MX-3.com

My car completely shuts off if I drive at over 3500rpm for more than a few minutes, and seems to shut down sooner with higher rpm. If I shut the ignition off, and coast for a few seconds, I can clutch start it, but it won't come back on if I don't turn off/ on the ignition. I am going to datalog with MegaSquirt when I figure out how, and run it until it does it again. The rpm dial shuts down, but nothing else. The car will also start right back up, with the starter, if I am on an incline, and can't bump start it.
I wonder if MegaSquirt has an auto shut down, or something.

You might be getting an overheating issue with the ms depending where you have it mounted. If its near the stock ecu location, it's possible running sustained at higher rpm will cause the area to get pretty warm because of the exhaust especially if you remove any of the insulation in between it and the firewall. That, combined with possible bad soldering could cause a thermo shut down similar to a pc. If you have enough slack in the wiring, move it to a more open area to see if that makes a difference and check the ms for any heat damage. Worst case take a friend along while hooked to a laptop to monitor the ms and replicate the conditions.

Take a datalog and try to see whats up.

Just turn on Tunerstudio; data logging, start loggin

Thanks, fellas. The MS unit is mounted to the underside of the blower housing, under the glove box. It has been there for a couple of years. I'll datalog, and see what can be made of it.

Being jam packed with sensitive electrical components, I'd try harder to keep it away from devices that create strong magnetic fields like blower motors.