cold start system does not work . i have changed c/s inj. time switch, coolant temp. sensor (2 wire next to c/s inj.time switch ) connector on c/s inj.time switch was broken, so got new connector cap, but wires may have been installed backwards . when key is turned to start, 4volts in black / white striped wire. when cold (at 35 degrees) when hot, 12 volts at b/w wire when b/w wire @ c/s injector is grounded to battery. c/s injector works when wire with 12 volts is connected , & ignition switch is activated .
There are two wires going into the cold start injector. The black and white wire should get 12 volts only when the key is turned to the START position. As soon as the key drops back to RUN, it shouldn’t have any voltage. The clutch pedal also has to be depressed if it’s a manual transmission.
The resistance on the time switch should be 30-50 ohms if it’s below 50 degrees and 70-90 ohms if it’s above 77 degrees. Basically it should ground the circuit for the cold start injector if it’s cold.
With the key turned on, you’re just measuring the voltage through the coils of the time switch. The injector should never have 12 volts unless the key is in the start position and the clutch is depressed or the cancel switch has been tripped.
The cold start injector will help with starting, especially when it’s 35 degrees or less. It won’t keep a truck from starting. It will only make it start easier, and only when it’s cold.
TESTING:
The easiest way to check it electrically is to put a test light on the black and white wire on the cold start injector and see if it lights when the starter is engaged.
Then hook the test light to the green wire and it shouldn’t light when it’s below 50 and the starter is engaged. That will check the electrical side. I’ve never seen a cold start switch fail, but then I only worked on about 12,000 Toyotas before I quit counting. If they fail it’s because the injector gets plugged up. This is more common in Florida and California because it could go for 8 or 10 months and not get below 50. This gives the injector a chance to gum up.
Another test is to unbolt the fuel line from the injector. Be careful because it’s going to spray gas. Go down to the hardware store and get a nut that fits the hollow bolt that goes through the banjo fitting. Skip that last sentence. I was delusional for a minute. It happens with us seniors. There are two parts to the circuit. Power side and ground side. Power comes from the ignition switch, through the starter relay to the injector. The starter relay is triggered by the clutch switch or the clutch cancel switch. But if the relay isn’t being triggered, the starter won’t work. So if there is a break in the power side, it has to be between the starter relay and the cold start injector. The ground side of the circuit is the cold start timer switch. The cold start switch has a switch like a thermostat. But there is also a timer in it so if you crank on the starter too long, it turns off to keep from flooding the engine.
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