I have a 5.2L 1989 RamCharger, with an SMEC. I can't seem to get MPTune to download the tune from the stock SMEC. It will connect and I can pull sensor data, but I can't get past the "connected, received xx bytes" part of reading the chip. It fails and gives an error message that basically says "can't read the boot program, turn the key off and try again." I'm using a 9v battery with 12V on pin #11, and a BoostButton.com SCI cable.

What am I doing wrong?

The goal here is to retune the engine management for the cam the previous owner installed in the truck, without going megasquirt. Hopefully I can contribute some more useful basemaps to the v8 folks. I used to tune Hondas back in the day and many of the terms are similar so it's easy to understand.