A customer called me out for how I was checking injector balance rates

I was working on a 6.7 Powerstroke with a rough idle, running my usual test. I had the scan tool hooked up and was just looking at the numbers, thinking one was a bit off. The guy who owned the truck, an older farmer, was watching and said, 'You're just looking at it cold, right? You gotta get it up to temp and put a load on it. The computer lies when it's cold.' I argued for a second, but he was right. I let it warm up fully, then put it in gear with the parking brake set to load the engine. The balance rates shifted completely, and the bad injector popped out clear as day. I would have chased my tail for an hour. Now I always do a hot, loaded test first. Anyone else have a simple step they used to skip that actually matters a lot?

2 comments

2 Comments

sam_hart14d ago

Wait you were just checking them cold? lmao that's wild. Yeah that old farmer saved you a ton of time.

juliadavis13d ago

Yeah checking them cold is a classic newbie move. I read somewhere that letting them warm up first gives you a real reading, otherwise you're just wasting your time.