Abe,

This theory sounds somewhat improbable. The idea that carbon deposits might be washed onto the exhaust valves in such a way as to cause them to not seal seams far fetched, at best. Realize that, at any given instance with an engine off, only one or maybe two cylinders in our five cylinder engines will have exhaust valves open in such a way as to be able to get anything between the valves and seat. That leaves three or four cylinders unaffected by this phenomenon, which should be enough to fire the engine and clear things out pretty quickly.

A few weeks ago, I posted a reply to a similar experience that another Brickboarder was having. See:

http://brickboard.com/READER/?file=10052518&referer=AWD&fromindex=1

In that post, I referred to a well known issue that affects a different type of engine, and that extraordinary efforts were needed to start those vehicles that were flooded due to the same cause that I believe affected Dan's car. I did not state at that time that one of the de-flooding techniques for those engines was to inject a small amount of motor oil into the spark plug holes of that type of engine. This is a well known fix for those engines, and I bring it up now because it reinforces my point about what happenned to Dan's (and Gian Paolo's) engines. (If anyone's really curious, see the following URL for an explanation of the unflooding method on the engines that I refer to:

http://www.rx7.com/tech/unflood-fc.html

The pictures are messed up, and the article doesn't explain in depth WHY this happens to these engines, but the symptoms and fix are accurately described.)

I also suggested in that post for Gian Paolo that a weak battery would agravate the situation, and Ken's post in this thread reminded me that "batteries are part of the ignition system." In a broader sense, Ken's absolutely right that weak ignition systems will aggravate this flooding problem on both types of engines that I'm discussing here. A stronger spark will help burn an excessively rich mixture before flooding can occur -- thus helping to prevent the problem immediately before a cold shutdown -- and that same stronger spark will help to start an engine with low compression after the cold-shutdown syndrome has taken effect.

Dan, Abe and anyone else, please consider what I'm describing here. I'm not the type to start an arguement on a web forum, but I think that an understanding of this issue will be in the Brickboard community's best interests. Let me know what you think and we can kick it around a little more.

If we can't agree on what we can't actually see, so be it.