happens first start in the morning. lol. i hate intermittent problems. i hear of tar buildup but have never seen it. i guess we have clean propane.

See if it happens again sometimes when hot they would fail the one box was better than the separate boxes also if you don't here it check the two wires one is neg to lock l think one was red in color that one is neg don't ask me why they used red for neg the other is positive you should get a click when you turn key on for a second and then when cranking if you have positive at fuel lock wiring and neg l would check fuel lock this system was not very good it would gum up and lock would stick closed also same problem with converter it would gum up and have problem starting when cold

Looks like aisin. single box under air cleaner. i dont recall hearing the fuel solenoid click on last time. today it did and started. This happened a few weeks ago too.

Is the propane system a assin system if so look by the air cleaner frame the box if it used one is appox three by three and is black in color. Let me know.

I will need to go back out there to check. I didnt see anything near the coil or distributor.

sounds like what i need to get moving in the right direction. i will check it out when i get back to it.

What l am thinking is this truck using a Assin propane system if so the early models had to separate small boxes one mounted by the coil and the other one mounted by the air cleaner the one mounted by the coil controlled the spark it used positive out of the box to controll the spark it delayed the spark for approx three seconds the other box controlled the propane it used neg from the coil to open the fuel lock. On the later models they incorporated the spark and fuel into one larger box that was mounted on the frame of the air cleaner it had l believe a plug with six wires attached to it it is possible that the box is bad but that is where the wire is going to it. When cranking it see the neg signal and starts the flow of gas if not this propane converter is a positive displacement meaning it gets fuel as soon as the key is on.with out the box it would get fuel with the key and there is a chance of a fire without it it will not open the lock untill it sees the engine cranking.hope l was of help.