TIL a cracked injector line can make a 6.0 Powerstroke run like it's got a miss

I spent a whole Saturday chasing a miss on a 2006 F-350. Checked the ICP sensor, tested the FICM voltage, even pulled valve covers to look at rockers. Turned out it was a hairline crack on the #5 injector high pressure line that only showed up when the engine got hot and expanded. I only found it because I let the truck idle in the dark and saw a tiny flash of fuel mist catching the headlights. Has anyone else found phantom issues by just letting the engine sit at night?

2 comments

2 Comments

jade22120d ago

Man, that trick with the dark is genius. I spent three hours once chasing a vacuum leak on an old Cummins, only to find out it was just a loose hose clamp I'd missed because I was too busy looking at the fancy stuff. My wife thinks I'm crazy when I'm out there at 2 AM staring at a running engine, but hey, it works. That tiny flash of fuel mist is the only way I've ever found a cracked line too, feels like you're a detective or something. Glad you found it, nothing worse than a Saturday wasted on a ghost miss.

west.alice19d ago

The dark trick is seriously underrated, especially on older diesels where everything is vibrating and you can't hear a thing. I've done the same thing with propane on gas engines too, but the flashlight method feels way more precise once you get the hang of it. There's something satisfying about finding a leak that way, like you're using some ancient mechanic wisdom passed down from the guys who worked on these trucks when they were new. Those ghost misses are the worst because you start questioning everything, even your own sanity, especially when it's something dumb like a clamp you swore you tightened.