if that was the case tho, it would stall even if you had the clutch in the whole time would it not?

 

[The following is plausible (to me, as a combustion engineer) speculation, but I don't know for sure that this is reall what is happening in the S2000.]

It's probably a vapor lock type thing. When the engine is running, the flow of fuel through the injectors cools them. When the engine stops, it's still hot but now the fuel injectors are no longer being cooled. So the heat up. (This is known as "soakback".)

Now when you try and pump fuel through them, the fuel vaporizes because the fuel injectors are hot. This leads to the so-called "vapor lock", which used to be more common with carbs.

After a short time, the injectors have cooled enough that this stops happening.

I'm using the phrase "vapor lock" very losely, because it originally referred to the heat vaporizing the fuel in the fuel pump. Since our fuel pumps are in the tank rather than the engine, it's not really the same thing.

 

As an engineer that does engine development for a living (one of my babies), I don't buy the vapor lock explanation. I've routinely shut down engines from rated power, full load and never had a vapor lock issue.

What seems more likely to me is one of two scenarios when in a spin and both feet are not in, resulting in reverse engine rotation:

1. Reverse rotation pumps exhaust into the intake manifold, which is incombustible. When you go to restart, the ECU provides fueling as normal, but since there is insufficient oxygen to mix with for combustion on the first few cycles, the engine gets flooded - probably getting the spark plugs wet and preventing spark.

2. Reverse rotation creates numerous encoder errors (that's what we call them) because the ECU is not programmed to recognize crankshaft rotation direction and thus the timing pattern detected is not expected. It may then take extended cranking for the ECU to clear the error and resynch.

Just my thoughts,
Steve

 

Either one also sounds plausible to me. That assumes there is reverse rotation, though. I guess one test would be, if you lock down the wheels but don't use the clutch, then do you still have trouble restarting? If not, then it probably does have something to do with reverse rotation. But if you do, then reverse rotation is not a likely cause.