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Discussion Starter · #1 ·
'77 280 no longer "idles up" from cold start, so I know it's
one of two things. But as the Thermotime swith acts on
the Cold Start Valve, is there a way to test them independantly? As one costs twice as much as the other, I'd like to replace the right one FIRST!
Does the Thermotine provide a measurable signal
(using a ohm-meter)?
 

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RE: Thermo or CSV?

I am assuming that you mean the the idle speed is too low when it is cold. This is caused by the aux. air valve which is locate on the top of the intake manifold. They have a tendency to go south. You can buy a new one but they are rather expensive or you can try your luck with a juckyard one. However, they almost never work. I would just forget about it if I were you. Or if it really buggs you, buy a new one. BTW, the cold start valve is a large fuel injector that squirts fuel into the intake manifold only while you are cranking it over. As soon at the engine fires, it shuts off. Also, the thermotime switch controls the csv so that the csv only works below a certain temperature (really cold). Therefore, it would have no bearing on the engine's idle speed. Anyway, good luck!!!

Ian
 

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Discussion Starter · #3 ·
RE: What if idles good cold/low when hot???

Mine idles well when cold, but as it gets warm enough for the air reg to disengage, the idle drops down farther and farther until the car stalls hald the time when you let off the accelerator pedal.
 
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