Check Engine light

So, I've been having an ongoing argument with my Check Engine light.

Finally figured it out the other day. Here's the scoop: I have my valves and purge timer wired to an "ignition" 12v source. This works fine while the car is running, and works fine when I switch back to diesel, let the car purge and then shut the car off. However, anytime I tried to shut the car off on veggie for a short stop, it would rev high for a few seconds, then shut down. When I restarted, it would give the Check Engine light.

After some presuming and postulating, I figured out that when I was shutting the car OFF, the valves were switching over at the same time... confusing the electronic shutoff valve. This car doesn't have a simple solenoid valve, the ESV(electronic shutoff valve) actually reverses the flow of fuel into the injection pump. Because my valves were switching back to diesel when I was shutting the car off, it wasn't giving the ESV a continuous source of suction on the fuel line.

Solution: I switched to a +12v "accessory" feed for the valves and purge timer. Works great now, and no Check Engine light.