Pro tip: a $20 infrared thermometer saved my bacon on a stubborn injector job

I was working on a 6.7 Powerstroke with a rough idle, and I was convinced cylinder 3 was the culprit based on the scan tool. My buddy told me to just swap the suspect injector with another one and see if the code moved, which would have taken me half a day. Instead, I grabbed my cheap infrared thermometer and shot each exhaust manifold runner after a cold start. Cylinder 5 was a full 150 degrees cooler than the others after just two minutes. Swapped THAT injector, problem solved in under an hour. The scan data pointed one way, but the simple temp gun told the real story. Anyone else have a go-to 'low tech' trick that beats the fancy stuff sometimes?

3 comments

3 Comments

joel_hall171mo ago

But isn't that scan tool data still the first clue you need?

josepha321mo ago

Guess the computer wanted a day off too, huh?

milesbailey1mo ago

Yeah the "day off" thing is real. My buddy's truck kept throwing random codes and the scanner showed nothing. Turned out a mouse chewed through a wiring harness in his garage. The computer basically gave up and shut down because the signals were all wrong. He spent a week checking sensors before he found the nest.