warren, is this right? I think I get the thermo-time switch now. My explanation

[lendaddy]

Ok, I am going to break down what I believe is the operating sequence of the thermo-time switch.

Of course this is based on a stone cold engine.

1. Pman turns key to engage starter, TTS is closed so the CSV injects a little extra love(fuel)

2. At the same time 12v is supplied to the TTS(during cranking only) and it reaches it's breaking point almost immediately and breaks the ground connection to the CSV.

3. Car starts due to the extra fuel in the manifold and Pman releases key to the run position

4. This action(releasing key to run) cuts power to the TTS and it's internal heating element cools quickly reestablishing ground for the CSV as the engine is still very cold.

5. I do get a little lost here as I've heard that the TTS will only stay closed for a certain amount of time no matter what but I would say the TTS would continue to give the CSV it's ground until the TTS reaches 45*C from engine heat.

So, do I have it? This would mean mine is fine right? Well as long as it cools quickly after I remove power and reestablishes ground, I will check that.

[Early_S_Man]

Yep, that's the sequence! Also ... it is why I call the CSV a mislabeled device ... it SHOULD be the: Engine NOT_Hot Enrichment Start System!

[lendaddy]

I am so proud of myself. Seriously though is there an ultimate time cutoff for the CSV? If there is it defies me as how the system incorporates it as the TTS only gets power when cranking. Man your knowledge base is awe inspiring! You saved me alot of headaches. For what it is worth I printed out every thread regarding the TTS and read them over beers and engine bay last night needless to say you made many an appearance. Thanks again.

[Early_S_Man]

While I have never seen a time limit published from Bosch, or Porsche, or VW, for that matter ... if it hasn't opened in two minutes, then I would think that the contacts are 'sticking' or welded shut ... ala, the similar switch that caused the LOx tank to explode in the Apollo 13 mission!

[john walker's workshop]

it will ground again after a few seconds, for a few starting attempts, and will be warmed by the engine, after it runs a bit, so it will not be grounded when hot.

Is the time constant for the switch short enough to affect the starting mixture in the following scenario?
My car, like quite a few apparently, is (mis)wired in such a way that the fuel pump comes on with the ignition key, not with the starter.
My habit has been to listen for the change in tone from the pump that indicates it's up to pressure, then kicking the starter.
If the time constant on the TTS were very short, could I be missing the enrichment from the CSV by waiting for the pump to pressurize?

OH, I see. TTS only powered when cranking, so I'm not causing it a problem by waiting.
Never mind.