Overheard a guy at the parts counter say something that clicked for me

I was getting injectors yesterday at the freightliner dealer in Spokane and this older mechanic told the kid behind the counter 'you can't fix what you don't measure'. He was talking about a high pressure oil leak. It hit me that I've been chasing a rough idle on a 6.7 Cummins for two weeks just swapping parts instead of actually doing a proper cylinder contribution test. Anyone else ever catch themselves just throwing parts at something cause you're too lazy to dig out the scan tool first?

2 comments

2 Comments

wesley1811mo ago

Why should I drag out a scan tool when my ears and a flashlight have solved 9 out of 10 problems the last 15 years? Half the time those contribution tests just tell you what you already knew if you just listened to the engine and checked the basics first. I've seen guys spend an hour hooking up a scanner to tell them cylinder 6 is misfiring when a simple wiggle test on the injector harness wouldve found the chafed wire in 5 minutes. Plus some of those aftermarket scan tools are junk anyway and give you false readings that send you down the wrong rabbit hole. Not saying measuring is always bad but sometimes you just gotta trust what your hands and eyes tell you.

kevin_west1mo agoMost Upvoted

Wait, you actually trust your ears over a scanner?