Hellraiser944

Hello,

I have a US 944 (early Type 2 - California) and I'm going to remove the Cat
and O2 sensor for track use.

What coding plugs do I have to use on the DME-harness and on the
3-pin connector for the lambda-probe?

Thanks!

Kind Regards,
Johan

Hellraiser944

Anybody?

Found this site:
http://www.motronic.ws/4in1.htm

but don't want to risk burning my valves...

Hellraiser944

and up

KuroNeko

What are you planning to achieve by locating the sensors on the DME harness? Sorry if this sounds like a silly question, but I am trying to follow what you are saying. Are you trying to eliminate the missing sensor signal?

Hellraiser944

No, I know where they go,
I just don't know which ones to use or not to use.

The Californian 944 was delivered without plugs, an O2-sensor and a Catalyst.

Cars without catalyst had coding plugs, but different ones than other cars
with catalyst here in Europe.
There are also two types of blind plugs that go on the O2 sensor plug in
the engine compartment, one real blindplug and one that bridges 2 wires.

So there are a few different settings I can choose from when running
without the O2 sensor and catalyst.

The last thing I want to do is to make it run too lean and by that burning my valves, or too rich like I am doing right now without the O2-sensor,
which isn't healthy for the catalyst.

(the main reason for this is that the O2 sensor is shot and I have a
european exhaust lying around without cat and threading for the O2 sensor)

Eric_Oz_S2

What year car? If you let me know i can check the wiring diagram and tell you what plug you need.

Hellraiser944

Hi Eric,

First registration is 30/06/1986.

Thanks!

According to motronic.ws, I think I just have to use
the impedance adapter 1.8Kohm 944.612.421.00 on the DME
side of the wiring harness (under the floorboard).
Then there's the question of the plug in the engine compartment.
Leave it running in open loop or bridged .

Eric_Oz_S2

OK, here are the relevant diagrams.





You need to remove the coding plug (if you have one as per Cal cars) and put a variant plug (impedance adaptor) in so that it is as per R.O.W. As the altitude switch uses the same spot as the variant plug in the US cars, you may not have the "socket" wired into the harness. It is certainly there in ROW cars, but I really don't know for US (just look). You can see it by removing the footboard. It will be a white socket not far from where the wiring harness connects to the DME (can be hard to see). If not, you should probably pull the altitude unit and use these wires to wire in a resistor. I 'think' the resistor used is 1 kohm, but cannot be sure. You could always but the part from Porsche to be sure.

You also need to bridge pins 1 and 3 of the plug to the O2 sensor.

Hope this helps.

Hellraiser944

Thanks ! This sure helps!