Volkswagen Air-Cooled 1970-1981 Repair Guide

Cold Start Valve

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The cold start valve is located on the air intake distributor and is held by two screws. The cold start valve operates only when the engine and the outside air are cold. It injects fuel into the air intake distributor for several seconds when the starter is engaged and then shuts off. If the valve is not working, it will be very difficult to start the engine; if the valve is leaking, it could cause flooding while starting, especially if the engine is hot. The cold start valve is controlled by a thermo-time switch or, on some models, a thermostat. Power for the valve is fed from terminal 50 of the starter.

CHECKING VALVE LEAKAGE



Remove the cold start valve from the engine after detaching the electrical connector. Tape the connector's end to prevent sparks. Leave the fuel line attached. Disconnect the high tension ignition coil wire to prevent the engine from starting and have an assistant engage the starter while you hold the valve nozzle up in a rag.

See precautions in Tune-up for electronic ignitions.

If fuel forms on the nozzle and begins to drip off, the valve is leaking and should be replaced, or fuel pressure is too high.


CAUTION
Fuel might be expelled from the valve, so do not smoke and do not allow any electrical connections (coil wire, etc.) to cause sparks.

CHECKING VALVE OPERATION



  1. Remove the cold start valve from the engine leaving the fuel line attached.
  2.  
  3. Remove the high tension wire from the middle of the ignition coil and put tape over the coil terminal to prevent sparks.
  4.  

See precautions in Tune-up for electronic ignition.

  1. If you haven't done so already, detach the electrical connector from the cold start valve.
  2.  
  3. Have a container ready to catch gasoline and using a jumper wire, connect one of the terminals on the cold start valve to ground. Connect the other terminal of the cold start valve to terminal 15 of the ignition coil using another jumper cable.
  4.  
  5. Point the nozzle of the cold start valve into the container and have an assistant turn the ignition to the ON position.
  6.  


CAUTION
Be careful not to allow the jumper wires to touch each other and do not smoke, as fuel will be expelled from the valve if it is working.

  1. A spray of fuel should come from the valve while the ignition is on. If not, the cold start valve is not working correctly.
  2.  
  3. Reconnect the cold start valve electrical connection. Turn the ignition to ON. If the cold start valve injects fuel with the ignition in the ON (not START ) position, there is a good possibility that the cold start valve wire that belongs on terminal 50 of the starter has been mistakingly connected to terminal 30.
  4.  

This test has been for the cold start valve itself, not the other components of the cold start system (thermo-time valve, relay, etc.). If your vehicle still starts hard on cold mornings, the problem could be with the thermo-time switch (thermo-switch on some models). It is best to let your dealer troubleshoot these components.

 
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