911 has voltage drop problems because of the distance from the key to the starter , the many connections along the way and in the 83SC, the A/C relay in the circuit. The Bosch rebuilds often fail to resolve the problem because the rebuild does not address the problem area. Now that the cores are all over 20 years old, my advice is to put it back the way it was or get a Japanese gear reduction starter. A smart $8 addition is an engine compartment cranking button. The 911 starter is hard to reach in the rain at night and the button will often get you going.

[911pcars]

Originally Posted by psalt

What do you think?
__________________


Matt

My "guess" would be that the PO had starter problems, attempted to solve them with a rebuild (part number.....X), and when the symptom came back, fitted the FORD solenoid to increase the voltage to the Bosch solenoid when cranking. If you are unfamiliar with the 911's starter issues, search and read the archives. As the Bosch starter ages, it becomes sensitive to voltage drops and develops an intermittent problem. The 911 has voltage drop problems because of the distance from the key to the starter , the many connections along the way and in the 83SC, the A/C relay in the circuit. The Bosch rebuilds often fail to resolve the problem because the rebuild does not address the problem area. Now that the cores are all over 20 years old, my advice is to put it back the way it was or get a Japanese gear reduction starter. A smart $8 addition is an engine compartment cranking button. The 911 starter is hard to reach in the rain at night and the button will often get you going.

+1. However that Ford starter solenoid is kinda overkill - typically used to switch heavy starter motor current. A regular Bosch-type 25A relay is sufficient.

Here's mine squeezed into the rear tunnel:


More here:
Remote Starter

Sherwood

[Gunter]

Good stuff from Paul and Sherwood.

Agree that a 25A Bosch-type relay would be better to reduce the load on the ignition switch instead of the Ford Solenoid.

Sherwood,
Thanks for the picture and details.
I believe the Control wire from switch to relay should be (86) on the relay, not (85)?

arbita1,
I understand the haste to get the car into storage. Wire connections come after the engine is installed anyway. I recommend using dielectric grease on all electrical connections, especially the 6 and 14 pin connectors. It prevents corrosion but some people say it reduces current flow. I use it without problems but Vaseline also works quite well.

In case the starter has to come out later, I suggest to crack open the upper Allen bolt, use some Never-Seize on the threads and tighten again.
When my starter developed problems described by Paul, I took it out and serviced it myself. It's mostly the Bendix mechanism and the Solenoid plunger needing lube that I recall.
I also installed the 25A relay desribed by Sherwood.

If you just want to get it going, wire it the way it was and make changes later.

[911pcars]

"I believe the Control wire from switch to relay should be (86) on the relay, not (85)?"

Gunter,
Correct. There's a typo on the photo. If the control path to the relay is 86, then the path to ground is at 85 (or vice versa).

Thanks,
Sherwood