AAR Question, Can it be removed? Options

[flat4tom]

Hello everyone,

In going over my car's vacuum lines - waiting for my fuel injectors to be returned from servicing - I decided to replace the hose from the AAR valve to the cold start valve. Then I started to think - a dangerous thing - why do I need the AAR if the cold start valve is disconnected? It currently has no fuel supply so it's not working.

Currently my AAR is stuck open. Should I try to free it and reinstall it, or can I just plug the hose to the cold start valve and not bother putting it back?

Before I pulled the injectors for service, when my car was running (I am getting this car running again from a 3 year sleep) it had a way high idle ~ 1400rpms - so there's undoubtedly vacuum leak(s) somewhere.

Any input is welcome.
Thanks!
Tom
'73 2.0

[McMark]

The AAR keeps your idle up while the car is warming up. It's worth taking the time to fix it. It has nothing to do with the cold start valve. And further, the cold start valve only fires under the following conditions:

The 'engine temperature'* is below 95 degrees and ONLY while the motor is cranking and ONLY for 5-12 seconds (depending on the number of degrees below 95).

*-Engine temperature is measured by the thermotime switch, which is mounted under the main plenum. It's not oil temp and it's not CHT.

[pbanders]

The AAR keeps your idle up while the car is warming up. It's worth taking the time to fix it. It has nothing to do with the cold start valve. And further, the cold start valve only fires under the following conditions:

The 'engine temperature'* is below 95 degrees and ONLY while the motor is cranking and ONLY for 5-12 seconds (depending on the number of degrees below 95).

*-Engine temperature is measured by the thermotime switch, which is mounted under the main plenum. It's not oil temp and it's not CHT.

Actually, it's a lot lower than 95 deg. F before the CSV is opened by the thermoswitch (or thermo-time switch). Trigger temps vary by part number, but all of them are below 40 deg. F. This is from my web page (data from Jeff Bowlsby):

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

... and as you pointed out, the CSV is open ONLY during cranking. If you have a later car with the thermo-time switch, after the total time cranking exceeds about 20 seconds, the heater in the switch will have opened the bimetallic contacts and it won't operate the CSV any more to avoid flooding.

FWIW, I don't think the CSV on my car has EVER been opened by the thermoswitch. That's what I get for living in CA and now in AZ (IMG:style_emoticons/default/smile.gif)