A few weeks ago we got in the truck, let the glow plugs warm up, then as I reached for the key to start it we heard what sounded like a shotgun going off under the hood, and then smoke drifting out. Found a hole blown out of the top of the air cleaner box.

After a bit of thought it became clear what had happened. The propane injector was left on, and propane had dropped into a cylinder and been ignited by the glow plugs. So I learned the propane should be off until the truck is running. I turned it off at the tank and decided I’d mess with it later. A bit of plastic weld and we were back on the road.

Last week I decided it was time to give the propane injection system a good test. I was careful to turn the valve off before turning off the truck. The fourth time I started it after turning on propane at the tank, it blew again. This time it was beyond plastic weld (see the image above).

Apparently the solenoid is leaking propane even when the switch is off. Sigh.

So the first decision was to get rid of the propane. We’ve getting decent mileage and plenty of power without it so it’s not necessary. Besides, full it’s over 300 pounds! The tank is set up with a wet leg so I can drain the propane into the smaller tanks we have for the RV.

Which still left us with couple of big holes in our air cleaner cover. I could get a replacement at a local pull-n-save, but I’d already toyed with doing a K&N replacement to get more air into the engine. The one I chose is supposed to give a 9% increase in horsepower, which should match or exceeded what the propane was supposed to do for me.

Isn’t that a thing of beauty?!