testing cold start valve on a 930

[gumba]

This is a spare cold start valve off another motor. Can I put 12 volts to the leads to check if it's working (off the car)?

[T77911S]

yes, i would think you could feel/hear it open and close.
check it with an ohm meter. i dont know what the resistance is

[boyt911sc]

Originally Posted by gumba

This is a spare cold start valve off another motor. Can I put 12 volts to the leads to check if it's working (off the car)?

gumba,

Simply applying 12-volts to the CSV terminals does not give a conclusive test result whether the CSV is good and operative. You need to test with power and fuel pressure. You like to see the spray pattern of the fuel when the CSV is energized. They seldom go bad. You would need a minimum 40 psi. to open the injector.

Tony

[gumba]

Thanks.
Does the csv continue to spray fuel when the motor is running to help with the cold idle. Or just inject fuel when cranking for start up.

[boyt911sc]

Originally Posted by gumba

Thanks.
Does the csv continue to spray fuel when the motor is running to help with the cold idle. Or just inject fuel when cranking for start up.

gumba,

The CSV is controlled by the TTS (thermotime switch). When the engine temp. is below 113°F, the TTS is grounded and completes the circuit for CSV to operate during start-up. When the engine temp. gets over 113°F, the TTS opens up and loses the ground contact thus making the circuit for the CSV open. To prevent fuel flooding during cold start up, the TTS has about 8 seconds before it switch to open position (controlled by an internal heater). The ignition switch supplies power to the starter, CSV, and TTS.

The CSV operates when the ignition switch is @ START position only and TTS closed (cold engine).

Tony

[puddy]

1 out of 4 times i start my car it will just crank for a good 30 seconds or more and wont start unless I manually modulate the gas pedal. The rest of the time it fires right up no problem. Could this be a symptom of a CSV going bad?

[T77911S]

its possible. but there are other parts to the circuit that are more likely to go bad.
power comes from the starter when cranking.

I have never had to test my CSV so this is only from how I would approach it. tony may have a better way. BTW tony, the TTS is VERY hard to get to in the 930, at least mine is. I would use a test light since it may be easier to get down in there.

start with the connection at the starter. make sure it is clean and good.
the start wire is yellow and the wire to the CSV is yel/bl
I would connect a test light to 12v then probe the 2 pins on the TTS. if they BOTH light it, the one that is brighter would be the hot side from the CSV. the other is ground.
connect TL to ground and have someone crank it while testing the HOT side of the TTS for power.
if it does NOT light then you are not getting power to/from the CSV.
power does not go thru the CSV so the connector does not have to be on the CSV to get power to the TTS.

[Flat6pac]

Power comes by the temperature probe in the left chain cover.
Bruce