What happens if I ???

[Gordon Rankin]

I am thinking of cutting the line to my O2 sensor until I get my exhaust manifold fixed. Will this cause the sensor just not to operate or will it hike up the fuel or the Oxygen?

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Gordon
1981 924 N/A

[AFJuvat]

Will cause all sorts of unplesant idle/running problems.

I wouldn't advise doing it

AFJuvat

[mlue]

I Gordon, when I had problems passing my emmissions I played around with a few things one been the O2 sensor. Unplugging the O2 sensor on my '86 944NA causes it to run rich with poor MPG. The car drove and idled fine! My mechanic said that the electronics probably sensed the lack of an O2 sensor after the first minute or so and defaulted to preprogramed fuel and spark advance settings. I donn't know if an '81 924 would react the same but if it's as easy to unplug as the 944 give it a go.

If you have a CAT, running extremly rich for an extended peroid of time can burn out the CAT.

Mark
'86 944NA

[JonA]

Gordon,
My understanding is that you cannot disconnect the o2 sensor because the brain thinks it is a very rich or lean (I dont know which) condition and adjusts. What I did was to disconnect the temp sensor that holds the Lambda function off until the car reaches operating temp. The Lambda thinks the car is always cold and therefore does not function. It is loacated under the coil. Mine is an 82 but I believe you have the same logic. The leads are blue/red and brown. I also disconnected the frequency valve, located under the fuel distributor to remedy an erratic pressure condition (I think the brain is bad or maybe a connection somewhere) and the car now runs with pure mechanical fuel injection. It has no supplementary electronic fuel enrichment and so the acceleration may be suffering slightly but otherwise it runs fine. I have another brain and I am going to switch and put everything back together this weekend.
Check Haynes pg. 292.
Hope this helps.
Jon