My wife has a 164 that had a no start problem when the car was shut down and then restarted during hot weather. Thru this board forum I found out that the cold start valve was injecting a shot of fuel for starting that wasnt necessary......so I rigged up a toggle switch so that the cold start could be manually operated only when recquired. Worked fine. But now this year as the weather becomes warm,the no start condition has returned! Wife took the car into the shop ($200) and they could find nothing wrong with it (igniton parts were still new from Fall tune up). Anyone have any ideas about this problem? Any help appreciated.

Might be dripping injectors. One way to tell is to pull them all out, still
connected to the rail, put several layers of newspaper under them, disconnect
the coil wire and crank the engine. They should all spray. After cranking,
watch them and see if they drip. You could also do it by connecting a pressure
gauge in place of the cold start injector and watching the pressure after
cranking. If it goes down fairly rapidly after cranking that indicates a
leak somewhere, possibly from injectors or possibly from the fuel pressure
regulator.

The dripping injectors will give the same over-rich condition at startup
as the cold start injector, which you should not have had to disconnect.
You might also want to check your temp sensors, (and their associated wiring) especially the one screwed into the head, since an indication of too cold will
make the mixture too rich.
--
George Downs, Bartlesville, Oklahoma, Central US

First try running a heavy-duty fuel injector cleaner product through the system. Perhaps deposits on the injectors are fouling them.

Mike!