US DME in ROW '84 911 with US 3.2 Engine

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OK, so as I continue to work on my car, I've done a fair bit to the engine to get idle squared away including changing vacuum hoses, manifold gaskets and reference sensors. All seems to be working well now, less the cold start which is still rough for the first couple of minutes to the point where I have to throttle up to keep it from stalling out. It's an ROW vehicle that has a US '86 3.2 with cat and O2 sensor, but there is no connector from teh engine bay to the DME to connect it. After checking the DME to see what version it was (Bosch: 0 261 200 050 / 911.618.111.05), which after some research here, it seems to point to a US / Japan DME as well. That said, what is the effect if the DME "thinks" there's an O2 sensor, but in fact it has no connection to get a signal back to adjust. Couple of questions:

(1) Is this a major issue?
(2) Should I try to run a wire from the O2 sensor (2 wire) to the DME connection point?
(3) Does it really make a difference to cold start?

Thanks

[E Sully]

Not a major issue. It did not affect my cold starting. It will run fine without the connection. When I purchased an '86 engine for my car, it came with a Euro harness with no O2 wiring. It ran very nicely without the connection till I added it in a month later. The O2 connection is 3 wires, due to the fact it has a heater circuit to speed up the warming of the O2 sensor.
Here is a link to my car before the O2 sensor install, it shows a cold start at the beginning.
1973 Porsche 911 - YouTube

[Skip1]

Thanks a lot for the reply. That gives me a bit better feeling. Did you just run a wire in parallel to the harness from the DME to the O2 sensor connection in the Engine Bay?

[McLaren-TAG]

My car has had an O2 sensor delete at some point during its life, no issues. When I ordered my S Wong chip, I had that discussion. Steve mentioned that the DME will use the signal from the sensor if it sees it, and live without it if it doesn't see a signal.

[Skip1]

Thanks both. Guess I'll live without it for now. Just wondering if I need to adjust the AFM as a PO has removed the adjustment screw cap, and it smells as if it's running rich to me.

[jager911]

Same here, installed an '85 3.2L in my '74 in 2003 without the O2 sensor, car starts fine, programmed to run slightly rich with Steve Wong chip for track use. I think it would affect emissions more than performance.

[Mark's 86]

Is there any problem in deleting the o2 sensor and running open loop like the European cars? I am planning on a CAT delete and am considering deleting the o2 sensor as well on my 86 Carrera. Where I live there is no requirement for emissions testing. Just wondering what the Pros/cons are of deleting this system.

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So, from my perspective, this is my configuration:

'84 ROW (German spec)
'86 3.2 L California engine with US DME installed
No O2 sensor wiring harness between DME and engine bay
O2 sensor bung and wire just tied off in the engine bay
No performance chip - stock DME

Appears not to be an issue and based on everyone's comments thus far, seems more than viable. I'm planning on a CAT bypass in the future or perhaps just clean out the old CAT housing (don't expect it's doing much anyway) - cheaper with the same effect I would think.

[A&F]

Won't that destroy your fuel economy however?

[Skip1]

Since posting my last comments, I've had a new rebuilt engine installed, sport CAT and full tune. Runs great, pretty decent fuel economy from what I can figure (average of 10 litres per 100 kms.