I'm running a pretty basic 350 engine and have been happy with my 7747 tune for a few years now. Thing is, I always park my project in the winter. Last night my wife left the garage door open and it got down to about 20* F. Normally, the engine pops right off, but this time it simply wouldn't start. I cranked the hell out of it at about half throttle and it eventually sputtered alive after nearly running the battery dead.

I seem to have some sort of starting issue that goes from no problem at like 40* to ruinous at 20*. Any thoughts? "AFR during cranking" is the obvious one to play with, right? It's a little weird to me though that I'd have such an issue with a standard 350 with a factory 350 bin file. Is there something I might be missing?

Debugging this will be tough since I'm normally tucked in a warm garage. I'd have to purposely leave it out...

 

Mastiff

I would check the basic stuff - i.e. do you have a steady fuel pressure during very cold start up. I took a quick look at ASDU bin file - AFR during cranking and the difference is not that great between two temperatures (20 to 40F).

//RF