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-   -   Thermo time switch (http://www.peachparts.com/shopforum/showthread.php?t=375988)

Mpwood 03-01-2016 05:06 PM

Thermo time switch
 
Is there a procedure for testing the thermo time switch in D jet applications. I'm not getting power to the cold start valve. I've changed out the CSV relay and tested the ground to the TTS. Resistance across the poles of the TTS is 33.3 ohms and 33.3 from the G pole to ground and 2-3 ohms from the W pole (or vice-a-versa). When I supply direct power to the CSV, it functions properly.

meltedpanda 03-02-2016 11:04 AM

test these too

Temperature Sensor I

Temperature Sensor I is an ambient air temperature sensor.As the ambient air temperature decreases,the density of the air increases.As a result,the ECU must inject more fuel on a cold day than on a warm day.

Temperature Sensor I is a temperature sensitive resistor known as negative temperature coefficient thermistor (NTC). This sensor has a resistance of between 400 and 500 ohms at 50 degrees F. At 100 degrees F.,the resistance is between 150 to 200 ohms.

Temperature Sensor I actually has little effect on the operation on most D Jetronic equipped vehicles.This is because most of these cars have tens of thousands of miles on the engine and are running very rich due to this wear.The troubleshooting consequence of this is that disconnecting the air temperature sensor during the diagnostic procedure may have little effect on the way the engine runs,and in some cases it may actually improve the way it runs.

Temperature Sensor II

Temperature Sensor II is the coolant temperature sensor on water cooled engines.Like temperature sensor I, it is a NTC thermistor.The temperature of the engine is important because the intake manifold design of fuel injected engine does not permit the use of an air restictive choke.Additionally,restricting the air to enrich the engine during warm up would cause inaccurate readings from the manifold pressure sensor.The warm up choke function is therefore performed by Temperature Sensor II.

When the coolant temperature is about 50 degrees F.,the resistance of Temperature Sensor II is between 3000 and 4500 ohms.As the temperature increases to more that 120 degrees F.,the resistance drops to less than 1000 ohms.Thus the sensors work is done once the engine is warmed up.Also it must be continuously remind the ECU that the engine has warmed up.If damaged,Temperature Sensor II will not continue to partially function( such as the resistance values shifting). It will completely fail,creating an open short or ground.

An open circuit in Temperature Sensor II or the wiring leading to it will cause the engine to run extremely rich once warmed up.Symptoms would be dark smoke from the tailpipe (most noticeable at idle),rough idle and poor power.Keep in mind that these same symptoms could also be caused by engine compression problems and ignition.

Should the sensor become shorted or the wiring harness grounded,the effects may not be noticeable at all when the engine is warmed up.The symptoms would be more like a carburetor with the choke stuck open-rough or erratic idle,stalling or hesitation when the engine is cold and progressively running better as the engine warms up.

On the KEjet ( looking for the D jet specifics) the thermo time switch when cold should show 5 volts or so at one of the wires, when warm the voltage on both wires is 0

meltedpanda 03-02-2016 11:31 AM

this may help as well'
from the Pagoda folks
Pagoda SL Group Technical Manual :: Engine / ThermoTimeSwitch


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