Won't run with O2 disconnected.

[Andy_]

I'm trying to sort my mixture which is very rich. I plugged in my dwell meter, warmed the car up with the fans running, but forgot to disconnect my o2 sensor.
I found the car won't start without the o2 connected. I'm guessing the lambda has been compensating for the rich mixture, which is so rich the car can't start without it.

How do I get it back to a point where I can adjust the dwell? Turn the mixture anti-clockwise until it stalls with o2 connected, then back a bit?
Any more technical / sensible idea appreciated.
Thanks

[Andy_]

Quick thought.
I don't have a ir gas analyser. I do have a duty cycle meter. Could I go this way to get it back?

[Horsebox]

How are you disabling the 02 sensor? Disconnecting just the sensor itself behind the driver side rear wheel or by unplugging the entire ECU behind the drivers seat?

What you describe sounds a bit odd, it doesn't take the mixture to be very far out at all before the lambda ECU rejects the o2 sensor information and just sets the duty cycle of the frequency valve to its default 50%.

[Ron]

How do I get it back to a point where I can adjust the dwell? Turn the mixture anti-clockwise until it stalls with o2 connected, then back a bit?
Any more technical / sensible idea appreciated.
Thanks
The O2 sensor is useless when the engine is cold.

Have everything connected. You must let it run until it warms up (fans kicked on). If it is rich turn the CO screw counter clockwise until the dwell meter swings a little above and below 40°. Note it is very very touchy...you can go from too rich to too lean when turning it more than a nudge (which might make you think it is not responding to your adjustments). Be sure to plug the hole and wait for it to settle on the final adjustment.
Do the other tests later (lead disconnected, grounded, etc).

If it is way off, you might keep it running by pressing the plate down slightly while working the throttle....

Read this for background info (http://dmctalk.org/showthread.php?5760-Adjusting-CO-With-A-Dwell-Meter)