Wiring Diagram 911SC 3,0 1980

[der_bodo]

Dears,

I am desparatly looking for a wiring diagram for my 1980 SC US-Model.

I went through the forum and found the 1979 and 1982, but actually they seem to be different, at least the fuse box layout is. My focus is on fusebox and instruments, as I do have a shortcut on fuse 4, which is interior light, clock etc.

Funny enough - when fuse4 jumps out, the car starts to stutter around. I do have no idea. There are two cable coming off fuse 4. One is interior lights+clock - the other.. I don´t know.

However, it would of course be cool to have the full picture

Would be great if someone has something!

Many thanks from Germany,
Bodo

[Schulisco]

The 1980 SC was the first 911 with electronic lambda control. The box is under the passengers seat. The fuse #4 supplies also this box. When it's broken no power supply is there and lambda control is fully out of service. Esp. the cycle valve doesn't operate any more, which manages the fuel distributor pressure. Do you have an oxygen sensor ("Lambdasonde") still installed?

Refer to Andrews (user AndrewCologne here) fabulous website according those engines:
https://nineelevenheaven.wordpress.com/der-911-us-sc-3-0-motor-mit-g-kat/

Schematics you find here:
https://classickabelboomcompany.com/wiring-diagram-porsche/
Unfortunately not for the 1980 model, but you can use them of the '81-'83 models. There only slight differences, I suppose your car doesn't have the acceleration box (an additional electronic box which enrichens the mixture for 2secs on accelerating, but no necessary for older cars)

Thomas

[der_bodo]

Hey Thomas,

wow, that helps me a lot, thanks!
Until today, nobody could explain why the car won´t run properly when Fuse #4 is out - especially as the fuse carrier does not mention the lambda control box.

The shortcut is somewhere in the interior light/clock circuit. As soon as I take the respective cable off, the fuse will retain. So this mistake will be detectable.

I do not have a lambda installed nor accelaration box.

[Schulisco]

Welcome Bodo. :-)

Then your lambda control unit incl. the frequency valve (located at the front side of the engine, hidden in the back when standing behind the car) is somewhat aputated. This means the control box operates the frequency valve in the "limb home mode" meaning that it is operated at 50% duty cycle without the signal of an oxygen sensor. This is a emergency mode to get home when oxygen sensor is bad. So this will cause lower performance and higher fuel consumption.

Unfortunately often seen on these cars coming back to Germany....

Thomas

[der_bodo]

I just went through AndrewCologne´s (hello, neighbour) explanations - rabbit hole, juhuu. This will probably be pretty helpfull. I will do my best to get through this...!

Thanks again - surprising knowledge on my car, after owning it for 14 years.

[wazzz]

A Workshop Manual is available as a pdf for CIS 911. It contains diagrams for 78 and later years (81 and more).
For the SC 80, the only diagram I found in this book is a supplement called "Additional Current Flow Diagram, Type 911 SC USA, Model 80". This supplement deals with the Oxygen Sensor System.
I can make this pdf available as a wetransfer link if you want it. Let me know.

[Bill Douglas]

Bodo, the Euro cars - ROW cars are different to the USA cars and we don't have lambda stuff. I don't think mine has an oxygen sensor either.

[der_bodo]

Originally Posted by wazzz

For the SC 80, the only diagram I found in this book is a supplement called "Additional Current Flow Diagram, Type 911 SC USA, Model 80". This supplement deals with the Oxygen Sensor System.
I can make this pdf available as a wetransfer link if you want it. Let me know.

Hi Gilles,

a PDF of exactly that supllement would be great, as the oxygen system is the part causing the trouble - though I belive the shortcut is in the other fuse#4 circuit.

@Bill: Honestly I am not absolutly sure. I have no catalyst but an empty tube - but about the oxygen sensor/lambdasonde I will have to have a look again, if it´s still there or not.

[Schulisco]

Bodo, you got e-mail ;-)

[wazzz]

Ok, here is the wetransfer link to the manual. It should remain available for 1 week. Anyone can download it.
Hope this helps.

[Funracer]

Originally Posted by wazzz

Ok, here is the wetransfer link to the manual. It should remain available for 1 week. Anyone can download it.
Hope this helps.

I got it. Thank you.

[timmy2]

1980 Lambda:

[der_bodo]

Originally Posted by wazzz

Ok, here is the wetransfer link to the manual. It should remain available for 1 week. Anyone can download it.
Hope this helps.

That helps a lot - thank you so much!

[Schulisco]

Originally Posted by Schulisco

Bodo, you got e-mail ;-)

Here's an additional link to an original technical instruction from Bosch about the lambda controlled CIS / K-Jetronic injection system:

https://files.bmwclassic.nl/E21/K-Jet/Bosch_K-Jetronic_web.pdf

It explains very well how the system works in general. It's a pretty rare version because it explains the lambda control as well. Mostly you find the "simpler" versions on the net without lambda. Never seen before on the net...

German version also available ... ;-)
http://vincentloirat.free.fr/KE-Jetronic/bosch_ke-jetronic.pdf

Thomas

[wazzz]

Originally Posted by timmy2

1980 Lambda:

That's the diagram I was referring to. It is on page 827 or 828 of the pdf I uploaded to wetransfer and linked above.

[bob_cote]

How many pages is this workshop manual pdf that’s available for download? Thanks.

[wazzz]

Bob, 1005 pages. File is about 65MB. This is the complete WM for CIS cars, not just the electrical.

[bob_cote]

Thanks very much. Just wanted to make sure I got the whole thing. Happy New Year to all.

[uncRowin]

Hi, would someone be willing to post a link to the pdf of the workshop manual again? I am building a new harness for a 1980 SC and it was exactly what I need to answer a few questions.

[wazzz]

Originally Posted by uncRowin

Hi, would someone be willing to post a link to the pdf of the workshop manual again? I am building a new harness for a 1980 SC and it was exactly what I need to answer a few questions.

Here you go: https://we.tl/t-t2XKKFx5EF

Should be valid for a week from now.