Thermotime switch off 280zx L28

[jjohnson]

wondering If anyone has a working thermotime switch in perth

Sean.

[gema]

At the risk of sounding ignorant...what on earth is a thermotime?

[jjohnson]

Pages 16-18 of the 280z Fuel Injection Book credit Cardinal Zen for the book, Kammy for the post

Quote:

'Thermo-Time Switch

The thermo-time switch consists of a contact to ground for the cold start valve and a bimetallic strip surrounded by a heater winding. When the engine is cold and the key is turned to "start," the bimetallic strip contacts the ground contact and allows the cold start injector to inject fuel. When the key is turned to "on," that powers the heating element inside the thermo-time switch. As the heater warms the bimetallic strip, it eventually bends away and stops grounding the cold start valve.

This all happens in 10 seconds or less. This is to keep the cold start valve from injecting too much fuel and flooding the engine. So if the engine doesn't start within the 10 seconds, the thermo-time switch will shut off the cold start valve to keep the engine from flooding for future starting attempts. When the engine is already hot, the contact in the thermo-time switch is open, preventing the cold start valve from operating. A stuck closed thermo-time switch could allow the cold start valve to operate too long during starting, causing engine flooding (but regardless, the cold start valve will still only operate when the starter is operating). If the thermo-time switch sticks open, it could keep the cold start valve from operating and cause hard cold starting.

The thermo-time switch can be tested electrically. The temperature at which the switch activates is stamped on the switch housing. You can install a test lamp in series with the wire to the thermo-time switch, disable the ignition, and crank the starter. The lamp should light but then go out in a few seconds of cranking.

The switch can also be tested for resistance between the two terminals. It should vary with temperature, being close to zero when the switch is below the temperature marked on the housing and being infinite when the switch is warm.'

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Hope that helps...Basically I need a thermotime switch as when cold my car starts rough and hard, but once warmed it idles fine, as if nothing is wrong

Thanks.

Sean

[sblake01]

Essentially, the Thermotime Switch/Cold Start Valve/Air Regulator combination on a F.I. car functions similar to an automatic choke on a carbureated car