308 QV High Idle Issue

Hello Guys:

Is the thermoswitch on the expansion tank just an open/close switch or does it change resistance as the car warms ? If it is a switch, should it have continutity when cold or hot ?

I lost hi-idle, since I replaced the leaking expansion tank and am wondering if I screwed up either the thermo-switch or the AAV, both of which needed to be removed when swapping the tank.

Many thanks,

Oleh

I thought the coolant temp sensor on the tank controlled open/closed loop operation of the lambda sensor on the 84/85 QV. I wasn't aware that it did anything to the AAV. Could you explain?
If I remember correctly it has continuity when cold. It has been a while since I tested mine.
I think 83s have them too and they have no lambda sensor so I would like to know more about that.

Found this in the archives.

Hi Rich,

the coolant temp sensor on the header tank sends a signal to the Ignition ECU that it's time to advance the timing. Those switches open at about 140F. Ferrari retards the timing and raises the idle for faster warm-ups and reduced "overall" emisions by heating the engine faster.

Regards, JRV

Thanks for the clarification. Must be with the AAV. Mayber I didnt reconnect it when I reinstalled the tank. Will check this weekend.

THX

Here is a great site covering the Mechanical Fuel injection System.

http://www.auto-solve.com/mech_inj.htm