So there I was, happily tuning along, in pursuit of the ideal PID settings for my IAC in order to get a good smooth idle and making actual progress, when after a rather minor amendment when I loaded the tune and restarted, the engine had lost it's mind.

All sense of reason completely thrown out the window, it began behaving like it had buckets for injectors and very quickly would not start at all.

Why would it do this to me? Anybody have the remotest clue what single failure could cause it? 'Cause I'm all ears.

I blamed the ignition switch and went on a 2 month long campaign which eventually got me right back to the same point of failure. Naturally I first tried earlier and earlier backups all to no avail. I've forgotten which all of the parameters I checked when it first happened, and so I'm starting back over with injector size, but I don't think that's it since I tried 3 different controllers with 2 different OS's and half a dozen or more different tunes, all with the same result.

It has to be a failure in the vehicle wiring or sensors, right? But why rich?

Your suggestions most gratefully received,

Jim

'411 P-01