What is this and what does it connect to?

[66MonacoWagon]

In the lower left hand corner, cylindrical part. I have a vacuum hose coming out the end that is not connected to anything, and it looks like there might be another port at the top. It is a 71 440 - I'm still learning on this one...

Many thanks
Joe

 

[ceebuddy]

Seems like your 1971 is a California car and has the NOx Sytem put into cars sold in California that year. The cylindrical item is part of the NOx system and is a solenoid vacuum valve. It disrupts vaccum to the distributor vacuum advance under certain conditions, i. e. if accellerating under 30 mph. You should also find a thermal switch mounted to the firewall in this car.

 

[Davea Lux]

Most of this style NOx devices were disconnected because of performance issues. They tended to not work as designed and often completely disabled the vacuum advance leading to sluggish performance and lousy gas mileage. Most likely why yours is disconnected. Check to see if the vacuum advance has been rerouted to a throttle plate port.

Dave

 

[66MonacoWagon]

Yup - my vacuum advance goes straight to the carb. Is it recommended that I still bypass? I'm guessing yes.

 

[ceebuddy]

Yup - my vacuum advance goes straight to the carb. Is it recommended that I still bypass? I'm guessing yes.

Yes.

 

[66MonacoWagon]

I do still have the thermal switch and there is vacuum line running to it. Should I cap and disconnect from the system as well?

 

[Davea Lux]

I do still have the thermal switch and there is vacuum line running to it. Should I cap and disconnect from the system as well?

Yes, that will get rid of any possibility of a vacuum leak.

Dave

 

[66MonacoWagon]

Many thanks to both of you.