There are a half dozen things in the set-up that need to be pretty close. One overlooked item is the temp probe. If it's in too far you will likely not get past the propane start becuse of a over temp sitation. You may want to reduce the minimum battery voltage for the ECU a bit also. I have mine set at 7.0 V. With the newer batteries a couple of starts can deplete the voltage a lot and if your are using the factory settings that will not start sometimes.

JB