Spent 6 hours chasing a phantom misfire on a 2014 F-150 with the 3.5 EcoBoost

It turned out to be a tiny crack in the plastic charge air cooler pipe that only leaked under full boost, and my smoke machine test didn't show it. Has anyone else found a better way to find these hidden boost leaks without just throwing parts at it?

3 comments

3 Comments

adams.faith1mo ago

I've had good luck with a soapy water spray bottle on a hot engine bay.

jana_hernandez1mo ago

Wait, you ran a smoke test and it still didn't show up? That's wild, those things are supposed to find everything. Makes me wonder if my own smoke machine would miss something like that too. A tiny crack under full boost pressure is such a nightmare to track down. I guess sometimes you just have to get creative when the usual tools fail.

felix1551mo ago

Actually @jana_hernandez, smoke machines can miss really small leaks, especially if the crack only opens up under real engine heat and pressure. The soapy water trick Faith mentioned is solid, but for a boost leak you might need to pressurize the intake system with an air compressor while the engine is cold and then spray it down. That combo often finds what smoke alone misses.