# My carbon monoxide detector always reads zero

**URL:** <https://boards.straightdope.com/t/my-carbon-monoxide-detector-always-reads-zero/490340>\
**Category:** Factual Questions\
**Created:** [March 22, 2009, 3:15pm UTC](https://boards.straightdope.com/t/my-carbon-monoxide-detector-always-reads-zero/490340 "2009-03-22T15:15:56Z")\
**Posts on this page:** 1\
**Page:** 2

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**Author:** ![Mr.Duality](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mr.duality/32/4098_2.png) [@Mr.Duality](https://boards.straightdope.com/u/Mr.Duality)\
**Post date:** [March 23, 2009, 4:06pm UTC](https://boards.straightdope.com/t/my-carbon-monoxide-detector-always-reads-zero/490340/21 "2009-03-23T16:06:59Z")

</div>

I took all three CO detectors outdoors and exposed them to exhaust from my ‘87 Dodge pickup. (The new ones have battery backup and I used an extension cord for the older one.) All three alarmed after a minute or two in the smoke. I should mention the ol’ Dodge burns some oil until the engine warms up. I find it curious that the two with digital display would not display any numbers while alarming but I didn’t want to play with them for a long time because it’s cold & snowy outside today.

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