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rsrmike rsrmike is offline
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Join Date: Jan 2008
Location: Birmingham, AL
Posts: 538
No, the Cold start valve does not let fuel through it at all times unless it is faulty.

If the thermotime switch is unplugged the coldstart valve should not work at all, unless...

The red/black? (non-yellow) wire to the thermo-time switch is touching a ground on the engine somewhere or shorted to ground in the harness.

The way it works seems complicated at first but it's not too bad really.

Obviously the coldstart valve needs positive and neg. battery voltage to operate and these come from the starter and the thermotime switch.

Rarlyl8 is right about there being a connection between the two for the + side. This + power is supplied by the starter solenoid on a separate terminal than the one that triggers the starter.

Anytime the key is in the start position, this small yellow wire will receive + battery voltage from the starter. This power is then shared by the coldstart valve and the thermo-time switch.

The thermo-time switch only grounds the coldstart valve to trigger it under ideal conditions. There is a small heater circuit built into the thermo-time switch that heats up anytime the starter is turned. After just a few seconds this heater warms up and disconnects the ground from the coldstart valve

This is there to serve as a limiter so the coldstart valve won't flood the engine given the chance it is turned over and over repeatedly without cranking. hence the "time"

This little heater is also affected by the ambient temp of the engine as to not trigger when the engine is warm. hence "thermo"

I'll try to make this make more sense later, it's late I apologize...

Last edited by rsrmike; 02-25-2008 at 09:19 PM..
Old 02-25-2008, 09:16 PM
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