I've developed a very strange and hard to understand problem. I left my car at home for a week and went out of town, upon returning to my miata in my driveway this morning I checked to see if it'd start. Fired right up, no problem. Left in my MS6 and returned 3 hours later to take the miata up and have a new o2 bung welded on. Turned key on, nothing. No connection with PC and no fuel pump, no ignition.

Took the unit out of the car and inside to my bench, after fiddling for a while I ended up leaving it powered on. After sitting with power for about five minutes hooked up to the Stimulator, it just comes on like nothing was wrong without me even touching it! In the car once I get megasquirt to power on I can drive around all day literally turning the car off and on multiple times.. Normally when I leave it sit for ~ 10 hours it'll crap out and won't power on the next time I go to start it..

There is voltage inside the unit. 5 volts on input and output pins of the processor, 12 volts for all my pullups.. Can't see any bridges or flux left on the board, and I really don't know where to start. I've reflashed the ROM and that made no difference. This could potentially be a huge problem and strand me somewhere far away from home and I really don't know where to start looking from here.

 

No crappy looking joints?

 

None that I can really see. One of the very last things I did was touched up every solder joint on the PC board before final cleaning and assembly. This sucks.

 

Intermittent electrical problems are the worst. FWIW I feel your pain dude