Rough running when cold (6.9)

[browndog]

My 1977 6.9 has started running very rough when it is cold. The car starts fine, run's great when warm, but feels like it a diesel when cold. If I rev the engine it smooth's out. Cold start vale? Is there a way to test it?

Thanks!

 

[Bandolero]

I doubt if it is the cold start valve.
These problems can range from the Aux Air Valve to the Warm Up Regulator.
Check there is power going to the WUR with the ignition on.

I live in a temperate climate and don't need the cold start valve as the wires to it have been broken for the last 3 years. I finally fixed the wiring the other week and it makes no difference to the starting from cold.

To shut the extra fuel off that is needed for cold start/run, the WUR uses a bi-metal strip (from the 12 volts power) that slowly closes off an internal valve and also the heat off the motor that warms up the base of the WUR that also shuts off the same internal valve.