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Posted by: Morph914 Apr 14 2021, 06:37 PM

I just noticed I do not have the thermo time switch. Since I live in FL and will only drive in fair weather, can I go without this piece? From what I gather this sensor activates the 5th fuel injector during cold weather.
We occasionally get freezes here, but I wouldn’t be driving in these conditions anyway.

Here is the bracket that holds the thermo switch.

Posted by: BeatNavy Apr 14 2021, 07:01 PM

Yes, your assumptions are correct. You can do without it.

Posted by: robkammer Apr 15 2021, 10:50 AM

Maybe a dumb question, but a fifth injector?

Posted by: bdstone914 Apr 15 2021, 11:20 AM

The thermo time switch give a signal to the cold start valve ( fifth injector ) at temperatures around 40 degrees F to fire for a few seconds to assist with cold starting.

Posted by: Morph914 Apr 15 2021, 12:59 PM

Thanks guys

Posted by: 914_teener Apr 15 2021, 01:17 PM

Just don't call your car a Challenger and you'll be fine.

Posted by: JeffBowlsby Apr 15 2021, 05:10 PM

A couple thoughts:

The Thermoswitch can activate at temps colder then ~40F, some of them down to 0F depending on the switch and on the assumption that it works at all.

311 906 161 : -12 to -18 deg. C / 10 to 0 deg. F
311 906 161 A : 0 to -10 deg. C / 32 to 14 deg. F
311 906 161 B : -2 to -8 deg. C / 28 to 18 deg. F
311 906 161 C : -6 to -14 deg. C / 21 to 7 deg. F

When cold enough to activate and only when the engine is cranking, it creates the ground circuit completing the electrical signal circuit which activates the cold start valve, a special type of injector, often called the 'fifth injector'.

In summer and in warm climates it is not needed and does not activate. But one might also consider removing the valve, and blocking off the air plenum mounting hole, to prevent richening the fuel mixture in the event the valve leaks, because it is still under fuel pressure even when not activated.